layout-radial turtle-set link-set root-agent
Arranges the turtles in turtle-set connected by links in
link-set, in a radial tree layout, centered around the
root-agent which is moved to the center of the world view.
Only links in the link-set will be used to determine the
layout. If links connect turtles that are not in turtle-set
those turtles will remain stationary.
Even if the network does contain cycles, and is not a true tree
structure, this layout will still work, although the results will
not always be pretty.
to make-a-tree
set-default-shape turtles "circle"
crt 6
ask turtle 0 [
create-link-with turtle 1
create-link-with turtle 2
create-link-with turtle 3
]
ask turtle 1 [
create-link-with turtle 4
create-link-with turtle 5
]
; do a radial tree layout, centered on turtle 0
layout-radial turtles links (turtle 0)
end
layout-spring turtle-set link-set
spring-constant spring-length repulsion-constant
Arranges the turtles in turtle-set, as if the links in
link-set are springs and the turtles are repelling each
other. Turtles that are connected by links in link-set but
not included in turtle-set are treated as anchors and are
not moved.
spring-constant is a measure of the "tautness" of
the spring. It is the "resistance" to change in their
length. spring-constant is the force the spring would exert if
it's length were changed by 1 unit.
spring-length is the "zero-force" length or the natural
length of the springs. This is the length which all springs try to
achieve either by pushing out their nodes or pulling them in.
repulsion-constant is a measure of repulsion between the nodes. It
is the force that 2 nodes at a distance of 1 unit will exert on
each other.
The repulsion effect tries to get the nodes as far as possible from
each other, in order to avoid crowding and the spring effect tries
to keep them at "about" a certain distance from the nodes
they are connected to. The result is the laying out of the whole
network in a way which highlights relationships among the nodes and
at the same time is crowded less and is visually pleasing.
The layout algorithm is based on the Fruchterman-Reingold layout
algorithm. More information about this algorithm can be obtained
here.
to make-a-triangle
set-default-shape turtles "circle"
crt 3
ask turtle 0
[
create-links-with other turtles
]
ask turtle 1
[
create-link-with turtle 2
]
repeat 30 [ layout-spring turtles links 0.2 5 1 ] ;; lays the nodes in a triangle
end
layout-tutte turtle-set link-set radius
The turtles that are connected by links in link-set but not
included in turtle-set are placed in a circle layout with
the given radius. There should be at least 3 agents in this
agentset.
The turtles in turtle-set are then laid out in the following
manner: Each turtle is placed at centroid (or barycenter) of the
polygon formed by its linked neighbors. (The centroid is like a
2-dimensional average of the coordinates of the neighbors.)
(The purpose of the circle of "anchor agents" is to
prevent all the turtles from collapsing down to one point.)
After a few iterations of this, the layout will stabilize.
This layout is named after the mathematician William Thomas Tutte,
who proposed it as a method for graph layout.
to make-a-tree
set-default-shape turtles "circle"
crt 6
ask turtle 0 [
create-link-with turtle 1
create-link-with turtle 2
create-link-with turtle 3
]
ask turtle 1 [
create-link-with turtle 4
create-link-with turtle 5
]
; place all the turtles with just one
; neighbor on the perimeter of a circle
; and then place the remaining turtles inside
; this circle, spread between their neighbors.
repeat 10 [ layout-tutte (turtles with [link-neighbors = 1]) links 12 ]
end
links-own [var1 ...]
<link-breeds>-own [var1 ...]
The links-own keyword, like the globals, breed,
<breeds>-own, turtles-own, and patches-own keywords,
can only be used at the beginning of a program, before any function
definitions. It defines the variables belonging to each link.
If you specify a breed instead of "links", only links of
that breed have the listed variables. (More than one link breed may
list the same variable.)
undirected-link-breed [sidewalks sidewalk]
directed-link-breed [streets street]
links-own [traffic] ;; applies to all breeds
sidewalks-own [pedestrians]
streets-own [cars bikes]
list value1 value2
(list value1 ...)
Reports a list containing the given items. The items can be of
any type, produced by any kind of reporter.
show list (random 10) (random 10)
=> [4 9] ;; or similar list
show (list 5)
=> [5]
show (list (random 10) 1 2 3 (random 10))
=> [4 1 2 3 9] ;; or similar list
ln number
Reports the natural logarithm of number, that is, the
logarithm to the base e (2.71828...).
See also e, log.
log number base
Reports the logarithm of number in base base.
show log 64 2
=> 6
See also ln.
loop [ commands ]
Repeats the commands forever, or until the enclosing procedure
exits through use of the stop or
report commands.
to move-to-world-edge ;; turtle procedure
loop [
if not can-move? 1 [ stop ]
fd 1
]
end
In this example, stop exits not just the loop,
but the entire procedure.
Note: in many circumstances, it is more appropriate to use
a forever button to repeat something indefinitely. See
Buttons in the
Programming Guide.
lput value list
Adds value to the end of a list and reports the new list.
;; suppose mylist is [2 7 10 "Bob"]
set mylist lput 42 mylist
;; mylist now is [2 7 10 "Bob" 42]
map reporter list
(map reporter list1 ...)
With a single list, the given reporter is run for each item in
the list, and a list of the results is collected and reported.
reporter may be an anonymous reporter or the name of a reporter.
show map round [1.1 2.2 2.7]
=> [1 2 3]
show map [ i -> i * i ] [1 2 3]
=> [1 4 9]
With multiple lists, the given reporter is run for each group of
items from each list. So, it is run once for the first items,
once for the second items, and so on. All the lists must be the
same length.
Some examples make this clearer:
show (map + [1 2 3] [2 4 6])
=> [3 6 9]
show (map [ [a b c] -> a + b = c ] [1 2 3] [2 4 6] [3 5 9])
=> [true false true]
See also foreach, -> (anonymous procedure).
max list
Reports the maximum number value in the list. It ignores other
types of items.
show max [xcor] of turtles
;; prints the x coordinate of the turtle which is
;; farthest right in the world
show max list a b
;; prints the larger of the two variables a and b
show max (list a b c)
;; prints the largest of the three variables a, b, and c
max-n-of number agentset [reporter]
Reports an agentset containing number agents from
agentset with the highest values of reporter. The
agentset is built by finding all the agents with the highest
value of reporter, if there are not number agents
with that value then agents with the second highest value are
found, and so on. At the end, if there is a tie that would make
the resulting agentset too large, the tie is broken randomly.
;; assume the world is 11 x 11
show max-n-of 5 patches [pxcor]
;; shows 5 patches with pxcor = max-pxcor
show max-n-of 5 patches with [pycor = 0] [pxcor]
;; shows an agentset containing:
;; (patch 1 0) (patch 2 0) (patch 3 0) (patch 4 0) (patch 5 0)
See also max-one-of, with-max.
max-one-of agentset [reporter]
Reports the agent in the agentset that has the highest value for
the given reporter. If there is a tie this command reports one
random agent with the highest value. If you want all such agents,
use with-max instead.
show max-one-of patches [count turtles-here]
;; prints the first patch with the most turtles on it
See also max-n-of, with-max.
max-pxcor
max-pycor
These reporters give the maximum x-coordinate and maximum
y-coordinate, (respectively) for patches, which determines the
size of the world.
Unlike in older versions of NetLogo the origin does not have to
be at the center of the world. However, the maximum x- and y-
coordinates must be greater than or equal to zero.
Note: You can set the size of the world only by editing the view
-- these are reporters which cannot be set.
crt 100 [ setxy random-float max-pxcor
random-float max-pycor ]
;; distributes 100 turtles randomly in the
;; first quadrant
See also min-pxcor, min-pycor, world-width, and world-height
mean list
Reports the statistical mean of the numeric items in the given
list. Errors on non-numeric items. The mean is the average, i.e.,
the sum of the items divided by the total number of items.
show mean [xcor] of turtles
;; prints the average of all the turtles' x coordinates
median list
Reports the statistical median of the numeric items of the given
list. Ignores non-numeric items. The median is the item that
would be in the middle if all the items were arranged in order.
(If two items would be in the middle, the median is the average
of the two.)
show median [xcor] of turtles
;; prints the median of all the turtles' x coordinates
member? value list
member? string1 string2
member? agent agentset
For a list, reports true if the given value appears in the given
list, otherwise reports false.
For a string, reports true or false depending on whether
string1 appears anywhere inside string2 as a
substring.
For an agentset, reports true if the given agent is appears in
the given agentset, otherwise reports false.
show member? 2 [1 2 3]
=> true
show member? 4 [1 2 3]
=> false
show member? "bat" "abate"
=> true
show member? turtle 0 turtles
=> true
show member? turtle 0 patches
=> false
See also position.
min list
Reports the minimum number value in the list. It ignores other
types of items.
show min [xcor] of turtles
;; prints the lowest x-coordinate of all the turtles
show min list a b
;; prints the smaller of the two variables a and b
show min (list a b c)
;; prints the smallest of the three variables a, b, and c
min-n-of number agentset [reporter]
Reports an agentset containing number agents from
agentset with the lowest values of reporter. The
agentset is built by finding all the agents with the lowest value
of reporter, if there are not number agents with
that value then the agents with the second lowest value are
found, and so on. At the end, if there is a tie that would make
the resulting agentset too large, the tie is broken randomly.
;; assume the world is 11 x 11
show min-n-of 5 patches [pxcor]
;; shows 5 patches with pxcor = min-pxcor
show min-n-of 5 patches with [pycor = 0] [pxcor]
;; shows an agentset containing:
;; (patch -5 0) (patch -4 0) (patch -3 0) (patch -2 0) (patch -1 0)
See also min-one-of, with-min.
min-one-of agentset [reporter]
Reports a random agent in the agentset that reports the lowest
value for the given reporter. If there is a tie, this command
reports one random agent that meets the condition. If you want
all such agents use with-min instead.
show min-one-of turtles [xcor + ycor]
;; reports the first turtle with the smallest sum of
;; coordinates
See also with-min, min-n-of.
min-pxcor
min-pycor
These reporters give the minimum x-coordinate and minimum
y-coordinate, (respectively) for patches, which determines the
size of the world.
Unlike in older versions of NetLogo the origin does not have to
be at the center of the world. However, the minimum x- and y-
coordinates must be less than or equal to zero.
Note: You can set the size of the world only by editing the view
-- these are reporters which cannot be set.
crt 100 [ setxy random-float min-pxcor
random-float min-pycor ]
;; distributes 100 turtles randomly in the
;; third quadrant
See also max-pxcor, max-pycor, world-width, and world-height
number1 mod number2
Reports number1 modulo number2: that is, the
residue of number1 (mod number2). mod is is
equivalent to the following NetLogo code:
number1 - (floor (number1 / number2)) * number2
Note that mod is "infix", that is, it comes between its
two inputs.
show 62 mod 5
=> 2
show -8 mod 3
=> 1
See also remainder. mod and remainder
behave the same for positive numbers, but differently for
negative numbers.
modes list
Reports a list of the most common item or items in list.
The input list may contain any NetLogo values.
If the input is an empty list, reports an empty list.
show modes [1 2 2 3 4]
=> [2]
show modes [1 2 2 3 3 4]
=> [2 3]
show modes [ [1 2 [3]] [1 2 [3]] [2 3 4] ]
=> [[1 2 [3]]]
show modes [pxcor] of turtles
;; shows which columns of patches have the most
;; turtles on them
mouse-down?
Reports true if the mouse button is down, false otherwise.
Note: If the mouse pointer is outside of the current view ,
mouse-down? will always report false.
mouse-inside?
Reports true if the mouse pointer is inside the current view,
false otherwise.
mouse-xcor
mouse-ycor
Reports the x or y coordinate of the mouse in the 2D view. The
value is in terms of turtle coordinates, so it might not be an
integer. If you want patch coordinates, use round
mouse-xcor and round mouse-ycor.
Note: If the mouse is outside of the 2D view, reports the value
from the last time it was inside.
;; to make the mouse "draw" in red:
if mouse-down?
[ ask patch mouse-xcor mouse-ycor [ set pcolor red ] ]
move-to agent
The turtle sets its x and y coordinates to be the same as the
given agent's.
(If that agent is a patch, the effect is to move the turtle to
the center of that patch.)
move-to turtle 5
;; turtle moves to same point as turtle 5
move-to one-of patches
;; turtle moves to the center of a random patch
move-to max-one-of turtles [size]
;; turtle moves to same point as biggest turtle
Note that the turtle's heading is unaltered. You may want to
use the face command first to orient the
turtle in the direction of motion.
See also setxy.
my-<breeds>
my-links
Reports an agentset of all links connected to the caller of
the corresponding breed, regardless of directedness.
Generally, you might consider using
my-out-links instead
of this primitive, as it works well for either directed or
undirected networks (since it excludes directed, incoming
links).
crt 5
ask turtle 0
[
create-links-with other turtles
show my-links ;; prints the agentset containing all links
;; (since all the links we created were with turtle 0 )
]
ask turtle 1
[
show my-links ;; shows an agentset containing the link 0 1
]
end
If you only want the undirected links connected to a node, you
can do
my-links with [ not is-directed-link? self ].
my-in-<breeds>
my-in-links
Reports an agentset of all the directed links coming in from
other nodes to the caller as well as all undirected links
connected to the caller. You can think of this as "all links
that you can use to travel to this node".
crt 5
ask turtle 0
[
create-links-to other turtles
show my-in-links ;; shows an empty agentset
]
ask turtle 1
[
show my-in-links ;; shows an agentset containing the link 0 1
]
my-out-<breeds>
my-out-links
Reports an agentset of all the directed links going out from the
caller to other nodes as well as undirected links connected to the
caller. You can think of this as "all links you can use to travel
from this node".
crt 5
ask turtle 0
[
create-links-to other turtles
show my-out-links ;; shows agentset containing all the links
]
ask turtle 1
[
show my-out-links ;; shows an empty agentset
]
myself
"self" and "myself" are very different.
"self" is simple; it means "me".
"myself" means "the turtle, patch or link who asked me
to do what I'm doing right now."
When an agent has been asked to run some code, using myself in
that code reports the agent (turtle, patch or link) that did the
asking.
myself is most often used in conjunction with of to read
or set variables in the asking agent.
myself can be used within blocks of code not just in the ask
command, but also hatch, sprout, of, with, all?, with-min,
with-max, min-one-of, max-one-of, min-n-of, max-n-of.
ask turtles
[ ask patches in-radius 3
[ set pcolor [color] of myself ] ]
;; each turtle makes a colored "splotch" around itself
See the "Myself Example" code example for more
examples.
See also self.
n-of size agentset
n-of size list
From an agentset, reports an agentset of size size
randomly chosen from the input set, with no repeats.
From a list, reports a list of size size randomly chosen
from the input set, with no repeats. The items in the result
appear in the same order that they appeared in the input list.
(If you want them in random order, use shuffle on the result.)
It is an error for size to be greater than the size of the
input.
ask n-of 50 patches [ set pcolor green ]
;; 50 randomly chosen patches turn green
See also one-of.
n-values size reporter
Reports a list of length size containing values computed
by repeatedly running the reporter. reporter may be an anonymous
reporter or the name of a reporter.
If the reporter accepts inputs, the input will be the number of the
item currently being computed, starting from zero.
show n-values 5 [1]
=> [1 1 1 1 1]
show n-values 5 [ i -> i ]
=> [0 1 2 3 4]
show n-values 3 turtle
=> [(turtle 0) (turtle 1) (turtle 2)]
show n-values 5 [ x -> x * x ]
=> [0 1 4 9 16]
See also reduce, filter, -> (anonymous procedure), range.
neighbors
neighbors4
Reports an agentset containing the 8 surrounding patches
(neighbors) or 4 surrounding patches (neighbors4).
show sum [count turtles-here] of neighbors
;; prints the total number of turtles on the eight
;; patches around this turtle or patch
show count turtles-on neighbors
;; a shorter way to say the same thing
ask neighbors4 [ set pcolor red ]
;; turns the four neighboring patches red
<breed>-neighbors
link-neighbors
Reports the agentset of all turtles found at the other end of
any links (undirected or directed, incoming or outgoing)
connected to this turtle.
crt 3
ask turtle 0
[
create-links-with other turtles
ask link-neighbors [ set color red ] ;; turtles 1 and 2 turn red
]
ask turtle 1
[
ask link-neighbors [ set color blue ] ;; turtle 0 turns blue
]
end
<breed>-neighbor? turtle
link-neighbor? turtle
Reports true if there is a link (either directed or undirected,
incoming or outgoing) between turtle and the caller.
crt 2
ask turtle 0
[
create-link-with turtle 1
show link-neighbor? turtle 1 ;; prints true
]
ask turtle 1
[
show link-neighbor? turtle 0 ;; prints true
]
netlogo-version
Reports a string containing the version number of the NetLogo you
are running.
show netlogo-version
=> "6.0.4"
netlogo-web?
Reports true if the model is running in NetLogo Web.
new-seed
Reports a number suitable for seeding the random number generator.
The numbers reported by new-seed are based on the current date and
time in milliseconds and lie in the generator's usable range of
seeds, -2147483648 to 2147483647.
new-seed never reports the same number twice in succession, even
across parallel BehaviorSpace runs. (This
is accomplished by waiting a millisecond if the seed for the
current millisecond was already used.)
See also random-seed.
no-display
Turns off all updates to the current view until the display command
is issued. This has two major uses.
One, you can control when the user sees view updates. You might
want to change lots of things on the view behind the user's
back, so to speak, then make them visible to the user all at once.
Two, your model will run faster when view updating is off, so if
you're in a hurry, this command will let you get results
faster. (Note that normally you don't need to use no-display
for this, since you can also use the on/off switch in view control
strip to freeze the view.)
Note that display and no-display operate independently of the
switch in the view control strip that freezes the view.
See also display.
nobody
This is a special value which some primitives such as turtle,
one-of, max-one-of, etc. report to indicate that no agent was
found. Also, when a turtle dies, it becomes equal to nobody.
Note: Empty agentsets are not equal to nobody. If you want to test
for an empty agentset, use any?. You only get
nobody back in situations where you were expecting a single agent,
not a whole agentset.
set target one-of other turtles-here
if target != nobody
[ ask target [ set color red ] ]
no-links
Reports an empty link agentset.
no-patches
Reports an empty patch agentset.
not boolean
Reports true if boolean is false, otherwise reports false.
if not any? turtles [ crt 10 ]
no-turtles
Reports an empty turtle agentset.
[reporter] of agent
[reporter] of agentset
For an agent, reports the value of the reporter for that agent
(turtle or patch).
show [pxcor] of patch 3 5
;; prints 3
show [pxcor] of one-of patches
;; prints the value of a random patch's pxcor variable
show [who * who] of turtle 5
=> 25
show [count turtles in-radius 3] of patch 0 0
;; prints the number of turtles located within a
;; three-patch radius of the origin
For an agentset, reports a list that contains the value of the
reporter for each agent in the agentset (in random order).
crt 4
show sort [who] of turtles
=> [0 1 2 3]
show sort [who * who] of turtles
=> [0 1 4 9]
one-of agentset
one-of list
From an agentset, reports a random agent. If the agentset is empty,
reports nobody.
From a list, reports a random list item. It is an error for the
list to be empty.
ask one-of patches [ set pcolor green ]
;; a random patch turns green
ask patches with [any? turtles-here]
[ show one-of turtles-here ]
;; for each patch containing turtles, prints one of
;; those turtles
;; suppose mylist is [1 2 3 4 5 6]
show one-of mylist
;; prints a value randomly chosen from the list
See also n-of.
boolean1 or boolean2
Reports true if either boolean1 or boolean2, or both,
is true.
Note that if condition1 is true, then condition2 will
not be run (since it can't affect the result).
if (pxcor > 0) or (pycor > 0) [ set pcolor red ]
;; patches turn red except in lower-left quadrant
other agentset
Reports an agentset which is the same as the input agentset but
omits this agent.
show count turtles-here
=> 10
show count other turtles-here
=> 9
other-end
If run by a turtle, reports the turtle at the other end of the
asking link.
If run by a link, reports the turtle at the end of the link that
isn't the asking turtle.
These definitions are difficult to understand in the abstract, but
the following examples should help:
ask turtle 0 [ create-link-with turtle 1 ]
ask turtle 0 [ ask link 0 1 [ show other-end ] ] ;; prints turtle 1
ask turtle 1 [ ask link 0 1 [ show other-end ] ] ;; prints turtle 0
ask link 0 1 [ ask turtle 0 [ show other-end ] ] ;; prints turtle 1
As these examples hopefully make plain, the "other" end
is the end that is neither asking nor being asked.
out-<breed>-neighbor? turtle
out-link-neighbor? turtle
Reports true if there is a directed link going from the caller to
turtle or if there is an undirected link connecting the caller
with turtle. You can think of this as "can I get from the caller
to turtle using a link?"
crt 2
ask turtle 0 [
create-link-to turtle 1
show in-link-neighbor? turtle 1 ;; prints false
show out-link-neighbor? turtle 1 ;; prints true
]
ask turtle 1 [
show in-link-neighbor? turtle 0 ;; prints true
show out-link-neighbor? turtle 0 ;; prints false
]
out-<breed>-neighbors
out-link-neighbors
Reports the agentset of all the turtles that have directed links
from the caller, or undirected links with the caller. You can think
of this as "who can I get to from the caller using a link?"
crt 4
ask turtle 0
[
create-links-to other turtles
ask out-link-neighbors [ set color pink ] ;; turtles 1-3 turn pink
]
ask turtle 1
[
ask out-link-neighbors [ set color orange ] ;; no turtles change colors
;; since turtle 1 only has in-links
]
end
out-<breed>-to turtle
out-link-to turtle
Reports a directed link from the caller to turtle or an
undirected link connecting the two. If no link exists then it
reports nobody. If more than one such link exists, reports a
random one. You can think of this as "give me a link that I can use
to travel from the caller to turtle."
crt 2
ask turtle 0 [
create-link-to turtle 1
show out-link-to turtle 1 ;; shows link 0 1
]
ask turtle 1
[
show out-link-to turtle 0 ;; shows nobody
]
See also: in-link-from link-with
output-print value
output-show value
output-type value
output-write value
These commands are the same as the print,
show, type, and write commands except that value is printed in
the model's output area, instead of in the Command Center. (If
the model does not have a separate output area, then the Command
Center is used.) See also Output (programming guide).
patch xcor ycor
Given the x and y coordinates of a point, reports the patch
containing that point. (The coordinates are absolute coordinates;
they are not computed relative to this agent, as with patch-at.)
If x and y are integers, the point is the center of a patch. If x
or y is not an integer, rounding to the nearest integer is used to
determine which patch contains the point.
If wrapping is allowed by the topology, the given coordinates will
be wrapped to be within the world. If wrapping is not allowed and
the given coordinates are outside the world, reports nobody.
ask patch 3 -4 [ set pcolor green ]
;; patch with pxcor of 3 and pycor of -4 turns green
show patch 1.2 3.7
;; prints (patch 1 4); note rounding
show patch 18 19
;; supposing min-pxcor and min-pycor are -17
;; and max-pxcor and max-pycor are 17,
;; in a wrapping topology, prints (patch -17 -16);
;; in a non-wrapping topology, prints nobody
See also patch-at.
patch-ahead distance
Reports the single patch that is the given distance
"ahead" of this turtle, that is, along the turtle's
current heading. Reports nobody if the patch does not exist because
it is outside the world.
ask patch-ahead 1 [ set pcolor green ]
;; turns the patch 1 in front of this turtle
;; green; note that this might be the same patch
;; the turtle is standing on
See also patch-at, patch-left-and-ahead, patch-right-and-ahead, patch-at-heading-and-distance.
patch-at dx dy
Reports the patch at (dx, dy) from the caller, that is, the patch
containing the point dx east and dy patches north of this agent.
Reports nobody if there is no such patch because that point is
beyond a non-wrapping world boundary.
ask patch-at 1 -1 [ set pcolor green ]
;; if caller is a turtle or patch, turns the
;; patch just southeast of the caller green
See also patch, patch-ahead, patch-left-and-ahead, patch-right-and-ahead, patch-at-heading-and-distance.
patch-at-heading-and-distance heading distance
patch-at-heading-and-distance reports the single patch that is the
given distance from this turtle or patch, along the given absolute
heading. (In contrast to patch-left-and-ahead and
patch-right-and-ahead, this turtle's current heading is not
taken into account.) Reports nobody if the patch does not exist
because it is outside the world.
ask patch-at-heading-and-distance -90 1 [ set pcolor green ]
;; turns the patch 1 to the west of this patch green
See also patch, patch-at, patch-left-and-ahead, patch-right-and-ahead.
patch-here
patch-here reports the patch under the turtle.
Note that this reporter isn't available to a patch because a
patch can just say "self".
patch-left-and-ahead angle distance
patch-right-and-ahead angle distance
Reports the single patch that is the given distance from this
turtle, in the direction turned left or right the given angle (in
degrees) from the turtle's current heading. Reports nobody if
the patch does not exist because it is outside the world.
(If you want to find a patch in a given absolute heading, rather
than one relative to the current turtle's heading, use
patch-at-heading-and-distance instead.)
ask patch-right-and-ahead 30 1 [ set pcolor green ]
;; this turtle "looks" 30 degrees right of its
;; current heading at the patch 1 unit away, and turns
;; that patch green; note that this might be the same
;; patch the turtle is standing on
See also patch, patch-at, patch-at-heading-and-distance.
patch-set value1
(patch-set value1 value2 ...)
Reports an agentset containing all of the patches anywhere in any
of the inputs. The inputs may be individual patches, patch
agentsets, nobody, or lists (or nested lists) containing any of the
above.
patch-set self
patch-set patch-here
(patch-set self neighbors)
(patch-set patch-here neighbors)
(patch-set patch 0 0 patch 1 3 patch 4 -2)
(patch-set patch-at -1 1 patch-at 0 1 patch-at 1 1)
patch-set [patch-here] of turtles
patch-set [neighbors] of turtles
See also turtle-set, link-set.
patch-size
Reports the size of the patches in the view in pixels. The size is
typically an integer, but may also be a floating point number.
See also set-patch-size.
patches
Reports the agentset consisting of all patches.
patches-own [var1 ...]
This keyword, like the globals, breed, <breed>-own,
and turtles-own keywords, can only be used at the beginning of a
program, before any function definitions. It defines the variables
that all patches can use.
All patches will then have the given variables and be able to use
them.
All patch variables can also be directly accessed by any turtle
standing on the patch.
See also globals, turtles-own, breed,
<breeds>-own.
pcolor
This is a built-in patch variable. It holds the color of the patch.
You can set this variable to make the patch change color.
All patch variables can be directly accessed by any turtle standing
on the patch. Color can be represented either as a NetLogo color (a
single number) or an RGB color (a list of 3 numbers). See details
in the Colors section of the
Programming Guide.
See also color.
pen-down
pen-erase
pen-up
The turtle changes modes between drawing lines, removing lines or
neither. The lines will always be displayed on top of the patches
and below the turtles. To change the color of the pen set the color
of the turtle using set color.
Note: When a turtle's pen is down, all movement commands cause
lines to be drawn, including jump, setxy, and move-to.
Note: These commands are equivalent to setting the turtle variable
"pen-mode" to "down" , "up", and
"erase".
Note: On Windows drawing and erasing a line might not erase every
pixel.
This is a built-in turtle variable. It holds the state of the
turtle's pen. You set the variable to draw lines, erase lines
or stop either of these actions. Possible values are
"up", "down", and "erase".
This is a built-in turtle variable. It holds the width of the line,
in pixels, that the turtle will draw (or erase) when the pen is
down (or erasing).
plabel
This is a built-in patch variable. It may hold a value of any type.
The patch appears in the view with the given value
"attached" to it as text. You can set this variable to
add, change, or remove a patch's label.
All patch variables can be directly accessed by any turtle standing
on the patch.
See also plabel-color, label, label-color.
plabel-color
This is a built-in patch variable. It holds a number greater than
or equal to 0 and less than 140. This number determines what color
the patch's label appears in (if it has a label). You can set
this variable to change the color of a patch's label.
All patch variables can be directly accessed by any turtle standing
on the patch.
See also plabel, label,
label-color.
plot number
Increments the x-value of the plot pen by plot-pen-interval, then
plots a point at the updated x-value and a y-value of
number. (The first time the command is used on a plot, the
point plotted has an x-value of 0.)
plot-name
Reports the name of the current plot (a string)
plot-pen-exists? string
Reports true if a plot pen with the given name is defined in the
current plot. Otherwise reports false.
plot-pen-down
plot-pen-up
Puts down (or up) the current plot-pen, so that it draws (or
doesn't). (By default, all pens are down initially.)
plot-pen-reset
Clears everything the current plot pen has drawn, moves it to
(0,0), and puts it down. If the pen is a permanent pen, the color,
mode, and interval are reset to the default values from the plot
Edit dialog.
plotxy number1 number2
Moves the current plot pen to the point with coordinates
(number1, number2). If the pen is down, a line, bar,
or point will be drawn (depending on the pen's mode).
plot-x-min
plot-x-max
plot-y-min
plot-y-max
Reports the minimum or maximum value on the x or y axis of the
current plot.
These values can be set with the commands set-plot-x-range and
set-plot-y-range. (Their default values are set from the plot Edit
dialog.)
position item list
position string1 string2
On a list, reports the first position of item in
list, or false if it does not appear.
On strings, reports the position of the first appearance
string1 as a substring of string2, or false if it
does not appear.
Note: The positions are numbered beginning with 0, not with 1.
;; suppose mylist is [2 7 4 7 "Bob"]
show position 7 mylist
=> 1
show position 10 mylist
=> false
show position "in" "string"
=> 3
See also member?.
precision number places
Reports number rounded to places decimal places.
If places is negative, the rounding takes place to the left
of the decimal point.
show precision 1.23456789 3
=> 1.235
show precision 3834 -3
=> 4000
See also round, ceiling, floor.
print value
Prints value in the Command Center, followed by a carriage
return.
This agent is not printed before the value, unlike show.
See also show, type,
write, output-print, and
Output (programming guide).
pxcor
pycor
These are built-in patch variables. They hold the x and y
coordinate of the patch. They are always integers. You cannot set
these variables, because patches don't move.
pxcor is greater than or equal to min-pxcor and less than or equal
to max-pxcor; similarly for pycor and min-pycor and max-pycor.
All patch variables can be directly accessed by any turtle standing
on the patch.
See also xcor, ycor.
random number
If number is positive, reports a random integer greater than
or equal to 0, but strictly less than number.
If number is negative, reports a random integer less than or
equal to 0, but strictly greater than number.
If number is zero, the result is always 0 as well.
Note: In versions of NetLogo prior to version 2.0, this primitive
reported a floating point number if given a non-integer input. This
is no longer the case. If you want a floating point answer, you
must now use random-float instead.
show random 3
;; prints 0, 1, or 2
show random -3
;; prints 0, -1, or -2
show random 3.5
;; prints 0, 1, 2, or 3
See also random-float.
random-float number
If number is positive, reports a random floating point
number greater than or equal to 0 but strictly less than
number.
If number is negative, reports a random floating point
number less than or equal to 0, but strictly greater than
number.
If number is zero, the result is always 0.
show random-float 3
;; prints a number at least 0 but less than 3,
;; for example 2.589444906014774
show random-float 2.5
;; prints a number at least 0 but less than 2.5,
;; for example 1.0897423196760796
random-exponential mean
random-gamma alpha lambda
random-normal mean standard-deviation
random-poisson mean
Reports an accordingly distributed random number with the
mean and, in the case of the normal distribution, the
standard-deviation. (The standard deviation may not be
negative.)
random-exponential reports an exponentially distributed random
floating point number. It is equivalent to (- mean) * ln
random-float 1.0.
random-gamma reports a gamma-distributed random floating point
number as controlled by the floating point alpha and lambda
parameters. Both inputs must be greater than zero. (Note: for
results with a given mean and variance, use inputs as follows:
alpha = mean * mean / variance; lambda = 1 / (variance / mean).)
random-normal reports a normally distributed random floating point
number.
random-poisson reports a Poisson-distributed random integer.
show random-exponential 2
;; prints an exponentially distributed random floating
;; point number with a mean of 2
show random-normal 10.1 5.2
;; prints a normally distributed random floating point
;; number with a mean of 10.1 and a standard deviation
;; of 5.2
show random-poisson 3.4
;; prints a Poisson-distributed random integer with a
;; mean of 3.4
random-pxcor
random-pycor
Reports a random integer ranging from min-pxcor (or -y) to
max-pxcor (or -y) inclusive.
ask turtles [
;; move each turtle to the center of a random patch
setxy random-pxcor random-pycor
]
See also random-xcor, random-ycor.
random-seed number
Sets the seed of the pseudo-random number generator to the integer
part of number. The seed must be in the range -2147483648 to
2147483647; note that this is smaller than the full range of
integers supported by NetLogo (-9007199254740992 to
9007199254740992).
See the Random Numbers
section of the Programming Guide for more details.
random-seed 47822
show random 100
=> 50
show random 100
=> 35
random-seed 47822
show random 100
=> 50
show random 100
=> 35
random-xcor
random-ycor
Reports a random floating point number from the allowable range of
turtle coordinates along the given axis, x or y.
Turtle coordinates range from min-pxcor - 0.5 (inclusive) to
max-pxcor + 0.5 (exclusive) horizontally; vertically, substitute -y
for -x.
ask turtles [
;; move each turtle to a random point
setxy random-xcor random-ycor
]
See also random-pxcor, random-pycor.
range stop
(range start stop)
(range start stop step)
Generates a list of numbers, starting at start, ending before
stop, counting by step. start defaults to 0 and
step defaults to 1.
show range 5
=> [0 1 2 3 4]
show (range 2 5)
=> [2 3 4]
show (range 2 5 0.5)
=> [2 2.5 3 3.5 4 4.5]
show (range 10 0 -1)
=> [10 9 8 7 6 5 4 3 2 1]
See also n-values
read-from-string string
Interprets the given string as if it had been typed in the Command
Center, and reports the resulting value. The result may be a
number, list, string, or boolean value, or the special value
"nobody".
Useful in conjunction with the user-input
primitive for converting the user's input into usable form.
show read-from-string "3" + read-from-string "5"
=> 8
show length read-from-string "[1 2 3]"
=> 3
crt read-from-string user-input "Make how many turtles?"
;; the number of turtles input by the user
;; are created
reduce reporter list
Reduces a list from left to right using the given reporter, resulting
in a single value. This means, for example, that reduce
[ [a b] -> a + b] [1 2 3 4]
is equivalent to (((1 + 2) + 3) + 4). If
list has a single item, that item is reported. It is an
error to reduce an empty list. reporter may be an anonymous
reporter or the name of a reporter.
The first input passed to the reporter is the result so far, and the
second input is the next item in the list.
Since it can be difficult to develop an intuition about what
reduce does, here are some simple examples which, while
not useful in themselves, may give you a better understanding of
this primitive:
show reduce + [1 2 3]
=> 6
show reduce - [1 2 3]
=> -4
show reduce [ [result-so-far next-item] -> next-item - result-so-far ] [1 2 3]
=> 2
show reduce [ [result-so-far ignored-item] -> result-so-far ] [1 2 3]
=> 1
show reduce [ [ignored next-item] -> next-item ] [1 2 3]
=> 3
show reduce sentence [[1 2] [3 [4]] 5]
=> [1 2 3 [4] 5]
show reduce [ [result-so-far next-item] -> fput next-item result-so-far ] (fput [] [1 2 3 4 5])
=> [5 4 3 2 1]
Here are some more useful examples:
;; find the longest string in a list
to-report longest-string [strings]
report reduce
[ [longest-so-far next-string] -> ifelse-value (length longest-so-far >= length next-string) [longest-so-far] [next-string] ]
strings
end
show longest-string ["hi" "there" "!"]
=> "there"
;; count the number of occurrences of an item in a list
to-report occurrences [x the-list]
report reduce
[ [occurrence-count next-item] -> ifelse-value (next-item = x) [occurrence-count + 1] [occurrence-count] ] (fput 0 the-list)
end
show occurrences 1 [1 2 1 3 1 2 3 1 1 4 5 1]
=> 6
;; evaluate the polynomial, with given coefficients, at x
to-report evaluate-polynomial [coefficients x]
report reduce [ [value coefficient] -> (x * value) + coefficient ] coefficients
end
;; evaluate 3x^2 + 2x + 1 at x = 4
show evaluate-polynomial [3 2 1] 4
=> 57
See also filter, -> (anonymous procedure.
remainder number1 number2
Reports the remainder when number1 is divided by
number2. This is equivalent to the following NetLogo code:
number1 - (int (number1 / number2)) * number2
show remainder 62 5
=> 2
show remainder -8 3
=> -2
See also mod. mod and remainder behave the same
for positive numbers, but differently for negative numbers.
remove item list
remove string1 string2
For a list, reports a copy of list with all instances of
item removed.
For strings, reports a copy of string2 with all the
appearances of string1 as a substring removed.
set mylist [2 7 4 7 "Bob"]
set mylist remove 7 mylist
;; mylist is now [2 4 "Bob"]
show remove "to" "phototonic"
=> "phonic"
remove-duplicates list
Reports a copy of list with all duplicate items removed. The
first of each item remains in place.
set mylist [2 7 4 7 "Bob" 7]
set mylist remove-duplicates mylist
;; mylist is now [2 7 4 "Bob"]
remove-item index list
remove-item index string
For a list, reports a copy of list with the item at the
given index removed.
For strings, reports a copy of string with the character at
the given index removed.
Note that the indices begin from 0, not 1. (The first item is item
0, the second item is item 1, and so on.)
set mylist [2 7 4 7 "Bob"]
set mylist remove-item 2 mylist
;; mylist is now [2 7 7 "Bob"]
show remove-item 2 "string"
=> "sting"
repeat number [ commands ]
Runs commands number times.
pd repeat 36 [ fd 1 rt 10 ]
;; the turtle draws a circle
replace-item index list value
replace-item index string1 string2
On a list, replaces an item in that list. index is the index
of the item to be replaced, starting with 0. (The 6th item in a
list would have an index of 5.) Note that "replace-item"
is used in conjunction with "set" to change a list.
Likewise for a string, but the given character of string1
removed and the contents of string2 spliced in instead.
show replace-item 2 [2 7 4 5] 15
=> [2 7 15 5]
show replace-item 1 "cat" "are"
=> "caret"
report value
Immediately exits from the current to-report procedure and reports
value as the result of that procedure. report and to-report
are always used in conjunction with each other. See to-report for a discussion of how to use them.
reset-perspective
The observer stops watching, following, or riding any turtles (or
patches). (If it wasn't watching, following, or riding anybody,
nothing happens.) In the 3D view, the observer also returns to its
default position (above the origin, looking straight down).
See also follow, ride,
watch.
reset-ticks
Resets the tick counter to zero, sets up all plots, then updates
all plots (so that the initial state of the world is plotted).
Normally reset-ticks goes at the end of a setup procedure.
See also clear-ticks, tick, ticks, tick-advance, setup-plots, update-plots.
reset-timer
Resets the timer to zero seconds. See also timer.
Note that the timer is different from the tick counter. The timer
measures elapsed real time in seconds; the tick counter measures
elapsed model time in ticks.
resize-world min-pxcor max-pxcor min-pycor max-pycor
Changes the size of the patch grid.
If the given patch grid coordinates are different than the ones
in use, all turtles and links die, and the existing patch grid is
discarded and new patches created. Otherwise, existing turtles
and links will live if the grid coordinates are unchanged.
Retaining references to old patches or patch sets is inadvisable
and may subsequently cause runtime errors or other unexpected
behavior.
See also set-patch-size.
reverse list
reverse string
Reports a reversed copy of the given list or string.
show mylist
;; mylist is [2 7 4 "Bob"]
set mylist reverse mylist
;; mylist now is ["Bob" 4 7 2]
show reverse "live"
=> "evil"
rgb red green blue
Reports a RGB list when given three numbers describing an RGB
color. The numbers are range checked to be between 0 and 255.
See also hsb
ride turtle
Set the perspective to turtle.
Every time turtle moves the observer also moves. Thus, in
the 2D View the turtle will stay at the center of the view. In the
3D view it is as if looking through the eyes of the turtle. If the
turtle dies, the perspective resets to the default.
The observer may only watch or follow a single subject.
Calling ride will remove the highlight created by
prior calls to watch and watch-me,
highlighting the ridden turtle instead.
See also reset-perspective,
watch, follow, subject.
ride-me
Asks the observer to ride this turtle.
The observer may only watch or follow a single subject.
Calling ride-me will remove the highlight created by
prior calls to watch and watch-me,
highlighting this turtle instead.
See also ride.
right number
The turtle turns right by number degrees. (If number
is negative, it turns left.)
round number
Reports the integer nearest to number.
If the decimal portion of number is exactly .5, the number
is rounded in the positive direction.
Note that rounding in the positive direction is not always how
rounding is done in other software programs. (In particular, it
does not match the behavior of StarLogoT, which always rounded
numbers ending in 0.5 to the nearest even integer.) The rationale
for this behavior is that it matches how turtle coordinates relate
to patch coordinates in NetLogo. For example, if a turtle's
xcor is -4.5, then it is on the boundary between a patch whose
pxcor is -4 and a patch whose pxcor is -5, but the turtle must be
considered to be in one patch or the other, so the turtle is
considered to be in the patch whose pxcor is -4, because we round
towards the positive numbers.
show round 4.2
=> 4
show round 4.5
=> 5
show round -4.5
=> -4
See also precision, ceiling, floor.
run command
(run command input1 ...)
run string
runresult reporter
(runresult reporter input1 ...)
runresult string
The run form expects the name of a command, an anonymous command,
or a string containing commands. This agent then runs them.
The runresult form expects the name of a reporter, an anonymous reporter,
or a string containing a reporter. This agent runs it and reports the result.
Note that you can't use run to define or redefine
procedures. If you care about performance, note that the code must
be compiled first which takes time. However, compiled bits of code
are cached by NetLogo and thus using run on the same
string over and over is much faster than running different strings.
The first run, though, will be many times slower than
running the same code directly, or in an anonymous command.
Anonymous procedures are recommended over strings whenever possible.
(An example of when you must use strings is if you accept pieces
of code from the user of your model.)
Anonymous procedures may freely read and/or set local variables
and procedure inputs. Trying to do the same with strings may
or may not work and should not be relied on.
When using anonymous procedures, you can provide them with inputs,
if you surround the entire call with parentheses. For example:
(run [ [turtle-count step-count] -> crt turtle-count [ fd step-count ] ] 10 5)
;; creates 10 turtles and move them forward 5 steps
show (runresult [ [a b] -> a + b ] 10 5)
=> 15
;; adds 10 and 5
See also foreach, -> (anonymous procedure).
scale-color color number range1 range2
Reports a shade of color proportional to the value of
number.
If range1 is less than range2, then the larger the
number, the lighter the shade of color. But if range2
is less than range1, the color scaling is inverted.
If number is less than range1, then the darkest shade
of color is chosen.
If number is greater than range2, then the lightest
shade of color is chosen.
Note: for color shade is irrelevant, e.g. green and green +
2 are equivalent, and the same spectrum of colors will be used.
ask turtles [ set color scale-color red age 0 50 ]
;; colors each turtle a shade of red proportional
;; to its value for the age variable
self
Reports this turtle, patch, or link.
"self" and "myself" are very different.
"self" is simple; it means "me".
"myself" means "the agent who asked me to do what
I'm doing right now."
Note that it is always redundant to write [foo] of self.
This is always equivalent to simply writing foo.
See also myself.
; comments
After a semicolon, the rest of the line is ignored. This is useful
for adding "comments" to your code -- text that explains
the code to human readers. Extra semicolons can be added for visual
effect.
NetLogo's Edit menu has items that let you comment or uncomment
whole sections of code.
sentence value1 value2
(sentence value1 ...)
Makes a list out of the values. If any value is a list, its items
are included in the result directly, rather than being included as
a sublist. Examples make this clearer:
show sentence 1 2
=> [1 2]
show sentence [1 2] 3
=> [1 2 3]
show sentence 1 [2 3]
=> [1 2 3]
show sentence [1 2] [3 4]
=> [1 2 3 4]
show sentence [[1 2]] [[3 4]]
=> [[1 2] [3 4]]
show (sentence [1 2] 3 [4 5] (3 + 3) 7)
=> [1 2 3 4 5 6 7]
set variable value
Sets variable to the given value.
Variable can be any of the following:
- A global variable declared using "globals"
- The global variable associated with a slider, switch, chooser,
or input box.
- A variable belonging to this agent
- If this agent is a turtle, a variable belonging to the patch
under the turtle.
- A local variable created by the let command.
- An input to the current procedure.
set-current-directory string
Sets the current directory that is used by the primitives file-delete, file-exists?, and file-open.
The current directory is not used if the above commands are given
an absolute file path. This is defaulted to the user's home
directory for new models, and is changed to the model's
directory when a model is opened.
Note that in Windows file paths the backslash needs to be escaped
within a string by using another backslash "C:\\"
The change is temporary and is not saved with the model.
set-current-directory "C:\\NetLogo"
;; Assume it is a Windows Machine
file-open "my-file.txt"
;; Opens file "C:\\NetLogo\\my-file.txt"
set-current-plot plotname
Sets the current plot to the plot with the given name (a string).
Subsequent plotting commands will affect the current plot.
set-current-plot-pen penname
The current plot's current pen is set to the pen named
penname (a string). If no such pen exists in the current
plot, a runtime error occurs.
set-default-shape turtles string
set-default-shape links string
set-default-shape breed string
Specifies a default initial shape for all turtles or links, or for
a particular breed of turtles or links. When a turtle or link is
created, or it changes breeds, it shape is set to the given shape.
This command doesn't affect existing agents, only agents you
create afterwards.
The given breed must be either turtles, links, or the name of a
breed. The given string must be the name of a currently defined
shape.
In new models, the default shape for all turtles is
"default".
Note that specifying a default shape does not prevent you from
changing an agent's shape later. Agents don't have to be
stuck with their breed's default shape.
create-turtles 1 ;; new turtle's shape is "default"
create-cats 1 ;; new turtle's shape is "default"
set-default-shape turtles "circle"
create-turtles 1 ;; new turtle's shape is "circle"
create-cats 1 ;; new turtle's shape is "circle"
set-default-shape cats "cat"
set-default-shape dogs "dog"
create-cats 1 ;; new turtle's shape is "cat"
ask cats [ set breed dogs ]
;; all cats become dogs, and automatically
;; change their shape to "dog"
See also shape.
set-histogram-num-bars number
Set the current plot pen's plot interval so that, given the
current x range for the plot, there would be number number
of bars drawn if the histogram command is called.
See also histogram.
__set-line-thickness number
Specifies the thickness of lines and outlined elements in the
turtle's shape.
The default value is 0. This always produces lines one pixel thick.
Non-zero values are interpreted as thickness in patches. A
thickness of 1, for example, produces lines which appear one patch
thick. (It's common to use a smaller value such as 0.5 or 0.2.)
Lines are always at least one pixel thick.
This command is experimental and may change in later releases.
set-patch-size size
Sets the size of the patches of the view in pixels. The size is
typically an integer, but may also be a floating point number.
See also patch-size, resize-world.
set-plot-background-color color
Sets the background color of the current plot.
The color may be specified as a number or a list.
See the Colors section of the programming guide for more details.
This change is temporary and is not saved with the model. When the
plot is cleared, the background color will revert to white.
Note: Plot backgrounds do not support transparency.
If a list is used to set the color, the alpha component will be ignored.
set-plot-pen-color color
Sets the color of the current plot pen to color.
set-plot-pen-interval number
Tells the current plot pen to move a distance of number in
the x direction during each use of the plot command. (The plot pen
interval also affects the behavior of the histogram command.)
set-plot-pen-mode number
Sets the mode the current plot pen draws in to number. The
allowed plot pen modes are:
- 0 (line mode) the plot pen draws a line connecting two points
together.
- 1 (bar mode): the plot pen draws a bar of width
plot-pen-interval with the point plotted as the upper (or lower, if
you are plotting a negative number) left corner of the bar.
- 2 (point mode): the plot pen draws a point at the point
plotted. Points are not connected.
The default mode for new pens is 0 (line mode).
setup-plots
For each plot, runs that plot's setup commands, including the
setup code for any pens in the plot.
reset-ticks has the same effect, so in
models that use the tick counter, this primitive is not normally
used.
See the Plotting section of
the Programming Guide for more details.
See also update-plots.
set-plot-x-range min max
set-plot-y-range min max
Sets the minimum and maximum values of the x or y axis of the
current plot.
The change is temporary and is not saved with the model. When the
plot is cleared, the ranges will revert to their default values as
set in the plot's Edit dialog.
setxy x y
The turtle sets its x-coordinate to x and its y-coordinate
to y.
Equivalent to set xcor x set ycor y, except it happens in
one time step instead of two.
If x or y is outside the world, NetLogo will throw a
runtime error, unless wrapping is turned on in the relevant
dimensions. For example, with wrapping turned on in both dimensions
and the default world size where min-pxcor = -16,
max-pxcor = 16, min-pycor = -16 and max-pycor
= 16, asking a turtle to setxy 17 17 will move it to
the center of patch (-16, -16).
setxy 0 0
;; turtle moves to the middle of the center patch
setxy random-xcor random-ycor
;; turtle moves to a random point
setxy random-pxcor random-pycor
;; turtle moves to the center of a random patch
See also move-to.
shade-of? color1 color2
Reports true if both colors are shades of one another, false
otherwise.
show shade-of? blue red
=> false
show shade-of? blue (blue + 1)
=> true
show shade-of? gray white
=> true
shape
This is a built-in turtle and link variable. It holds a string that
is the name of the turtle or link's current shape. You can set
this variable to change the shape. New turtles and links have the
shape "default" unless the a different shape has been
specified using set-default-shape.
Example:
ask turtles [ set shape "wolf" ]
;; assumes you have made a "wolf"
;; shape in NetLogo's Turtle Shapes Editor
ask links [ set shape "link 1" ]
;; assumes you have made a "link 1" shape in
;; the Link Shapes Editor
See also set-default-shape,
shapes.
shapes
Reports a list of strings containing all of the turtle shapes in
the model.
New shapes can be created, or imported from the shapes library or
from other models, in the Shapes Editor.
show shapes
=> ["default" "airplane" "arrow" "box" "bug" ...
ask turtles [ set shape one-of shapes ]
show value
Prints value in the Command Center, preceded by this agent,
and followed by a carriage return. (This agent is included to help
you keep track of what agents are producing which lines of output.)
Also, all strings have their quotes included similar to write.
See also print, type,
write, output-show,
and Output (programming guide).
show-turtle
The turtle becomes visible again.
Note: This command is equivalent to setting the turtle variable
"hidden?" to false.
See also hide-turtle.
show-link
The link becomes visible again.
Note: This command is equivalent to setting the link variable
"hidden?" to false.
See also hide-link.
shuffle list
Reports a new list containing the same items as the input list, but
in randomized order.
show shuffle [1 2 3 4 5]
=> [5 2 4 1 3]
show shuffle [1 2 3 4 5]
=> [1 3 5 2 4]
sin number
Reports the sine of the given angle. Assumes angle is given in
degrees.
show sin 270
=> -1
size
This is a built-in turtle variable. It holds a number that is the
turtle's apparent size. The default size is 1, which means that
the turtle is the same size as a patch. You can set this variable
to change a turtle's size.
sort list
sort agentset
Reports a sorted list of numbers, strings, or agents.
If the input contains no numbers, strings, or agents, the result is
the empty list.
If the input contains at least one number, the numbers in the list
are sorted in ascending order and a new list reported; non-numbers
are ignored.
Or, if the input contains at least one string, the strings in the
list are sorted in ascending order and a new list reported;
non-strings are ignored.
Or, if the input is an agentset or a list containing at least one
agent, a sorted list of agents (never an agentset) is reported;
non-agents are ignored. Agents are sorted in the same order the
< operator uses. (Patches are sorted with the top left-most patch first
and the bottom right-most patch last, turtles are sorted by who
number).
show sort [3 1 4 2]
=> [1 2 3 4]
show sort [2 1 "a"]
=> [1 2]
show sort (list "a" "c" "b" (patch 0 0))
=> ["a" "b" "c"]
show sort (list (patch 0 0) (patch 0 1) (patch 1 0))
=> [(patch 0 1) (patch 0 0) (patch 1 0)]
;; label patches with numbers in left-to-right, top-to-bottom order
let n 0
foreach sort patches [ the-patch ->
ask the-patch [
set plabel n
set n n + 1
]
]
;; some additional examples to clarify behavior in strange cases
show sort (list patch 0 0 patch 0 1 patch 1 0 turtle 0 turtle 1) ; turtles are always sorted lower than patches
=> [(turtle 0) (turtle 1) (patch 0 1) (patch 0 0) (patch 1 0)]
show sort (list nobody false true) ; booleans and nobody cannot be sorted
=> []
show sort (list [1 2 3] turtles) ; lists and agentsets are not included if they are inside a list passed to sort
=> []
See also sort-by, sort-on.
sort-by reporter list
sort-by reporter agentset
If the input is a list, reports a new list containing the same
items as the input list, in a sorted order defined by the boolean
reporter. reporter may be an anonymous reporter or
the name of a reporter.
The two inputs to reporter are the values being compared.
The reporter should report true if the first argument comes strictly before
the second in the desired sort order, and false otherwise.
If the input is an agentset or a list of agents, reports a list
(never an agentset) of agents.
If the input is a list, the sort is stable, that is, the order of
items considered equal by the reporter is not disturbed. If the
input is an agentset, ties are broken randomly.
show sort-by < [3 1 4 2]
=> [1 2 3 4]
show sort-by > [3 1 4 2]
=> [4 3 2 1]
show sort-by [ [string1 string2] -> length string1 < length string2 ] ["Grumpy" "Doc" "Happy"]
=> ["Doc" "Happy" "Grumpy"]
See also sort, sort-on, -> (anonymous procedure).
sort-on [reporter] agentset
Reports a list of agents, sorted according to each agent's
value for reporter. Ties are broken randomly.
The values must be all numbers, all strings, or all agents of the
same type.
crt 3
show sort-on [who] turtles
=> [(turtle 0) (turtle 1) (turtle 2)]
show sort-on [(- who)] turtles
=> [(turtle 2) (turtle 1) (turtle 0)]
foreach sort-on [size] turtles
[ the-turtle -> ask the-turtle [ do-something ] ]
;; turtles run "do-something" one at a time, in
;; ascending order by size
See also sort, sort-by.
sprout number [ commands ]
sprout-<breeds> number [ commands ]
Creates number new turtles on the current patch. The new
turtles have random integer headings and the color is randomly
selected from the 14 primary colors. The turtles immediately run
commands. This is useful for giving the new turtles
different colors, headings, or whatever. (The new turtles are
created all at once then run one at a time, in random order.)
If the sprout-<breeds> form is used, the new turtles
are created as members of the given breed.
sprout 5
sprout-wolves 10
sprout 1 [ set color red ]
sprout-sheep 1 [ set color black ]
See also create-turtles, hatch.
sqrt number
Reports the square root of number.
stamp
This turtle or link leaves an image of its shape in the drawing at
its current location.
Note: The shapes made by stamp may not be pixel-for-pixel identical
from computer to computer.
stamp-erase
This turtle or link removes any pixels below it in the drawing
inside the bounds of its shape.
Note: The shapes made by stamp-erase may not be pixel-for-pixel
identical from computer to computer.
standard-deviation list
Reports the sample standard deviation of a list of numbers.
Ignores other types of items.
(Note that this estimates the standard deviation for a
sample, rather than for a whole population, using
Bessel's correction.)
show standard-deviation [1 2 3 4 5 6]
=> 1.8708286933869707
show standard-deviation [energy] of turtles
;; prints the standard deviation of the variable "energy"
;; from all the turtles
startup
User-defined procedure which, if it exists, will be called when a
model is first loaded in the NetLogo application.
to startup
setup
end
startup does not run when a model is run headless from the
command line, or by parallel BehaviorSpace.
stop
This agent exits immediately from the enclosing procedure, ask, or
ask-like construct (e.g. crt, hatch, sprout). Only the enclosing
procedure or construct stops, not all execution for the agent.
if not any? turtles [ stop ]
;; exits if there are no more turtles
Note: stop can also be used to stop a forever button. See
Buttons in the
Programming Guide for details.
stop can also be used to stop a BehaviorSpace model run. If the go
commands directly call a procedure, then when that procedure calls stop,
the run ends.
stop-inspecting agent
Closes the agent monitor for the given agent (turtle or patch).
In the case that no agent monitor is open, stop-inspecting does
nothing.
stop-inspecting patch 2 4
;; the agent monitor for that patch closes
ask sheep [ stop-inspecting self ]
;; close all agent monitors for sheep
See inspect and stop-inspecting-dead-agents.
stop-inspecting-dead-agents
Closes all agent monitors for dead agents.
See inspect and stop-inspecting.
subject
Reports the turtle (or patch) that the observer is currently
watching, following, or riding. Reports nobody if there is no such turtle (or patch).
See also watch, follow,
ride.
sublist list position1 position2
substring string position1 position2
Reports just a section of the given list or string, ranging between
the first position (inclusive) and the second position (exclusive).
Note: The positions are numbered beginning with 0, not with 1.
show sublist [99 88 77 66] 1 3
=> [88 77]
show substring "apartment" 1 5
=> "part"
subtract-headings heading1 heading2
Computes the difference between the given headings, that is, the
number of degrees in the smallest angle by which heading2 could be
rotated to produce heading1. A positive answer means a clockwise
rotation, a negative answer counterclockwise. The result is always
in the range -180 to 180, but is never exactly -180.
Note that simply subtracting the two headings using the - (minus)
operator wouldn't work. Just subtracting corresponds to always
rotating clockwise from heading2 to heading1; but sometimes the
counterclockwise rotation is shorter. For example, the difference
between 5 degrees and 355 degrees is 10 degrees, not -350 degrees.
show subtract-headings 80 60
=> 20
show subtract-headings 60 80
=> -20
show subtract-headings 5 355
=> 10
show subtract-headings 355 5
=> -10
show subtract-headings 180 0
=> 180
show subtract-headings 0 180
=> 180
sum list
Reports the sum of the items in the list.
show sum [energy] of turtles
;; prints the total of the variable "energy"
;; from all the turtles
tan number
Reports the tangent of the given angle. Assumes the angle is given
in degrees.
thickness
This is a built-in link variable. It holds a number that is the
link's apparent size as a fraction of the patch size. The
default thickness is 0, which means that regardless of patch-size
the links will always appear 1 pixel wide. You can set this
variable to change a link's thickness.
tick
Advances the tick counter by one and updates all plots.
If the tick counter has not been started yet with
reset-ticks, an error results.
Normally tick goes at the end of a go procedure.
See also ticks, tick-advance, reset-ticks, clear-ticks, update-plots.
tick-advance number
Advances the tick counter by number. The input may be an
integer or a floating point number. (Some models divide ticks more
finely than by ones.) The input may not be negative.
When using tick-based view
updates, the view is normally updated every 1.0 ticks, so using
tick-advance with a number less then 1.0 may not always
trigger an update. If you want to make sure that the view is
updated, you can use the display command.
If the tick counter has not been started yet with
reset-ticks, an error results.
Does not update plots.
See also tick, ticks,
reset-ticks, clear-ticks.
ticks
Reports the current value of the tick counter. The result is always
a number and never negative.
If the tick counter has not been started yet with
reset-ticks, an error results.
Most models use the tick command to advance the tick
counter, in which case ticks will always report an
integer. If the tick-advance command is used, then
ticks may report a floating point number.
See also tick, tick-advance, reset-ticks, clear-ticks.
tie
Ties end1 and end2 of the link together. If the link
is a directed link end1 is the root turtle and
end2 is the leaf turtle. The movement of the root
turtle affects the location and heading of the leaf
turtle. If the link is undirected the tie is reciprocal so both
turtles can be considered root turtles and leaf
turtles. Movement or change in heading of either turtle affects
the location and heading of the other turtle.
When the root turtle moves, the leaf turtles moves the same
distance, in the same direction. The heading of the leaf turtle is
not affected. This works with forward, jump, and setting the xcor
or ycor of the root turtle.
When the root turtle turns right or left, the leaf turtle is
rotated around the root turtle the same amount. The heading of the
leaf turtle is also changed by the same amount.
If the link dies, the tie relation is removed.
crt 2 [ fd 3 ]
;; creates a link and ties turtle 1 to turtle 0
ask turtle 0 [ create-link-to turtle 1 [ tie ] ]
See also untie
tie-mode
This is a built-in link variable. It holds a string that is the
name of the tie mode the link is currently in. Using the tie and untie commands changes the
mode of the link. You can also set tie-mode to "free" to
create a non-rigid joint between two turtles (see the Tie section of the Programming Guide for
details). By default links are not tied.
See also: tie, untie
timer
Reports how many seconds have passed since the command reset-timer was last run (or since NetLogo
started). The potential resolution of the clock is milliseconds.
(Whether you get resolution that high in practice may vary from
system to system, depending on the capabilities of the underlying
Java Virtual Machine.)
See also reset-timer.
Note that the timer is different from the tick counter. The timer
measures elapsed real time in seconds; the tick counter measures
elapsed model time in ticks.
to procedure-name
to procedure-name [input1 ...]
Used to begin a command procedure.
to setup
clear-all
crt 500
end
to circle [radius]
crt 100 [ fd radius ]
end
to-report procedure-name
to-report procedure-name [input1 ...]
Used to begin a reporter procedure.
The body of the procedure should use report to report a
value for the procedure. See report.
to-report average [a b]
report (a + b) / 2
end
to-report absolute-value [number]
ifelse number >= 0
[ report number ]
[ report (- number) ]
end
to-report first-turtle?
report who = 0 ;; reports true or false
end
towards agent
Reports the heading from this agent to the given agent.
If wrapping is allowed by the topology and the wrapped distance
(around the edges of the world) is shorter, towards will use the
wrapped path.
Note: asking for the heading from an agent to itself, or an agent
on the same location, will cause a runtime error.
set heading towards turtle 1
;; same as "face turtle 1"
See also face.
towardsxy x y
Reports the heading from the turtle or patch towards the point
(x,y).
If wrapping is allowed by the topology and the wrapped distance
(around the edges of the world) is shorter, towardsxy will use the
wrapped path.
Note: asking for the heading to the point the agent is already
standing on will cause a runtime error.
See also facexy.
turtle number
<breed> number
Reports the turtle with the given who number, or nobody if there is no such turtle. For breeded
turtles you may also use the single breed form to refer to them.
ask turtle 5 [ set color red ]
;; turtle with who number 5 turns red
turtle-set value1
(turtle-set value1 value2 ...)
Reports an agentset containing all of the turtles anywhere in any
of the inputs. The inputs may be individual turtles, turtle
agentsets, nobody, or lists (or nested lists) containing any of the
above.
turtle-set self
(turtle-set self turtles-on neighbors)
(turtle-set turtle 0 turtle 2 turtle 9)
(turtle-set frogs mice)
See also patch-set, link-set.
turtles
Reports the agentset consisting of all turtles. This is a special agentset that can grow as turtles are added to the world, see the programming guide for more info.
show count turtles
;; prints the number of turtles
turtles-at dx dy
<breeds>-at dx dy
Reports an agentset containing the turtles on the patch (dx, dy)
from the caller. (The result may include the caller itself if the
caller is a turtle.)
create-turtles 5 [ setxy 2 3 ]
show count [turtles-at 1 1] of patch 1 2
=> 5
If the name of a breed is substituted for "turtles", then
only turtles of that breed are included.
turtles-here
<breeds>-here
Reports an agentset containing all the turtles on the caller's
patch (including the caller itself if it's a turtle).
crt 10
ask turtle 0 [ show count turtles-here ]
=> 10
If the name of a breed is substituted for "turtles", then
only turtles of that breed are included.
breed [cats cat]
breed [dogs dog]
create-cats 5
create-dogs 1
ask dogs [ show count cats-here ]
=> 5
turtles-on agent
turtles-on agentset
<breeds>-on agent
<breeds>-on agentset
Reports an agentset containing all the turtles that are on the
given patch or patches, or standing on the same patch as the given
turtle or turtles.
ask turtles [
if not any? turtles-on patch-ahead 1
[ fd 1 ]
]
ask turtles [
if not any? turtles-on neighbors [
die-of-loneliness
]
]
If the name of a breed is substituted for "turtles", then
only turtles of that breed are included.
turtles-own [var1 ...]
<breeds>-own [var1 ...]
The turtles-own keyword, like the globals, breed,
<breeds>-own, and patches-own keywords, can only be
used at the beginning of a program, before any function
definitions. It defines the variables belonging to each turtle.
If you specify a breed instead of "turtles", only turtles
of that breed have the listed variables. (More than one turtle
breed may list the same variable.)
breed [cats cat ]
breed [dogs dog]
breed [hamsters hamster]
turtles-own [eyes legs] ;; applies to all breeds
cats-own [fur kittens]
hamsters-own [fur cage]
dogs-own [hair puppies]
See also globals, patches-own, breed,
<breeds>-own.
type value
Prints value in the Command Center, not followed by a
carriage return (unlike print and show). The lack of a carriage return allows you to
print several values on the same line.
This agent is not printed before the value. unlike show.
type 3 type " " print 4
=> 3 4
See also print, show,
write, output-type, and
Output (programming guide).
undirected-link-breed [<link-breeds> <link-breed>]
This keyword, like the globals and breeds keywords, can only be
used at the beginning of the Code tab, before any procedure
definitions. It defines an undirected link breed. Links of a
particular breed are always either all directed or all undirected.
The first input defines the name of the agentset associated with
the link breed. The second input defines the name of a single
member of the breed.
Any link of the given link breed:
- is part of the agentset named by the link breed name
- has its built-in variable
breed set to that agentset
- is directed or undirected as declared by the keyword
Most often, the agentset is used in conjunction with ask to give
commands to only the links of a particular breed.
undirected-link-breed [streets street]
undirected-link-breed [highways highway]
to setup
clear-all
crt 2
ask turtle 0 [ create-street-with turtle 1 ]
ask turtle 0 [ create-highway-with turtle 1 ]
end
ask turtle 0 [ show sort my-links ]
;; prints [(street 0 1) (highway 0 1)]
See also breed, directed-link-breed
untie
Unties end2 from end1 (sets tie-mode to "none") if they were
previously tied together. If the link is an undirected link, then
it will untie end1 from end2 as well. It does
not remove the link between the two turtles.
See also tie
See the Tie section of the
Programming Guide for more details.
update-plots
For each plot, runs that plot's update commands, including the
update code for any pens in the plot.
tick has the same effect, so in models that use
the tick counter, this primitive is not normally used. Models that
use fractional ticks may need update-plots, since tick-advance does not update the plots.
See the Plotting section of
the Programming Guide for more details.
See also setup-plots.
uphill patch-variable
uphill4 patch-variable
Moves the turtle to the neighboring patch with the highest value
for patch-variable. If no neighboring patch has a higher
value than the current patch, the turtle stays put. If there are
multiple patches with the same highest value, the turtle picks one
randomly. Non-numeric values are ignored.
uphill considers the eight neighboring patches; uphill4 only
considers the four neighbors.
Equivalent to the following code (assumes variable values are
numeric):
move-to patch-here ;; go to patch center
let p max-one-of neighbors [patch-variable] ;; or neighbors4
if [patch-variable] of p > patch-variable [
face p
move-to p
]
Note that the turtle always ends up on a patch center and has a
heading that is a multiple of 45 (uphill) or 90 (uphill4).
See also downhill, downhill4.
user-directory
Opens a dialog that allows the user to choose an existing directory
on the system.
It reports a string with the absolute path or false if the user
cancels.
set-current-directory user-directory
;; Assumes the user will choose a directory
user-file
Opens a dialog that allows the user to choose an existing file on
the system.
It reports a string with the absolute file path or false if the
user cancels.
file-open user-file
;; Assumes the user will choose a file
user-new-file
Opens a dialog that allows the user to choose a location and name
of a new file to be created. It reports a string with the absolute
file path or false if the user cancels.
file-open user-new-file
;; Assumes the user will choose a file
Note that this reporter doesn't actually create the file;
normally you would create the file using file-open, as in
the example.
If the user chooses an existing file, they will be asked if they
wish to replace it or not, but the reporter itself doesn't
cause the file to be replaced. To do that you would use
file-delete.
user-input value
Reports the string that a user types into an entry field in a
dialog with title value.
value may be of any type, but is typically a string.
show user-input "What is your name?"
See the User Interaction Primitives section of the
Programming Guide for additional details.
user-message value
Opens a dialog with value displayed as the message to the user.
value may be of any type, but is typically a string.
user-message (word "There are " count turtles " turtles.")
Note that if a user closes the user-message dialog
with the "X" in the corner, the behavior will be the same as if they had clicked "OK".
See the User Interaction Primitives section of the
Programming Guide for additional details.
user-one-of value list-of-choices
Opens a dialog with value displayed as the message and
list-of-choices displayed as a popup menu for the user to
select from.
Reports the item in list-of-choices selected by the user.
value may be of any type, but is typically a string.
if "yes" = user-one-of "Set up the model?" ["yes" "no"]
[ setup ]
See the User Interaction Primitives section of the
Programming Guide for additional details.
user-yes-or-no? value
Reports true or false based on the user's response to
value.
value may be of any type, but is typically a string.
if user-yes-or-no? "Set up the model?"
[ setup ]
See the User Interaction Primitives section of the
Programming Guide for additional details.
wait number
Wait the given number of seconds. (This needn't be an integer;
you can specify fractions of seconds.) Note that you can't
expect complete precision; the agent will never wait less than the
given amount, but might wait slightly more.
repeat 10 [ fd 1 wait 0.5 ]
While the agent is waiting, no other agents can do anything.
Everything stops until the agent is done.
See also every.
watch agent
Puts a spotlight on agent. In the 3D view the observer will
also turn to face the subject.
The observer may only watch or follow a single subject.
Calling watch will undo perspective changes caused
by prior calls to follow, follow-me,
ride, and ride-me.
See also follow, subject, reset-perspective,
ride, ride-me, watch-me.
watch-me
Asks the observer to watch this agent.
The observer may only watch or follow a single subject.
Calling watch will undo perspective changes caused
by prior calls to follow, follow-me,
ride, and ride-me.
See also follow, subject, reset-perspective,
ride, ride-me, watch.
while [reporter] [ commands ]
If reporter reports false, exit the loop. Otherwise run
commands and repeat.
The reporter may have different values for different agents, so
some agents may run commands a different number of times
than other agents.
while [any? other turtles-here]
[ fd 1 ]
;; turtle moves until it finds a patch that has
;; no other turtles on it
who
This is a built-in turtle variable. It holds the turtle's
"who number" or ID number, an integer greater than or
equal to zero. You cannot set this variable; a turtle's who
number never changes.
Who numbers start at 0. A dead turtle's number will not be
reassigned to a new turtle until you use the clear-turtles or clear-all commands, at which time who numbering
starts over again at 0.
Example:
show [who] of turtles with [color = red]
;; prints a list of the who numbers of all red turtles
;; in the Command Center, in random order
crt 100
[ ifelse who < 50
[ set color red ]
[ set color blue ] ]
;; turtles 0 through 49 are red, turtles 50
;; through 99 are blue
You can use the turtle reporter to retrieve a turtle with a given
who number. See also turtle.
Note that who numbers aren't breed-specific. No two turtles can
have the same who number, even if they are different breeds:
clear-turtles
create-frogs 1
create-mice 1
ask turtles [ print who ]
;; prints (in some random order):
;; (frog 0): 0
;; (mouse 1): 1
Even though we only have one mouse, it is mouse 1 not
mouse 0, because the who number 0 was already taken by the
frog.
agentset with [reporter]
Takes two inputs: on the left, an agentset (usually
"turtles" or "patches"). On the right, a
boolean reporter. Reports a new agentset containing only those
agents that reported true -- in other words, the agents satisfying
the given condition.
show count patches with [pcolor = red]
;; prints the number of red patches
<breed>-with turtle
link-with turtle
Reports a link between turtle and the caller (directed or
undirected, incoming or outgoing). If no link exists then it reports
nobody. If more than one such link exists, reports a random one.
crt 2
ask turtle 0 [
create-link-with turtle 1
show link-with turtle 1 ;; prints link 0 1
]
See also: in-link-from, out-link-to
agentset with-max [reporter]
Takes two inputs: on the left, an agentset (usually
"turtles" or "patches"). On the right, a
reporter. Reports a new agentset containing all agents reporting
the maximum value of the given reporter.
show count patches with-max [pxcor]
;; prints the number of patches on the right edge
See also max-one-of, max-n-of.
agentset with-min [reporter]
Takes two inputs: on the left, an agentset (usually
"turtles" or "patches"). On the right, a
reporter. Reports a new agentset containing only those agents that
have the minimum value of the given reporter.
show count patches with-min [pycor]
;; prints the number of patches on the bottom edge
See also min-one-of, min-n-of.
with-local-randomness [ commands ]
The commands are run without affecting subsequent random events.
This is useful for performing extra operations (such as output)
without changing the outcome of a model.
Example:
;; Run #1:
random-seed 50 setup repeat 10 [ go ]
;; Run #2:
random-seed 50 setup
with-local-randomness [ watch one-of turtles ]
repeat 10 [ go ]
Since one-of is used inside
with-local-randomness, both runs will be identical.
Specifically how it works is, the state of the random number
generator is remembered before the commands run, then restored
afterwards. (If you want to run the commands with a fresh random
state instead of the same random state that will be restored later,
you can begin the commands with random-seed new-seed.)
The following example demonstrates that the random number generator
state is the same both before the commands run and afterwards.
random-seed 10
with-local-randomness [ print n-values 10 [random 10] ]
;; prints [8 9 8 4 2 4 5 4 7 9]
print n-values 10 [random 10]
;; prints [8 9 8 4 2 4 5 4 7 9]
without-interruption [ commands ]
This primitive exists only for backwards compatibility. We
don't recommend using it in new models.
The agent runs all the commands in the block without allowing other
agents using ask-concurrent to "interrupt". That
is, other agents are put "on hold" and do not run any
commands until the commands in the block are finished.
Note: This command is only useful in conjunction with
ask-concurrent.
See also ask-concurrent.
word value1 value2
(word value1 ...)
Concatenates the inputs together and reports the result as a
string.
show word "tur" "tle"
=> "turtle"
word "a" 6
=> "a6"
set directory "c:\\foo\\fish\\"
show word directory "bar.txt"
=> "c:\foo\fish\bar.txt"
show word [1 54 8] "fishy"
=> "[1 54 8]fishy"
show (word 3)
=> "3"
show (word "a" "b" "c" 1 23)
=> "abc123"
world-width
world-height
These reporters give the total width and height of the NetLogo
world.
The width equals max-pxcor - min-pxcor + 1 and the height equals
max-pycor - min-pycor + 1.
See also max-pxcor, max-pycor, min-pxcor, and
min-pycor
wrap-color number
wrap-color checks whether number is in the NetLogo color
range of 0 to 140 (not including 140 itself). If it is not,
wrap-color "wraps" the numeric input to the 0 to 140
range.
The wrapping is done by repeatedly adding or subtracting 140 from
the given number until it is in the 0 to 140 range. (This is the
same wrapping that is done automatically if you assign an
out-of-range number to the color turtle variable or pcolor patch
variable.)
show wrap-color 150
=> 10
show wrap-color -10
=> 130
write value
This command will output value, which can be a number,
string, list, boolean, or nobody to the Command Center, not
followed by a carriage return (unlike print
and show).
This agent is not printed before the value, unlike show. Its output also includes quotes around strings
and is prepended with a space.
write "hello world"
=> "hello world"
See also print, show,
type, output-write,
and Output (programming guide).