CODEWITHSUNDEEP
positioningnetlogo
chermen
chermen

Reputation: 620

netlogo: how to position turtles in certain location

I want to position my turtles in a certain squared location. Why does this code below not work? Netlogo accepts it, but does not compile, saying "can't set turtle variable XCOR to non-number false" It should be pretty simple, but I somewhat can't get around it.

crt 50
[
  set size 2

  set xcor xcor >= 81 and xcor <= 90 ;set initial location 
  set ycor ycor >= 81 and ycor <= 90 ;of turtles
  set start-patch patch-here
  pen-down
]

Upvotes: 1

Views: 4940

Answers (1)

Nicolas Payette
Nicolas Payette

Reputation: 14972

The error message pretty much says it all: set xcor should be followed by an expression that evaluates to a number. In your code, however, set xcor is followed by a boolean expression (i.e., something that evaluates to true or false): xcor >= 81 and xcor <= 90.

In other words, xcor >= 81 and xcor <= 90 does not mean "give me a number between 81 and 90", it is a question meaning "is xcor between 81 and 90?" and NetLogo does not know how to set xcor to the answer to this question.

If you want NetLogo to give you a number that is in a certain range, you generally need to use the random function. In your case, you could simply do:

set xcor 81 + random 10
set ycor 81 + random 10

Note that random will only give you integers. If you wanted your turtles to be at non-integer coordinates, you could use random-float instead.

Upvotes: 4

Related Questions