Asking Turtle to evaluate color of different breed of Turtle

Question

I'm building interactions for a prey-predator model.

I have a prey that changes color based on the state that it is currently in. The state that I'm working on is "hiding", in which the prey is yellow. I have a predator working to evaluate if it can chase a prey, I'm attempting to do this by evaluating the color of the prey but it doesn't seem to be working.

to chase
  let target min-one-of prey [distance myself]
  output-print target
  ifelse target != yellow 
  [

     output-print "chase"
  ]
  [
    output-print "ignore"
  ]
end

When I run the model the predator constantly prints "chase" - regardless of whether the prey is "hiding" or not.

Here is the hiding function.

to hiding
  set color yellow
  set energy (energy - 1)
  if (count predators = 0)
[
  output-print "safe"
]
end

Any help would be appreciated.

score 2 · Accepted Answer · answered Nov 14 '15 at 19:09

to access the color (or any other variable of an agent) you surround the variable name in brackets and use "of" thus

[color] of target

in context of your code it would look like this

 to chase
 let target nearest-of prey
 output-print target
 ifelse [color] of target != yellow 
 [

  output-print "chase"
 ]
 [
 output-print "ignore"
 ]

end

it takes some time to get used to as it is quite different than the object.variable form used by "C" style languages.

Asking Turtle to evaluate color of different breed of Turtle

1 Answers1