CODEWITHSUNDEEP
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ThomasC
ThomasC

Reputation: 891

How can I dynamically change the number of variable a netlogo agent has?

I have a model where agents or patches have an opinion of two things A and B:

patches-own[
OpinionA
OpinionB
]

And then the values for these are set randomly at the start.

How could I change this so that there could be more than two things? In fact, I'd like to have that number set by a slider. How can I dynamically change the number of variable an agent or patch has?

Upvotes: 1

Views: 504

Answers (2)

bergant
bergant

Reputation: 7232

You could use table extension:

extensions [table]

patches-own[
  opinions
]

to setup
  ask patches [
    set opinions table:make
  ]
  ; ... 
end

Set opinions with "key-value" pair where key is the opinion type and value the actual attitude. For example:

ask n-of 5 patches [
  table:put opinions "favorite-color" "blue"
  table:put opinions "food" "pizza"
]

You can set different number of opinions to another group of patches:

ask n-of 5 patches [
  table:put opinions "favorite-color" "red"
  table:put opinions "food" "chocolate"
  table:put opinions "age" 5
]

Show opinion about food (for patches with opinion about food):

ask patches with [ table:has-key? opinions "food" ] 
  [ show table:get opinions "food ]

Dynamic version

Example, how to set n opinions randomly:

 let number-of-opinions 3
 ask n-of 5 patches [
   (foreach n-values 3 [?] n-values 3 [random 10]
     [ table:put opinions ?1 ?2 ])
 ]

Here 3 opinions (named 0, 1 and 2) have been set with random numbers (from 0 to 9). To check opinion 1 use:

ask patches with [ table:has-key? opinions 1 ] 
  [ show table:get opinions 1 ]

Note that with checks if specific opinion type is set before asking for value.

See also table examples in documentation.

Upvotes: 1

nldoc
nldoc

Reputation: 1209

I don`t think it is possible to create new agent-variables on the fly, but you could instead use just one agent-variable and use a list to store multiple Opinions. You could define the length of that list by a slider and randomly set each position of the list to a specific Opinion. For example if you want the patches to have x different Opinions (defined by the slider x) which have either "a", "b" or "c" you could do that as follows:

patches-own[
  opinion
]

to setup
  ... (some setup procedure stuff)

  let opinion-options (list "a" "b" "c")

  ask patches[
    set opinion n-values x [one-of opinion-options]
  ]

Upvotes: 4

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