[solved] Randomize variable lists

Comments

• eduard

  October 2014 edited 12:41PM

  Hi Andrea,

  Unfortunately, like it was said in the thread you cited, you need to do some scripting in order to design your experiment in the way you want it. However, it is not very hard, so no need to worry. Here you can find the basic structure of how you can solve your problem. I will explain it briefly:

  1. In the first inline_script, called "define_Amount", you have to create the list of the 45 options of how much money each subject can get per trial. You want it to be randomized, so you have to shuffle the list.

  import random
  
  exp.amount_list = [1,2,3,4....45] # or whatever it is in your case
  random.shuffle(exp.amount_list)
  

  2. After having created that list, you can enter the trial loop. Here, you have to add your other variable (i.e. probability) with each of the 45 levels included (just like that ). If you do it this way, the sequence, which is repeated in the loop takes exactly one of the probabilities as "P" variable for a trial. As you might have noticed, at this point the sequencedoesn't "know" yet what the other variable (amount) is, because it isn't included in the variable assistant. So, this is what we have to do in step 3.

  3. In the inline_script "set_amount_as_variable", you have to set the value of the 2nd variable.

  exp.set('amount', exp.amount_list.pop())
  

  That's it. Now the sequence has one value for the probability and one for the amount. Each value is used exactly once and also in a random order for each participant. From this point, you can use them, in the way you described (" If [prob] equals [amount], ...").

  Two small remarks:

  1) Obviously, it doesn't matter which of your variables you define in the variable assistant and which you define yourself. It is totally up to you.

  2) When you define one variable yourself in the very first inline_script, you shouldn't forget to put "exp." in front of the variable name, because if you don't, you won't be able to access it outside this inline_script. By adding "exp." you make it part of your experiment and hence, accessible at any point of it.

  Do you understand now better?

  Eduard

  
• Andrea_sct

  October 2014 edited October 2014

  Thanks for your help,
  when I try to begin an exp the software says:
  "Variable 'amount' is not set in item 'rest_of_trial'.
  You are trying to use a variable that does not exist. Make sure that you have spelled and capitalized the variable name correctly. You may wish to use the variable inspector (Control + I) to find the intended variable."

  When I open variable inspector and I search for amount's variable I find:
  "amount" in variable column
  [Set to 'exp.amount_list.pop('] in the second column.

  I put the script you post under the "run" label, is it correct?
  Will it work if I change:

  • numeric with character;

  • labels "amount" with "D";

  in this way:

  first inline_script:

  import random

  exp.D_list = ["1","2","3","4","5"] # or whatever it is in your case
  random.shuffle(exp.D_list)

  and the second inline_script:

  exp.set('D', exp.D_list.pop())
• eduard

  October 2014 edited 12:41PM

  Hi Andrea,

  when I try to begin an exp the software says: "Variable 'amount' is not set in item 'rest_of_trial'.

  You defined your variable as part of the experiment, that is, if you want to access the variable, you have to tell Opensesame that it has to look for it in the experiment. The way this works is either by using brackets, [amount], or like this: exp.amount.

  Will it work if I change:

  numeric with character;

  labels "amount" with "D";

  Sure, the way you label your variables is pretty much your own decision.

  Eduard

  
• Andrea_sct

  October 2014 edited October 2014

  Hi eduard,
  with the first inline I create the list:

  import random

  exp.amount_list = [1,2,3,4....45] # or whatever it is in your case

  random.shuffle(exp.amount_list);

  in the second inline I include the variable in the variable assistant:

  exp.set('amount', exp.amount_list.pop())

  and so when in the slider's question I write " If you have [prob] of win [amount]..." it should work or I forget to do something?
• eduard

  October 2014 edited 12:41PM

  Exactly, that sums it up very well. I don't see a reason why it shouldn't work now, but why don't you just try it out?

  Eduard

  
• Andrea_sct

  October 2014 edited 12:41PM

  I have tried it but the variable amount hasn't been identified in the slider
• eduard

  October 2014 edited 12:41PM

  Does it work if you use "exp.amount" instead of [amount] ?

  
• Andrea_sct

  October 2014 edited 12:41PM

  Nothing the software doesn't recall the list and put in the questions exactly the words "exp.amount"

  I try to move the inline script from run label to prepare label and the first windows works but when I click to accept answer it says:

  Error while executing inline script phase: prepare
  item: set_Amount_as_Variable
  line: 2
  exception message: 'int' object has no attribute 'pop'
  exception type: AttributeError

  Traceback (also in debug window):
  File "dist\libopensesame\inline_script.py", line 133, in prepare
  File "", line 2, in
  AttributeError: 'int' object has no attribute 'pop'
• eduard

  October 2014 edited 12:41PM

  The error tells you that the element you're popping from is not a list, but an integer.
  So something went wrong there. Did you make sure, that you create a list in define_amount? Maybe you can post the code you used.

  Btw. you're right, you have to set the amount for the trial in the prepare phase of the inline_script.

  
• Andrea_sct

  October 2014 edited 12:41PM

  I thought that amount_list was only the variable name and so I change it to "M" now I have changed it to "M_list" and the experiment work.
  Thanks for your help.
• eduard

  October 2014 edited 12:41PM

  Nice!

  Good luck with it.

  Eduard