OS (e.g. Win10): Mac OS10
PsychoPy version (e.g. 1.84.x): 2020.1.2
**Standard Standalone? Yes
What are you trying to achieve?:
I have a practice trial part of my experiment. In builder, I set this up as a loop that references a .csv file with trial information for 48 possible trials, in 48 rows. However, I want to randomly select only 5 of those 48.
What did you try to make it work?:
I tried the advice from the main psychopy site under “flow”, which says to set Selected Rows to random(desired number of trials)*total rows in csv.
Images of things I’ve tried are below.
What specifically went wrong when you tried that?:
When I use the advice from the main psychopy site, I get this error: " for n in selection:
TypeError: ‘NoneType’ object is not iterable"
When I use the advice from the forum posts (the added code snippet), I do not get an error, but the experiment runs through all the rows in my practrials.csv file.
Thanks for any guidance! After trying all the things I could find, I’m really not sure why this isn’t working for me.