Specifying trial/loop number within a code component

Builder
1

I’m building an experiment in which participants (verbally) name pictures presented onscreen, and their responses are detected by a nearby microphone. I have a code component which saves each response as a separate audio file:

vpvk = vk.OnsetVoiceKey(
sec=10
file_out = english_word + ‘.wav’)

**note the pictures are pulled from an excel file, and ‘english_word’ is just the label given to each picture.

My problem is that I have multiple repetitions of each picture within my loop, meaning that when a picture is repeated, the previous audio file for that picture is overridden. Is there a way to specify the repetition/trial number for the output file, so that a separate file is generated for each iteration of each picture? Any help would be appreciated!

2

Check the API here for the TrialHandler class, which represents the loop in Builder:
http://www.psychopy.org/api/data.html

They have attributes for the current trial number. So do something like this:

file_out = english_word + str(name_of_your_loop.thisN) + '.wav')
3

Hi Michael,

Thanks for the help! Unfortunately I have multiple loops (with different names) which all use the same routine (and hence, the same lines of code). Is it possible to do what you suggest in a way that generalises to all of my loops?

Regards
Lyam

4

Hi Lyam,

Look into this post and where it links to:

5

Hi Michael,

Thanks for this. I’ve altered my code to include:

if practiceTrials.finished:
thisLoop = trials
else:
thisLoop = practiceTrials

However when I try to run it, Psychopy complains that “practiceTrials is not defined”. Any suggestions on how to correct this?

6

And the error message suggests, you need to make sure that the routine is within a loop called practiceTrials.

Your previous messages suggest that you’re wanting a way to refer to a generic loop name instead of a specific one, though. It’s hard to give advice without you telling us exactly what you are doing, and ideally giving a screenshot of your flow panel.

7

This sort of question suggests you would benefit from the workshop!

http://www.psychopy.org/resources/workshops.html#bep

8

Hi all,

Thanks again for the input. Fortunately I found a workaround to my problem. Technically I didn’t really need to specify thisN, I just needed a way to distinguish between each individual trial. I ended up adding str(core.getTime()) to my output file path, so that now each trial generates a unique filename. It’s not very elegant but it works :slight_smile: