CODEWITHSUNDEEP
pythonpsychopy
Steve
Steve

Reputation: 327

Accessing variables from within a function

I'm displaying some stimuli and then checking for keypresses via a keypress function, but I can't seem to be able to access the variables in that function e.g. Quit is supposed to be initiated if the user presses Q during key checks, and if the user presses 'g', running turns to '2' which is supposed to exit the overall while loop. I have tried using global variables, but I still could not get it to work, I'm also aware that global variables are considred risky.

def check_keys():
    allKeys = event.getKeys(keyList = ('g','h','escape'))
    for thisKey in allKeys:
        if thisKey == 'escape':
            dataFile.close()
            window.close()
            core.quit()
        elif thisKey == 'g':
             keyTime=core.getTime()
             thisResp = 1      
        elif thisKey == 'h':
             keyTime=core.getTime()
             thisResp = 0    

thisResp = 2
running = 1
while running == 1:

    for frame in range(frames):
        fix.draw()
        upper_target.draw()
        z= window.flip()
        check_keys()
        if thisResp == 1:
            running = 2:

print running

Any help is appreciated.

Upvotes: 1

Views: 77

Answers (1)

gr1zzly be4r
gr1zzly be4r

Reputation: 2152

Since thisResp is not defined before the check_keys() method, the method is not going to change the value of thisRep. In order to change the value of thisResp, I would either pass it as an argument to the check_keys(), or have check_keys() return either 1 or 0 and then set the value of thisResp to what's return. Your code would look like the following using the second approach:

def check_keys():
    allKeys = event.getKeys(keyList = ('g','h','escape'))
    for thisKey in allKeys:
        if thisKey == 'escape':
            dataFile.close()
            window.close()
            core.quit()
        elif thisKey == 'g':
            keyTime=core.getTime()
            return 1      
        elif thisKey == 'h':
            keyTime=core.getTime()
            return 0
       return 2

thisResp = 2
running = 1
while running == 1:

    for frame in range(frames):
        fix.draw()
        upper_target.draw()
        z= window.flip()
        thisResp = check_keys()
        if thisResp == 1:
            running = 2
            break

print running

Upvotes: 2

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