每次试验的 psychopy 重置变量

Question

我制作了自己的评分量表，这是一个从 0 到 28:18 的时间轴。它根据人们在每次试验中按下 't' 或 'b' 键的速度而移动。屏幕上出现的内容如下所示：

我希望每次试用时顶部的时间都重置为 14:09。每次试验后有 0.5 秒的试验间隔，在此期间屏幕上会显示“+”。我遇到的问题是，如果您在 ITI 期间按 't' 或 'b'，下一次试验将不会在 14:09 开始。相反，它将按 't' 或 'b' 按下移动时间线的方向移动。这是我尝试更正的当前代码：

prevPos = 0
trialNum=0
b_list=[]
t_list=[]
key=[]

# loop through pictures
for eachPic in catPictures:
    b_list=[]
    t_list=[]
    timer = core.CountdownTimer(TrialDuration)
    while timer.getTime() > 0:
        for key in event.getKeys():
            if key in ['escape']:
                core.quit() # quit if they press escape
            if key in ['b']:
                # add keypress to list for each keypress. then move cursor proportionally to length of this list
                b_list.append(key)
                prevPos+=len(b_list)
            if key in ['t']:
                t_list.append(key)
                prevPos-=len(t_list)

    # set upper and lower limits to where cursor can go (which will later be halved to restrict range of cursor on the screen)
        if prevPos <= -849:
            prevPos = -849
        elif prevPos >=849:
            prevPos = 849
        # make absolute position so pos_absolute becomes a range from 0 to 300 (based on 28:18 min movie)
        pos_absolute = prevPos + 849
        # need to have range of 1698 (# of seconds in 28:18)
        # need to have range of 1698 (# of seconds in 28:18)
        # current range is 0 to 849 (which is 50% of 1698)
        seconds =  pos_absolute

        Image2 = visual.ImageStim(window)
        #curbImage2.setSize = ((0.5,0.5), units = 'norm')
        # make a little higher than the absolute middle
        Image2.setPos([0,100])
        # use each image (i in curbImages)
        Image2.setImage(catPictures[trialNum])

        # define cursor that moves along timeline
        cursorImage = visual.ImageStim(window)
        cursorImage.setImage(directoryStim+'cursor.png')
        # make cursor move by however big prevPos is
        cursorImage.setPos([int(prevPos)*.5,int(400)])
        # make the line
        timeline = visual.SimpleImageStim(win=window, image=directoryStim+'line.png', units='pix', pos=[0, 400])
    event.clearEvents() # get rid of other, unprocessed events

        # print min and max values next to timeline
        min = visual.TextStim(window, '0:00', color='Black', pos=[-500, 400])
        max = visual.TextStim(window, '28:18', color='Black', pos=[500, 400])
        # print constantly updating time value
        timeText = visual.TextStim(window,'%d:%02d' % (seconds/60, seconds % 60),color='Black',wrapWidth=1080,font='Verdana', pos=[0,465], height=50)

        ## now put everything on the screen
        Image2.draw(window)
        min.draw(window)
        max.draw(window)
        timeText.draw(window)
        timeline.draw(window)
        cursorImage.draw(window)
    ## flip so it actually appears
        window.flip()

    ITI = visual.TextStim(window, '+', pos=[0,0], height=50, color='Black')
    ITI.draw(window)
    window.flip()
    core.wait(.5,.5)
    trialNum+=1
    prevPos = 0
    b_list =[]
    t_list=[]
    key=[]

如何在每次试验开始时将我的时间线重置为 14:09（又名 prevPos = 0），即使人们按 't' 或 'b'在试验结束时或在试验间隔期间？

Answer 1

在代码的最后一行，试试这个：

event.clearEvents()

在 ITI 期间按下的键将进入缓冲区，因此将在您下次调用 event.getKeys() 时收集。通过调用 clearEvents()，您可以刷新该缓冲区。

Answer 2

在内部 for 循环下缩进内容。
将您的 event.clearEvents() 移动到 while 循环之前或者在 core.wait 之后。这就是您开始收听新内容的地方按键。在等待期间按下将返回在下一个循环中调用 event.getKeys() while 循环。这就是它立即移动光标的原因。没有在你拥有它的地方拥有 event.clearEvents() 的真正原因因为您只监听 while 循环中的事件。这就是为什么我建议您移动它而不是插入一个新的。
启动心理刺激非常耗费资源有时可能需要几百毫秒。没有创建几个新的 ImageStims 和 TextStims 的原因每次试验。
pos_absolute 和 seconds 是多余的。你只能用 seconds.
风格的东西：而不是 stim.setPos(x) 你现在可以对所有其他属性做 stim.pos = x 等等。这是从现在开始设置刺激属性的首选方式（更简洁的代码并允许对属性进行更多操作）。

这是经过上述更改后的清理代码：

# Stimuli
Image2 = visual.ImageStim(window)
cursorImage = visual.ImageStim(window)
min = visual.TextStim(window, '0:00', color='Black', pos=[-500, 400])
max = visual.TextStim(window, '28:18', color='Black', pos=[500, 400])
timeText = visual.TextStim(window,color='Black',wrapWidth=1080,font='Verdana', pos=[0,465], height=50)
ITI = visual.TextStim(window, '+', pos=[0,0], height=50, color='Black')
timeline = visual.SimpleImageStim(win=window, image=directoryStim+'line.png', units='pix', pos=[0, 400])
timer = core.CountdownTimer(TrialDuration)

# loop through pictures
trialNum=0
for eachPic in catPictures:
    prevPos = 0
    key=[]
    b_list=[]
    t_list=[]
    timer.reset()
    event.clearEvents() # get rid of other, unprocessed events
    while timer.getTime() > 0:
        for key in event.getKeys():
            if key in ['escape']:
                core.quit() # quit if they press escape
            if key in ['b']:
                # add keypress to list for each keypress. then move cursor proportionally to length of this list
                b_list.append(key)
                prevPos+=len(b_list)
            if key in ['t']:
                t_list.append(key)
                prevPos-=len(t_list)

        # set upper and lower limits to where cursor can go (which will later be halved to restrict range of cursor on the screen)
        if prevPos <= -849:
            prevPos = -849
        elif prevPos >=849:
            prevPos = 849
        # make absolute position so pos_absolute becomes a range from 0 to 300 (based on 28:18 min movie)
        # need to have range of 1698 (# of seconds in 28:18)
        # need to have range of 1698 (# of seconds in 28:18)
        # current range is 0 to 849 (which is 50% of 1698)
        seconds =  prevPos + 849

        #curbImage2.size = ((0.5,0.5), units = 'norm')
        # make a little higher than the absolute middle
        Image2.pos = [0,100]
        # use each image (i in curbImages)
        Image2.image = catPictures[trialNum]

        # define cursor that moves along timeline
        cursorImage.image = directoryStim+'cursor.png'
        # make cursor move by however big prevPos is
        cursorImage.pos = [int(prevPos)*.5,int(400)]
        timeText.text = '%d:%02d' % (seconds/60, seconds % 60))

        ## now put everything on the screen
        Image2.draw(window)
        min.draw(window)
        max.draw(window)
        timeText.draw(window)
        timeline.draw(window)
        cursorImage.draw(window)
        ## flip so it actually appears
        window.flip()

    ITI.draw(window)
    window.flip()
    core.wait(.5,.5)
    trialNum+=1

请注意，我还删除了 b_list、key 等几个看似不必要的重置

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