# Force end of routine with two key presses, within time limit

**URL:** <https://discourse.psychopy.org/t/force-end-of-routine-with-two-key-presses-within-time-limit/3744>\
**Category:** Coding\
**Created:** [January 15, 2018, 3:55pm UTC](https://discourse.psychopy.org/t/force-end-of-routine-with-two-key-presses-within-time-limit/3744 "2018-01-15T15:55:52Z")\
**Posts on this page:** 6\
**Page:** 1

<div class="post-metadata">

**Author:** ![Silvia](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.psychopy.org/silvia/32/5689_2.png) [@Silvia](https://discourse.psychopy.org/u/Silvia)\
**Post date:** [January 15, 2018, 3:55pm UTC](https://discourse.psychopy.org/t/force-end-of-routine-with-two-key-presses-within-time-limit/3744/1 "2018-01-15T15:55:52Z")

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Hi everybody,  
I’m new to python so I apologize in advance if my question is trivial.

When I present the probe for my task, I want the response to be made with two key presses. I want the two key presses to force the end of the routine, but also if a time limit is reached the routine has to finish.  
In other words, I’d want the same as event.waitKeys(), but with two key presses.

I tried using core.wait() like this:

```auto
core.wait(5)
x=event.getKeys('v, b, n, m')
if len(x)>=2:
   continueRoutine=False
elif len(x)<2
   continueRoutine=True

```

But it always waits the 5 seconds, even with two key presses. I guess core.wait() is not “overridden” by the ContinueRoutine=False.

I also tried to use a while loop and a timer:

```auto
timer=core.CountdownTimer(5)
while timer.getTime()>0:
   x=event.getKeys('v, b, n, m')
   if len(x)<2:
      continueRoutine=True
   elif len(x)>=2:
      continueRoutine=False

```

But it’s not working. I guess it depends on the timing and order in which the operations are carried out, because if I try to print x I get many empty lists.

Any ideas on how to solve this issue?

Thank you!

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**Author:** ![Michael](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.psychopy.org/michael/32/16_2.png) [@Michael](https://discourse.psychopy.org/u/Michael)\
**Post date:** [January 15, 2018, 9:20pm UTC](https://discourse.psychopy.org/t/force-end-of-routine-with-two-key-presses-within-time-limit/3744/2 "2018-01-15T21:20:28Z")

</div>

> [@Please surround python code with backticks](https://discourse.psychopy.org/t/please-surround-python-code-with-backticks/1775):
>
> When you include python code on this forum please put triple “backticks” like this ``` on the line before and the line after your code. If you’ve done it correctly then your code will appear in a grey box with correct indentation like this (check the preview of your post on the right hand side before posting it) and other people will be better able to work out what might be right/wrong with your code. if myVal==True: break If you’ve already posted something that didn’t follow this rule th…

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**Author:** ![Michael](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.psychopy.org/michael/32/16_2.png) [@Michael](https://discourse.psychopy.org/u/Michael)\
**Post date:** [January 15, 2018, 9:30pm UTC](https://discourse.psychopy.org/t/force-end-of-routine-with-two-key-presses-within-time-limit/3744/3 "2018-01-15T21:30:35Z")

</div>

This is the usual case of computers frustratingly doing exactly what you tell them 😉

In the first case, you ask to wait for 5 s and only then check for any key presses which may have occurred. So naturally, this will always lead to a 5 second delay before any responses can be dealt with.

So your instinct of checking more frequently within a loop is the correct one. The issue this creates is the opposite: the checking is now so fast that it is unlikely that you will ever detect a pair of keys simultaneously. i.e. the first key will be detected, but the second key will likely not be detected until a subsequent iteration. With frequent checking like this, even if the subject pushes two keys, your code will register them in two separate single-element lists. Hence, the length of the list will hardly ever be \> 1.

So you need to add some extra logic. Set a flag (e.g. `first_key_detected`) to be `False` initially and `True` when the first key is found. Only quit the routine when **_both_** a key press is detected and `first_key_detected == True`.

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<div class="post-metadata">

**Author:** ![Silvia](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.psychopy.org/silvia/32/5689_2.png) [@Silvia](https://discourse.psychopy.org/u/Silvia)\
**Post date:** [January 16, 2018, 10:32am UTC](https://discourse.psychopy.org/t/force-end-of-routine-with-two-key-presses-within-time-limit/3744/4 "2018-01-16T10:32:34Z")

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Hi Michael,  
thank you for your kind and very clear response. I tried to implement your suggestion but I didn’t manage to make it work. My problem is that I get again an empty list for every iteration in which it checks for a key press. Also, psychopy seems to freeze for a few seconds.

```auto
timer=core.CountdownTimer(5)
first_key_detected=False
while timer.getTime()>0:
   x=event.getKeys('v, b, n, m')
   if x!=[]
        first_key_detected=True
   if len(x)<0 and first_key_detected==True:
      continueRoutine=False
   else:
       continueRoutine=True

```

By many trial and errors, I found an alternative and very simple solution:

```auto
xTimer=core.Clock()
first_key_detected=event.waitKeys(x_dur, 'v, b, n, m', timeStamped=xTimer)
print first_key_detected
second_key_detected=event.waitKeys(x_dur,'v, b, n, m', timeStamped=xTimer)
print second_key_detected
x=first_key_detected+second_key_detected
print x

```

I didn’t even try this solution earlier because I expected the first event.waitKeys to skip the routine, but this is not the case. It behaves exactly as I wanted and I get a list of two tuples (pressed key and corresponding time stamp).

Nevertheless, I think the solution you suggested might be very useful in other contexts, so I would really appreciate if you could point out what I was doing wrong when trying to implement it!

Thank you again! 🙂

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<div class="post-metadata">

**Author:** ![Michael](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.psychopy.org/michael/32/16_2.png) [@Michael](https://discourse.psychopy.org/u/Michael)\
**Post date:** [January 16, 2018, 10:13pm UTC](https://discourse.psychopy.org/t/force-end-of-routine-with-two-key-presses-within-time-limit/3744/5 "2018-01-16T22:13:00Z")

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Just to check: I’ve been assuming that this experiment is entirely your own code.

If using Code components in Builder, we can’t use `waitKeys()` or loops, as Builder is structured around a screen refresh drawing loop that we can’t interrupt with code that will take longer than one screen refresh.

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<div class="post-metadata">

**Author:** ![Silvia](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.psychopy.org/silvia/32/5689_2.png) [@Silvia](https://discourse.psychopy.org/u/Silvia)\
**Post date:** [January 17, 2018, 9:37am UTC](https://discourse.psychopy.org/t/force-end-of-routine-with-two-key-presses-within-time-limit/3744/6 "2018-01-17T09:37:44Z")

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Yes, it is entirely code!