How to prevent a loop from pressing backspace in a typed response

Coding
1

I managed to get every thing right following this tutorial

I run it, it works fine until I pressed backspace twice. it gets me into a loop of having the last letter pressed appeared (which removed by the first click on backspace). on a third click on a backspace the word “backspace” appeared and on trying to end this by pressing Enter it doesn’t work.

This is the code I enter in Each Frame:

if(“backspace” in key_resp_task4.keys):
key_resp_task4.keys.remove(“backspace”)

if(len(key_resp_task4.keys) > 0):
    key_resp_task4.keys.pop()

elif(“return” in key_resp_task4.keys):
key_resp_task4.keys.remove(“return”)

if(len(key_resp_task4.keys) > 3):
   screen_text1 = ''.join(key_resp_task4.keys)
   thisExp.addData("recall_resp4", screen_text1)

   continueRoutine = False

screen_text1 = ‘’.join(key_resp_task4.keys)

Any one encounter such problem. My guessing are it is something related to the code pop() and that a code to end the loop is needed!

2

I also get this error when I run it online

  • TypeError: Cannot use ‘in’ operator to search for ‘backspace’ in undefined
3

Hello,

if you read the comments you’ll notice that your are not the only person for which this approach does not work. See this for an alternative approach.

Best wishes Jens

1 Like
4

Thanks Jens

I’ve followed the way of coding in the suggested link. As I can see in this method, there is no need to add a keyboard as in the case of the old method. However, when I run it in the builder and tried to type the response, the typed text cannot be seen. This is the case in the builder.

I tried also to run it online and encountered this error code message:

  • TypeError: Cannot read property ‘clearEvents’ of undefined

Any idea what’s the reason and how to solve it?

5

Hello,

When you run the experiment online, you need to add some lines JavaScript, see here.

Create a JavaScript only code-element at the beginning of your experiment and add, at least, the following lines (you find an explanation following the link above). See the attached experiment below for a similar code-element, codeJS, in the first routine, startExp, of the experiment

thisExp=psychoJS.experiment;
win=psychoJS.window;
event=psychoJS.eventManager;
shuffle = util.shuffle;
Array.prototype.append = [].push;

Well, if you don’t see your type input when running locally, your code is not yet correct :wink:

Take a look at the attached experiment. You can ignore most of the experiment. It is change-blindness experiment in German. The relevant routine is called “Bericht” ChangBlindExp3.psyexp (47.5 KB). codeAntwort is the code-element used to register the typed answer and antwort the text-element to display the response. Be aware that some non-English keys might not work.

Cheers Jens

1 Like
6

Thank you so much, it worked well now. Do you know how to limit pressing “return” unless after typing at least 3 letters?

7

Hello,

you need to check for the length of inputText. So something around this line should do the job in python:

if actualKeys[i] == 'return' and len(inputText > 2):

Now, the routine only ends if the length of inputText is larger than 2 and return is pressed.

Cheers Jens

1 Like
8

Thank you so much Jens.