Multiplying slider.markerPos

Online experiments
1

Hi all,
I have one question related to the slider. I want to create a slider with tickmarks going from 0 to 10 (endpoints have labels). Clicking on the slider does not end the routine, because I want the testers to have room to tweak their ratings. I have a TextStim that shows the current value, by using a code component and adding text.text=slider.markerPos in the Each Frame box. However, I want this text to show integers ranging from 0 to 100. It seems like the easiest way to get the 0-100 scores while still keeping the 0-10 tickmarks is to make ticks range from 0 to 10, set the granularity to 0.1, and then multiply slider.markerPos by 10 for the TextStim. Is that possible? When I try, I get the error:

text.text = slider.markerPos*10
TypeError: unsupported operand type(s) for *: ā€˜NoneTypeā€™ and ā€˜intā€™

I know this can be done with rating scales, but this is for an online study, so it has to be the slider.
Any help would be appreciated!

2

What happens if you try just presenting the raw slider.markerPos ?

I think the problem is that slider.markerPos is undefined until it gets clicked so you should make sure that your line of code is only executed when **slider.getRating()!= None
** (change null to undefined in JS)

This leads me to suspect that you should be using slider.getRating. e.g.

if slider.getRating() != None:
     text.setText(str(slider.getRating()*10)

Does that work locally? If so, it should translate to JS with the null=undefined as noted.

Best wishes,

Wakefield

3

Yes, that works! Thank you so much! I still get a .0 decimal (e.g., 12.0, 55.0, 73.0), but perhaps itā€™s unavoidable.

A quick follow-up question: I have a loop where a stimulus routine is first presented, and then a rating routine with the slider and the TextStim showing the sliderā€™s value. The TextStim seems to remember the slider rating from the previous trial. Thus, you see a value on the screen before clicking on the slider in all trials except the first. Is it possible to reset the text in the next trial?

Thanks again!

4

You should be able to round() to remove the decimal and .setText(ā€˜ā€™) to remove the text.

5

The .setText("") works, but not the round() function. Where would you place that function? This does not work (no error, but still shows the .0 decimal):

if slider.getRating() != None:
    text.setText(str(round(slider.getRating()*10)))
6

Did you add round=Math.round; or

round = function(num, n=0) {    
    return +(Math.round(num + ("e+" + n))  + ("e-" + n));
}

to code_JS?

7

My code type is the ā€œAuto->JSā€, but I thought that the function was defined, because my Py code is automatically translated to (in the JS code):

if ((slider.getRating() !== null)) {
    text.setText(Math.round((slider.getRating() * 10)).toString());
}

If I copy and paste your function into the JS code, I still have the .0 decimal (no error message).

8

Please could you have a look at my crib sheet to see what I mean by code_JS

9

OK, so I have added a code component in my first routine, moved it to the top, switched from ā€œAuto->JSā€ to JS, and copied and paste this into the ā€œBegin Experimentā€ box:

round = function(num, n=0) {    
    return +(Math.round(num + ("e+" + n))  + ("e-" + n));
}

But I still get the .0 decimal. By the way, does it matter that every time I open code_JS, it has switched back to ā€œAuto->JSā€?

10

Iā€™m sure Iā€™ve come across this before but I canā€™t remember how I solved it. How about str(int(slider.getRating() * 10)) ?

11

Yes, that worked! thank you!

1 Like
12

BTW, it doesnā€™t matter that it defaults back to Auto so long as you donā€™t click on the Python window.