#### Howdy, Stranger!

It looks like you're new here. If you want to get involved, click one of these buttons!

Supported by

# reverse list issue

edited July 16

Hello

I have a corsi memory task all ready running with an inline.

In the task after 4 correct responses for a sequence of n trials, the experiment moves to a sequence of n+1.

If there were less then 4 out of 7 correct answers, the experiment ends.

Now I want to turn it into a working memory task so the correct order is the reverse order.

I am trying to change:

```stiseq = sequence of stimlui
respseq = sequence of responses made by the participant
if stiseq==rspseq:
var.set(u'acc', u'1')
else:
var.set(u'acc', u'0')
```

to this:

```if stiseq==rspseq.reverse():
var.set(u'acc', u'1')
else:
var.set(u'acc', u'0')
```

I am getting the right values of stiseq and respseq,

but for some reson, acc always equals 0.

Any thought as to why this can happen? what have I done wrong?

Thank you!

• Hi @labovich ,

The `list.reverse()` function doesn't return the `list` in reverse order. Rather, it changes the list itself (inplace) such that the elements are reversed. But the return value of `list.reverse()` is always `None` .

The normal (but pretty unintuitive) way to return a reversed `list` is by slicing with steps of -1, like so: `l[::-1]` . In your case, this might work:

```if stiseq == rspseq[::-1]:
var.set(u'acc', u'1')
else:
var.set(u'acc', u'0')
```

Cheer!

Sebastiaan

• Genius! Thank you so much!!