Using eval in the middle of a python statement

Question

I want to use eval in the middle of the following python statement:

["a", "b"] + eval('[1,2].append(3)')

but because it does not return any value (it works in an "in place" manner), I cannot actually use it there and instead I receive an error of TypeError: can only concatenate list (not "NoneType") to list . Is there any way that I can fix this issue by getting return value out of eval in Python?

It's not that eval doesn't return anything here. It's that list.append() doesn't return anything. — Axe319
– Axe319, Commented Oct 13, 2021 at 16:23

Barmar · Accepted Answer · 2021-10-13 16:23:23Z

3

You can use list concatenation instead of calling append(). It returns the new list.

["a", "b"] + eval('[1,2] + [3]')

answered Oct 13, 2021 at 16:23

Barmar

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