[TriLUG] OT-ish: Python array slicing question

[Nathan Yinger via TriLUG]

There is a difference: a[:] creates a copy.

a = [1, 2, 3, 4, 5]
b = a
c = a[:]
a[0] = 7
print(b) # [7, 2, 3, 4, 5]
print(c) # [1, 2, 3, 4, 5]

~Nathan

On Mon, Dec 12, 2022 at 11:18 AM Brian via TriLUG <trilug at trilug.org> wrote:

> Hi Gang,
>
> I figure there's probably someone in the group that can answer a
> question for me.
>
> I'm maintaining some Python code written by people no longer with the
> company.  I'm also a Python newbie myself, so now and then I come across
> something that doesn't make sense and eludes my Google-fu.
>
> Given an array:
> a = [1, 2, 3, 4, 5]
>
> Is there any difference whatsoever in these two conventions:
>
> b = a[:]
> b = a
>
> A simple experiment in an interactive session doesn't seem to show any
> difference, and my understanding of array slicing says there shouldn't
> be any difference, so why would anyone write the former instead of the
> latter?
>
> Thanks,
> -Brian
> --
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