List insert at index that is well out of range - behaves like append

Question

I had a list

 a = [1, 2, 3]

when I did

a.insert(100, 100)

[1, 2, 3, 100]

as list was originally of siz

Answer 1

Instead of contrasting insert to item assignment, it's more analogous to slice assignment, since both change the size of the list.

>>> a = [1, 2, 3]
>>> a[100:100] = [100]
>>> a
[1, 2, 3, 100]

Slices also don't raise IndexError, and so is consistent with:

a.insert(100, 100)