Why does modifying copy of array affect original?

Question

Hi everyone I am sorry if this is a noob question but I am using python and I have an issue where I copy an array but then when I modify the copy it affects the original. I

Answer 1

toAdd is not a duplicate. The following makes toAdd refer to the same sub-list as xyzCoord[i]:

toAdd = xyzCoord[i]

When you change elements of toAdd, the corresponding elements of xyzCoord[i] also change.

Instead of the above, write:

toAdd = xyzCoord[i][:]

This will make a (shallow) copy.