'delete' in python removing from every existing list?

Asked Sep 23 '17 at 08:21

Active Sep 23 '17 at 08:21

Viewed 25 times

Sorry for the titlegore, but I can't think of a better way to describe it.

Just to show what I mean, this:

a = ['1', '2', '3']
b = a
b.remove(b[0])
print(b)
print(a)

outputs this:

['2', '3']
['2', '3']

when I expected this:

['2', '3']
['1', '2', '3']

Why is this? How would I go about deleting something from the second list while keeping the first the same?

asked Sep 23 '17 at 08:21

Kurt Ferrier

`a` and `b` are the *same* list. – Daniel Roseman Sep 23 '17 at 08:23
use b = a[:] instead of b = a – Reza Sep 23 '17 at 08:27
With b = a, you don't actually have two lists. The assignment just copies the reference to the list, not the actual list, so both "a" and "b" refer to the same list after the assignment. Use the syntax as @Reza suggested to get the desired output – Ramineni Ravi Teja Sep 23 '17 at 08:43
Thank you. I used b = list(a) – Kurt Ferrier Sep 23 '17 at 11:11

0 Answers0