Python List Copying Garbage Collection

Question

I have a list a and set it to [1, 2, 3, 4, 5]. Then I set b to a. My goal is to make two seperate versions of a, aka, I want b to change while a dosen't change. However, when I remove 5 from b, a becomes, [1, 2, 3, 4], exactly the same as b! My code is shown below:

a = [1, 2, 3, 4, 5]
b = a
b.remove(5)
print(b, a)

Here is my output:

[1, 2, 3, 4] [1, 2, 3, 4]

How can I achieve my goal?

By making a copy of a or better -- by taking a slice of a excluding the last element — Azat Ibrakov, May 16 '21 at 02:45

score 1 · Accepted Answer · answered May 16 '21 at 02:44

1

To make a copy of a, you can use:

b = a[:]

This question has been asked already.

answered May 16 '21 at 02:44

OrangeMonkey

26
3

score 1 · Answer 2 · edited May 17 '21 at 13:52

1

or you can take part of the list:

a = [1,2,3,4,5]
b = a[:4]
print(a,b)

edited May 17 '21 at 13:52

dimay

2,768
1
13
22

answered May 16 '21 at 17:12

Naaman

62
3

score 1 · Answer 3 · answered May 16 '21 at 17:27

1

You can use the following code without changing the original list


a = [1,2,3,4,5]
b = a.copy()

answered May 16 '21 at 17:27

MANSOOR BASHA SYED

58
3

Python List Copying Garbage Collection

3 Answers3