Maintaining values of lists after copying

Question

list1=["a","b","c","d"]
list2 = list1

list1.remove("a")

print(list1,list2) ----> ['b', 'c', 'd'] ['b', 'c', 'd']

In the list mentioned above, I want to retain old values which I had copied from list1 to list2.

But after I modify list1, list2 is still pointing to list1 contents.

How can I prevent this from happening and have list2 containing the values ["a","b","c","d"]

`list2 = list1` This does NOT make a copy of list1. It creates a new name list2 that refers to the SAME object. — John Gordon, Feb 05 '22 at 16:50

score 0 · Accepted Answer · answered Feb 05 '22 at 16:54

use copy() like this

list1=["a","b","c","d"]
list2 = list1.copy()
list1.remove("a")
print(list1,list2)   # ['b', 'c', 'd'] ['a', 'b', 'c', 'd']

or list slicing

list1=["a","b","c","d"]
list2 = list1[:]
list1.remove("a")
print(list1,list2)   # ['b', 'c', 'd'] ['a', 'b', 'c', 'd']

or list()

list1=["a","b","c","d"]
list2 = list(list1)
list1.remove("a")
print(list1,list2)   # ['b', 'c', 'd'] ['a', 'b', 'c', 'd']

1 Answers1