How do I deep copy a list

Question

How to make a copy of a list ? I have code somewhat as follows :

l = ['1','2','3']
l.pop()

for (x in somerange):
    a = []
    a = l
    a.append("something")

But I don't want the contents of a to reflect in l. How do I make a copy of l and assign it to a.

Python already has a builtin priority queue class: http://docs.python.org/2/library/queue.html#Queue.PriorityQueue — Blender, Sep 19 '13 at 15:29
What does the title of your question have to do with the body? — thegrinner, Sep 19 '13 at 15:30
@Marcin: Don't edit "duplicate" into the title; that's put there by the system *after* it's closed as duplicate. — Wooble, Sep 19 '13 at 15:48

score 2 · Answer 1 · answered Sep 19 '13 at 15:47

You can make a shallow copy of a list (which doesn't copy any contained lists, just references them) by doing this:

a = l[:]

or

import copy
a = copy.copy(l)

The copy module also has a deepcopy function which duplicates any contained mutable objects:

import copy
a = copy.deepcopy(l)

Hope that helps!

1 Answers1