Popping all items from Python list

list-comprehension, python, python-2.7

Solution

In fact, why not just

def pop_all(self):
    result, self._internal_list = self._internal_list, []
    return result

... if you are reassigning `self._internal_list` anyway, why not just return the old one instead of copying it?

Problem

I'm wondering if there is a way to "pop all" items from a list in Python? It can be done in a few lines of code, but the operation seems so simple I just assume there has to be a better way than making a copy and emptying the original. I've googled quite a bit and searched here, but to no avail. I realize that popping all items will just return a copy of the original list, but that is exactly why I want to do just that. I don't want to return the list, but rather all items contained therein, while at the same time clearing it. ``` class ListTest(): def __init__(self): self._internal_list = range(0, 10) def pop_all(self): result, self._internal_list = self._internal_list[:], [] return result # ... instead of: # return self._internal_list.pop_all() t = ListTest() print "popped: ", t.pop_all() print "popped: ", t.pop_all() ``` ... which of course returns the expected: ``` popped: [0, 1, 2, 3, 4, 5, 6, 7, 8, 9] popped: [] ```

Original source