Alter elements of a list

Question

I have a list of booleans where occasionally I reset them all to false. After first writing the reset as:

for b in bool_list:
    b = False

I found it doesn't work. I spent a moment scratching my head, then remembered that of course it won't work since I'm only changing a reference to the bool, not its value. So I rewrote as:

for i in xrange(len(bool_list)):
    bool_list[i] = False

and everything works fine. But I found myself asking, "Is that really the most pythonic way to alter all elements of a list?" Are there other ways that manage to be either more efficient or clearer?

Answer 1

If you only have one reference to the list, the following may be easier:

bool_list = [False] * len(bool_list)

This creates a new list populated with False elements.

See my answer to Python dictionary clear for a similar example.