loops - What is the difference between range and xrange functions in Python 2.X?

Question

Apparently xrange is faster but I have no idea why it's faster (and no proof besides the anecdotal so far that it is faster) or what besides that is different about

for i in range(0, 20):
for i in xrange(0, 20):

Answer 1

In Python 2.x:

• range creates a list, so if you do range(1, 10000000) it creates a list in memory with 9999999 elements.

• xrange is a sequence object that evaluates lazily.

In Python 3:

• range does the equivalent of Python 2's xrange. To get the list, you have to explicitly use list(range(...)).
• xrange no longer exists.