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

Answer 1

In python 2.x

range(x) returns a list, that is created in memory with x elements.

>>> a = range(5)
>>> a
[0, 1, 2, 3, 4]

xrange(x) returns an xrange object which is a generator obj which generates the numbers on demand. they are computed during for-loop(Lazy Evaluation).

For looping, this is slightly faster than range() and more memory efficient.

>>> b = xrange(5)
>>> b
xrange(5)