- range
- xrange
range vs xrange in Python
examples/lists/xrange.py
from __future__ import print_function import sys r = range(1000) x = xrange(1000) for v in r: # 0..999 pass for v in x: # 0..999 pass print(sys.getsizeof(r)) # 8072 print(sys.getsizeof(x)) # 40
In Python 2 range creates a list of values range(from, to, step) and xrnage creates and iterator. In Python 3 range creates the iterator and if really necesary then list(range()) can create the list.