python 2 simple for loop high memory usage

Question

Testing with Python 2.7 and 3.5

for i in range(0, 1000000000):
    pass

When I'm running this code with python3 everything is fine (less than 3MB memory usage)

But by python2 memory usage is 32GB (my server has only 32GB of ram)

How to fix this for Python 2.7?

In Python 3, `range()` creates an iterator, but in Python 2 `range()` creates a list. In Python 2, use `xrange()` instead to create an iterator. — Tim Peters, Aug 20 '17 at 17:56

Danil Speransky · Accepted Answer · 2017-08-20T18:03:29.407

range in Python 2.7 and range in Python 3 are different functions. In Python 3 it returns an iterator which provides values one by one. In Python 2.7 it returns an array for which some memory has to be allocated. It can be solved by using xrange function in Python version 2.7.

Python 2.7.12
>>> range(10)
[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
>>> xrange(10)
xrange(10)
>>> iterator = iter(xrange(10))
>>> iterator.next()
0
>>> iterator.next()
1
>>> iterator.next()
2

python 2 simple for loop high memory usage

1 Answers1