python 2 simple for loop high memory usage [duplicate]

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
– Tim Peters, Commented Aug 20, 2017 at 17:56

Danil Speransky · Accepted Answer · 2017-08-20 18:03:29Z

3

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

edited Aug 20, 2017 at 18:03

answered Aug 20, 2017 at 17:56

Danil Speransky

30.5k6 gold badges70 silver badges78 bronze badges

Sign up to request clarification or add additional context in comments.

Collectives™ on Stack Overflow

python 2 simple for loop high memory usage [duplicate]

1 Answer 1

Comments

Linked

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Linked

Related