Handle Large number in Python

Question

We have number "17179869184" which need to traverse. But we got memory error when we traverse into list. is there anyway we can handle similar kind of range number

for i in range(17179869184):
    print i

for i in xrange(17179869184):
    print i



Traceback (most recent call last):
  File "<pyshell#2>", line 1, in <module>
    for i in xrange(17179869184):
OverflowError: Python int too large to convert to C long

Answer 1

You can use itertools.count with iter:

>>> from itertools import count
>>> c = count(0)
>>> for i in iter(c.next, 17179869184):
        #do something with i

Note that if you only want to loop that number of times, i.e you're not using i inside the loop then it will be better to use itertools.repeat:

>>> from itertools import repeat
>>> for _ in repeat(None, 17179869184):
...     # do something here

Answer 2

Use a while loop:

i=0
while i < 17179869184:
    # do stuff
    i += 1

If this is being done multiple times, create a Python implementation of range() using generators.

def py_range(num):
    i = 0
    while i < num:
        yield i
        i+=1

Well, py_range() not the same as range() as it has start and other arguments. But you can search online for a complete implementation (should be there).