Question

What is pythons equivalent of Ruby’s each_slice(count)?
I want to take 2 elements from list for each iteration.
Like for [1,2,3,4,5,6] I want to handle 1,2 in first iteration then 3,4 then 5,6.
Ofcourse there is a roundabout way using index values. But is there a direct function or someway to do this directly?

Answer 1

There is a recipe for this in the itertools documentation called grouper:

from itertools import izip_longest
def grouper(n, iterable, fillvalue=None):
    "grouper(3, 'ABCDEFG', 'x') --> ABC DEF Gxx"
    args = [iter(iterable)] * n
    return izip_longest(fillvalue=fillvalue, *args)

Use like this:

>>> l = [1,2,3,4,5,6]
>>> for a,b in grouper(2, l):
>>>     print a, b

1 2
3 4
5 6