Iteration over list slices

Question

I want an algorithm to iterate over list slices. Slices size is set outside the function and can differ.

In my mind it is something like:

for list_of_x         


        

Answer 1

For a near-one liner (after itertools import) in the vein of Nadia's answer dealing with non-chunk divisible sizes without padding:

>>> import itertools as itt
>>> chunksize = 5
>>> myseq = range(18)
>>> cnt = itt.count()
>>> print [ tuple(grp) for k,grp in itt.groupby(myseq, key=lambda x: cnt.next()//chunksize%2)]
[(0, 1, 2, 3, 4), (5, 6, 7, 8, 9), (10, 11, 12, 13, 14), (15, 16, 17)]

If you want, you can get rid of the itertools.count() requirement using enumerate(), with a rather uglier:

[ [e[1] for e in grp] for k,grp in itt.groupby(enumerate(myseq), key=lambda x: x[0]//chunksize%2) ]

(In this example the enumerate() would be superfluous, but not all sequences are neat ranges like this, obviously)

Nowhere near as neat as some other answers, but useful in a pinch, especially if already importing itertools.