Nested lists or conditional logic?

[Peter Otten]

mike beck wrote:

> this is not all complex, but as a noob i'm having a hard time getting
> my head around it.
> 
> i have a list of items. i need to print the items in batches of x,
> with a summary line after each complete or partial batch, and a total
> line at the end of the job.

[...]

> i've done the following, which works, but it seems like there must be
> a better/simpler/faster way to do this with nested loops. ideas?

Your code looks OK to me (apart from the duplicate colon). Here's a "no
maths" variant that uses nested loops:

from itertools import islice

ITEMSINBATCH = 3;
ARBITRARYNUM = 11;

sample = ["item #%d" % i for i in range(ARBITRARYNUM)]
it = iter(sample)

while True:
    more = False
    for item in islice(it, ITEMSINBATCH):
        more = True
        print item
    if not more: break
    print "summary"

I'm generally fond of the itertools module; this time I didn't find a way to
get rid of the ugly more flag, though. Implementing your own iterator with
a hasMore() method seems overkill.

Peter