Insert a newline character every 64 characters using Python

Question

Using Python I need to insert a newline character into a string every 64 characters. In Perl it\'s easy:

s/(.{64})/$1\\n/

How could this be

Answer 1

itertools has a nice recipe for a function grouper that is good for this, particularly if your final slice is less than 64 chars and you don't want a slice error:

def grouper(iterable, n, fillvalue=None):
    "Collect data into fixed-length chunks or blocks"
    # grouper('ABCDEFG', 3, 'x') --> ABC DEF Gxx
    args = [iter(iterable)] * n
    return izip_longest(fillvalue=fillvalue, *args)

Use like this:

big_string = 
output = '\n'.join(''.join(chunk) for chunk in grouper(big_string, 64))