How do I do what strtok() does in C, in Python?

Generally, I try to avoid regular expressions, but if you want to split on a bunch of different things, they work. Try this:

import re
result = [int(x) for x in filter(None, re.split('[,\n,\t]', A))]

How about this:

A = '1, 2,,3,4  '
B = [int(x) for x in A.split(',') if x.strip()]

x.strip() trims whitespace from the string, which will make it empty if the string is all whitespace. An empty string is "false" in a boolean context, so it's filtered by the if part of the list comprehension.