how to correctly modify the iterator of a loop in python from within the loop

Question

what I basically need is to check every element of a list and if some criteria fit I want to remove it from the list.

So for example let\'s say that

list         


        

Answer 1

This is exactly what itertools.ifilter is designed for.

from itertools import ifilter

ifilter(lambda x: x not in ['b', 'c'], ['a', 'b', 'c', 'd', 'e'])

will give you back a generator for your list. If you actually need a list, you can create it using one of the standard techniques for converting a generator to a list:

list(ifilter(lambda x: x not in ['b', 'c'], ['a', 'b', 'c', 'd', 'e']))

or

[x for x in ifilter(lambda x: x not in ['b', 'c'], ['a', 'b', 'c', 'd', 'e'])]