remove a list from a list

[Tim Chase]

> I have a list like
>    e = ['a', 'b', 'e']
> and another list like
>    l = ['A', 'a', 'c', 'D', 'E']
> I would like to remove from l all the elements that appear in e 
> case-insensitive. That is, the result would be
>    r = ['c', 'D']
> 
> What is a *nice* way of doing it?


Well, it's usually advantageous (for speed purposes) to make a 
set out of your lookup data.  One can then use it for a list 
comprehension something like

 >>> e = ['a', 'b', 'e']
 >>> l = ['A', 'a', 'c', 'D', 'E']
 >>> s = set(e)
 >>> [x for x in l if x.lower() not in s]
['c', 'D']

This presumes that "e" is all lowercase letters.  Otherwise, you 
can force it with

	s = set(c.lower() for c in e)

-tkc