Well, Google doesn't recommend it either (http://google-styleguide.googlecode.com/svn/trunk/pyguide.html?showone=List_Comprehensions#List_Comprehensions http://

Well, Google doesn't recommend it either (http://google-styleguide.googlecode.com/svn/trunk/pyguide.html?showone=List_Comprehensions#List_Comprehensions http://google-styleguide.googlecode.com/svn/trunk/pyguide.ht...), but I guess they are all bloody noobs or whatever. I mean, single level comprehension is good. Nested list comprehension is OK only in most trivial cases. In my opinion, if I see how a person uses list comprehension, I can tell, what kind of person this is. There are people who, for example, do this def all_is_okey_dorey(lst): return all([some_predicate_fn(x) for x in lst]) instead of this def all_is_okey_dorey(lst): for x in lst: if not some_predicate_fn(x): return False return True and can live with themselves somehow. Or there are people, who refuse to acknowledge the existence of anything besides Python 3.x and when forced to write in 2.x use list comprehension instead of iterator comprehension. Thing is, the validity of using nested list comprehension depends not on the amount of for loops you have, but on the thing you want to do with the item. If it's just selection, then it might be ok. If you want to apply some kind of function to it, then it's most probably the case of trying to be too clever.