Python empty list Exception

Question

I have this function:

def foo():
    a = []
    if not a:
        print "empty"
        return None
    else:
        print "not empty"
        return a

Is there any Exception that do the same? Just to remove the if condition. Something like this:

def foo(list):
    try:
        a = list
        return a
    except:
        return None

Your first function doesn't make sense - `if not a:` will always be `True`...also, please don't use `list` as a variable name. — Tim Pietzcker, Nov 16 '14 at 12:53
Also, why do you want to return `None` instead of an empty list? An empty list already evaluates to a boolean `False`, so what's the reasoning behind your question? — Tim Pietzcker, Nov 16 '14 at 12:56
This sounds like the [XY problem](http://meta.stackexchange.com/questions/66377/what-is-the-xy-problem). What is it you actually want to do with the list? *Why* do you want to check if it's empty? — Lukas Graf, Nov 16 '14 at 12:56

Padraic Cunningham · Answer 1 · 2014-11-16T12:59:05.937

11

I would just use return l if l else None, you could try to index the list but I would not recommend it.

def foo(l):
    try:
        l[0]
        return l
    except IndexError:
        return None

edited Nov 16 '14 at 12:59

answered Nov 16 '14 at 12:53

3

It is better to not use just `except`, as it can hide unexpected errors. Use `except IndexError` instead. – stalk Nov 16 '14 at 12:54
@stalk, true, added, I would not use an except at all, it was just to show that it was possible. – Padraic Cunningham Nov 16 '14 at 12:58

1 Answers1