else in list comp

Andrew Bennetts andrew-pythonlist at puzzling.org
Wed Jan 29 05:26:51 CET 2003


On Tue, Jan 28, 2003 at 08:05:25PM -0800, Cliff Wells wrote:
> Maybe this has come up before, but I haven't heard a discussion of list
> comps in a while so here's something I thought might be interesting:
> 
> I was looking for a fast, clean way of converting a single value in a
> list to a different value (specifically None to '').  It occurred to me
> to use a list comp and this seemed the most straightforward solution:
> 
> Given the list:
> 
> l = ['mary', 'had', 'a', 'little', None]
> 
> it should get mapped to ['mary', 'had', 'a', 'little', '']

This doesn't solve the general problem, but...

    >>> l = ['mary', 'had', 'a', 'little', None]
    >>> [x or '' for x in l]
    ['mary', 'had', 'a', 'little', '']

-Andrew.






More information about the Python-list mailing list