On 07/14/2013 11:16 AM, Chris Angelico wrote:
> On Mon, Jul 15, 2013 at 3:10 AM, Joseph L. Casale
> <jcas...@activenetwerx.com> wrote:
>> I have a dict of lists. I need to create a list of 2 tuples, where each
>> tuple is a key from
>> the dict with one of the keys list items.
>>
>> my_dict = {
>> 'key_a': ['val_a', 'val_b'],
>> 'key_b': ['val_c'],
>> 'key_c': []
>> }
>> [(k, x) for k, v in my_dict.items() for x in v]
>>
>> This works, but I need to test for an empty v like the last key, and create
>> one tuple ('key_c', None).
>> Anyone know the trick to reorganize this to accept the test for an empty v
>> and add the else?
>
> Yeah, it's remarkably easy too! Try this:
>
> [(k, x) for k, v in my_dict.items() for x in v or [None]]
>
> An empty list counts as false, so the 'or' will then take the second
> option, and iterate over the one-item list with None in it.
Or more simply:
[(k, v or None) for k, v in my_dict.items()]
This assumes that all the values in my_dict are lists, and not
other false values like 0, which would also be replaced by None.
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