ordering a list of dictionaries by date

Question

I have the following list:

l = [{datetime.date(2011, 4, 30): "Carrot"}, 
     {datetime.date(2009, 4, 12): "Banana"},
     {datetime.date(2012, 1, 1): "Corn"}]

I want a new list with the dictionaries ordered by date (earliest first):

l = [{datetime.date(2009, 4, 12): "Banana"},
     {datetime.date(2011, 4, 30): "Carrot"},
     {datetime.date(2012, 1, 1): "Corn"}]

I expect the answer involves sorted and key but I'm struggling to isolate the key of each dictionary to use as the comparator. In other questions which have posed a similar problem, the dictionaries take the form:

{'date':datetime.date(2009, 4, 12): "Banana"} 

The addition of the date string seems to make the task easier but i'd like to avoid it if possible

cheers.

Answer 1

Use the key of your inner dictionary as sort key. You can do this by passing a key getter function to sorted which pulls out the date key from your dictionary.

sorted(l, key=lambda v: v.keys()[0])