Given an iterable of dictionaries of the form

l = (
  { 'id' : 1, 'data': 'some random data'},
  { 'id' : 2, 'data': 'other random data'},
  { 'id' : 4, 'data': 'more random data'},
)

we can find a particular item in the list by key with this lispish looking one-liner:

(lambda a: list(a)[0])(x for x in l if x['id']==2)

Obviously we could also just use this one:

[x for x in l if x['id']==2][0]

but that would destroy the joy of using an unnecessary lambda :D.

Even more beautiful is what I found on StackExchange (http://stackoverflow.com/a/9542768/1945909):

next(x for x in l if x['id']==2)

Now imagine the beautiful oneliner we could get if we knew the list was sorted by ‘id’ :).