Question

I need to find what element of apple has the minimum size.

Tnx for all answers. But there is one problem: I use Python 2.4.2 (I can’t change it) and function min haven’t key arg. Yes, I need key of apple

apple = {1:{'size':12,'color':'red'},2:{'size':10,'color':'green'}}

Answer 1

Python has a very nice parameter for the min function that allows using an arbitrary function to be minified instead of just using comparison on the elements:

result = min(apple.values(), key=lambda x:x['size'])

The key parameter replaced in most cases the older idiom of decorate-process-undecorate that could have been applied here:

result = min((x['size'], x) for x in apple.values())[1]

If instead you want to know the number (key) of the apple (it’s not clear in the question) then:

result = min(apple.keys(), key=lambda x:apples[x]['size'])

or (old style)

result = min((apples[x]['size'], x) for x in apple.keys())[1]