Pythonic way with more than one max possible

[Thomas Jollans]

On 20/07/11 06:19, Steven D'Aprano wrote:
> On Wed, 20 Jul 2011 01:17 pm CM wrote:
> 
>> I have three items in a dict, like this:
>>
>> the_dict = {'a':1, 'b':2, 'c':3}
>>
>> but the vals could be anything.  I want to configure something else
>> based on the "winner" of such a dict, with these rules:
>>
>> 1. In this dict, if there is a UNIQUE max value, that's the winner.
>> 2. If there are any TIES for max value, b is the winner by default.
>>
>> The problem for me, as I see it, is I don't know any elegant ways to
>> do this in Python.  The max(dict) function doesn't distinguish between
>> unique and non-unique maxes.  I could go through and test the various
>> possibilities (to see if the max value had any matches in the other
>> values), but, knowing Python, there is probably something close to
>> "one way to do it".  Any suggestions?
> 
> # Untested.
> def get_winner(adict):
>     values = sorted(adict.values(), reverse=True)
>     if values[0] == values[1]:
>         return adict['b']
>     else:
>         return values[0]

# Untested, with keys:
def get_winner(adict):
    values = sorted(adict.items(), reverse=True,
                    key=(lambda k_v: k_v[1]))
    if values[0][1] == values[1][1]:
        return 'b'
    else:
        return values[0][0]

> 
> Assumes that adict has at least two items. May be slow if it has millions of
> items.
> 
>