Source: Python Morsels

Description

Return all maximum values in an iterable.

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>>> multimax([1, 4, 2, 4, 3])
[4, 4]

Notes

Solution involved using using a lambda function as a keyword argument.

My solution

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def multimax(iter, key=lambda x: x):
    iter, max = list(iter), []
    if not len(iter):
        return max
    max.append(iter[0])
    for item in iter[1:]:
        kitem, kmax = key(item), key(max[0])
        if kitem > kmax:
            max = [item]
        elif kitem == kmax:
            max.append(item)
    return max

Provided solution

This solution does not invoke the key function on the current maximum value during each iteration, as mine does unnecessarily.

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def multimax(iterable, key=lambda x: x):
    max_key = None
    maximums = []
    for item in iterable:
        k = key(item)
        if k == max_key:
            maximums.append(item)
        elif not maximums or k > max_key:
            maximums = [item]
            max_key = k
    return maximums