CODEWITHSUNDEEP
pythonsortingrank
ricoflow
ricoflow

Reputation: 125

What is the best approach to rank a dictionary of objects?

Given the following classes:

class Comparison():

    def __init__(self, value):
        self.value = value
        self.rank = 0

class Comparisons(dict):

    def __init__(self):
        super(Comparisons, self).__init__()

    def rank(self):
        # Method to examine each Comparison instance and
        # assign Comparison.rank based on Comparison.value

What is an efficient way for the rank() method to examine the objects and assign a rank? For example:

comparisons = Comparisons()

# store some Comparison instances
comparisons['one'] = Comparison(10)
comparisons['two'] = Comparison(5)
comparisons['three'] = Comparison(1)

# function to rank the comparisons
comparisons.rank()

print(comparisons['one'].rank)
print(comparisons['two'].rank)
print(comparisons['three'].rank)

Returns:

3
2
1

If the rank() method could handle ties, that would be even more beneficial.

Upvotes: 0

Views: 109

Answers (1)

Selcuk
Selcuk

Reputation: 59238

This looks like the most intuitive (naive?) way:

def rank(self):
    sorted_comparisons = sorted(self.values(), key=lambda c: c.value)
    for rank, comparison in enumerate(sorted_comparisons, 1):
        comparison.rank = rank

Upvotes: 1

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