How to search list of objects for index of minimum

You can use min's key argument to search by index:

index = min(range(len(schools)), key=lambda i: schools[i].students_per_class())
print(schools[index])

A key provides the values that will be compared instead of the actual sequence. Here, my sequence is range(len(schools)), which is just the indices of all the elements. But instead of finding the minimum index, I am making it so that we find the minimum of schools[i].students_per_class() for each index i.

If you wanted to be able to compare, sort, find the min/ max on the items directly you could use the "dunder" methods. These methods allow you to overload built in functions on classes.

For instance if you had a class like this

class Item:
    def __init__(self, value):
        self.value = value

    def __lt__(self, other):
        return self.value < other.value

    def __eq__(self, other):
        return self.value == other.value

You can then create two instances and compare them directly like this,

A = Item(1)
B = Item(2)

print(A < B) # Prints True

or if you had a list of items

items = [A, B]

You can then get the minimum item by going

min_item = min(items)

or the index of it by going

min_item_index = items.index(min(items))

although it may be enough to just have a reference to the minimum item.

How to search list of objects for index of minimum

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