filter() — Advanced Examples

Returns elements from an iterable for which a function returns True

filter() protocol implementation

Implementing the protocol that filter() uses under the hood.

python

# filter() - implementing the protocol
class Custom:
    def __filter__(self):
        return "custom result"

obj = Custom()
print(filter(obj))

Understanding the dunder methods that filter() calls helps you customize behavior for your own classes.

Handling unusual inputs and edge cases.

python

# filter() edge cases
print("Edge case handling for filter()")

# Type checking
print(type(42))

Knowing these edge cases prevents subtle bugs in production.

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