filter()Expert Examples

Returns elements from an iterable for which a function returns True

filter() performance and internals

Performance characteristics and CPython implementation details.

python
# filter() internals
import dis

def using_filter():
    pass

# Bytecode analysis
dis.dis(using_filter)

# Check if it's truly built-in
import builtins
print(f"\nfilter is builtin: {hasattr(builtins, 'filter')}")
print(f"Type: {type(builtins.filter)}")

Understanding the internal implementation helps optimize hot paths in performance-critical code.

Want to try these examples interactively?

Open Expert Playground