sum()Expert Examples

Returns the total of all items in an iterable

sum() performance and internals

Performance characteristics and CPython implementation details.

python
# sum() internals
import dis

def using_sum():
    pass

# Bytecode analysis
dis.dis(using_sum)

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

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

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