builtins

The builtins module holds the implicit namespace consulted last during name resolution. Built-in functions, constants, exceptions, and types live here. The builtins module is the canonical place to look up len, print, Exception, and so on without typing builtins. explicitly.

Source-of-record: Python/bltinmodule.c, built-in functions.

Index

For full per-function documentation see Reference -> Built-ins.

Constants

True, False, None, NotImplemented, Ellipsis, __debug__, __name__, __doc__, __package__, __loader__, __spec__, __build_class__, __import__.

Object inspection

type, isinstance, issubclass, id, hash, len, repr, ascii, dir, vars, callable, hasattr, getattr, setattr, delattr.

Numeric

abs, divmod, pow, round, bin, hex, oct, int, float, complex, bool, min, max, sum.

Sequence and iteration

iter, next, aiter, anext, enumerate, zip, range, slice, reversed, sorted, map, filter, any, all.

Constructors

bytes, bytearray, memoryview, str, list, tuple, dict, set, frozenset, object, type, super, property, staticmethod, classmethod.

I/O and execution

print, input, open, format, chr, ord, compile, exec, eval, breakpoint, help, copyright, credits, license, quit, exit.

Exceptions

The full BaseException hierarchy lives here too; see Reference -> Errors.

Customising builtins

Modifying builtins is observable everywhere. Assigning builtins.print = fn redirects print for every module that hasn't shadowed the name locally. Test runners and REPLs rely on this.

__import__

__import__(name, globals=None, locals=None, fromlist=(), level=0)

The low-level hook the import statement compiles into. Replaceable by assigning to builtins.__import__.

__build_class__

The hook that class X(...) compiles into; see Reference -> Statements (compound).

Gopy status

Area	State
All builtins listed above	Complete.
__import__ and __build_class__ hooks	Complete.
Replacement and shadowing semantics	Complete.

Reference

• CPython 3.14: builtins.
• Python/bltinmodule.c. C side.
• module/builtins/. gopy port.