Built-in functions

The builtins module is the implicit base of every name lookup. It holds the always-available functions, constants, and exception classes. This page is the complete catalogue.

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

Functions

Object inspection and construction

Function	Behaviour
type(object) / type(name, bases, dict)	Get type, or construct a class.
isinstance(obj, type_or_tuple)	Type test.
issubclass(cls, type_or_tuple)	Subtype test.
id(obj)	Identity number.
hash(obj)	Compute hash.
repr(obj)	Canonical string.
ascii(obj)	repr with non-ASCII escaped.
dir([obj])	Attribute listing.
vars([obj])	__dict__ of obj.
callable(obj)	True if tp_call is set.
hasattr(obj, name)	True if getattr would succeed.
getattr(obj, name[, default])	Attribute lookup.
setattr(obj, name, value)	Attribute set.
delattr(obj, name)	Attribute delete.
object()	Bare object.

Numeric

Function	Behaviour
abs(x)	Absolute value (__abs__).
divmod(a, b)	(a // b, a % b).
pow(base, exp[, mod])	base ** exp or modular exponentiation.
round(number[, ndigits])	Banker's rounding.
min(iter, *, key=None, default=...) / min(*args)	Minimum.
max(iter, *, key=None, default=...) / max(*args)	Maximum.
sum(iter[, start])	Sum elements.
bool([x])	Convert to bool.
int([x[, base]])	Convert to int.
float([x])	Convert to float.
complex([real[, imag]])	Construct complex.
bin(x) / oct(x) / hex(x)	Integer representation strings.

Sequence and iteration

Function	Behaviour
len(s)	__len__.
iter(obj[, sentinel])	Get iterator.
next(it[, default])	Advance iterator.
reversed(seq)	Reverse iterator.
sorted(iter, *, key=None, reverse=False)	New sorted list.
enumerate(iter, start=0)	(index, value) pairs.
zip(*iters, strict=False)	Tuples from each iterable.
map(fn, *iters)	Apply fn lazily.
filter(fn, iter)	Keep truthy results.
range([start,] stop[, step])	Lazy arithmetic progression.
slice([start,] stop[, step])	Construct slice object.
tuple([iter])	Tuple from iterable.
list([iter])	List from iterable.
dict([mapping_or_iter], **kwargs)	Dict construction.
set([iter])	Set from iterable.
frozenset([iter])	Frozenset from iterable.
bytes([source[, encoding[, errors]]])	Bytes from iterable/str/int.
bytearray([source[, encoding[, errors]]])	Mutable bytes.
memoryview(obj)	Buffer view.
str([object[, encoding[, errors]]])	Convert to str.
any(iter)	Short-circuit truthy.
all(iter)	Short-circuit falsy.

I/O and execution

Function	Behaviour
print(*objects, sep=' ', end='\n', file=sys.stdout, flush=False)	Print.
input([prompt])	Read a line.
open(file, mode='r', buffering=-1, encoding=None, errors=None, newline=None, closefd=True, opener=None)	Open a file.
exec(source, globals=None, locals=None, *, closure=None)	Compile and run.
eval(source, globals=None, locals=None)	Evaluate expression.
compile(source, filename, mode, flags=0, dont_inherit=False, optimize=-1)	Produce a code object.
__import__(name, globals=None, locals=None, fromlist=(), level=0)	Backend of import.

Class machinery

Function	Behaviour
classmethod(fn)	Descriptor: bind to class.
staticmethod(fn)	Descriptor: bypass self.
property(fget=None, fset=None, fdel=None, doc=None)	Managed attribute.
super([type[, object_or_type]])	Cooperative method lookup.
__build_class__(func, name, *bases, **kwds)	Implementation of class statement.

Formatting

Function	Behaviour
format(value, format_spec='')	Call __format__.
repr(obj)	Canonical string.
chr(int)	Code point -> character.
ord(char)	Character -> code point.

Hashing and identity

Function	Behaviour
hash(obj)	Compute hash via __hash__.
id(obj)	Identity number.
globals()	Module-level namespace.
locals()	Active local namespace.
breakpoint(*args, **kwargs)	Call sys.breakpointhook.

Constants

Name	Value
True	The truthy singleton.
False	The falsy singleton.
None	The unit singleton.
NotImplemented	Sentinel returned by binary operators.
Ellipsis (...)	Singleton.
__debug__	True unless run under -O.
__name__	'__main__' in script context.
__doc__	Module docstring.
__package__	Containing package name.
__spec__	Module spec.
__loader__	Loader instance.
__file__	Source file path.
__builtins__	Builtins reference inside other modules.
copyright / credits / license / help / exit / quit	Interactive helpers installed by site.py.

Classes exposed via builtins

The classes corresponding to every built-in type are also available by name from builtins:

bool, bytearray, bytes, complex, dict, ellipsis, enumerate, filter,
float, frozenset, int, list, map, memoryview, object, property,
range, reversed, set, slice, staticmethod, str, super, tuple, type,
zip, classmethod

Plus the exception hierarchy (see Built-in exceptions).

Argument-clinic-style signatures

Many builtins are written with positional-only and keyword-only markers. The full signatures are documented in Python/clinic/bltinmodule.c.h. Examples:

abs($module, x, /)
print($module, /, *args, sep=' ', end='\n', file=None, flush=False)
sorted($module, iterable, /, *, key=None, reverse=False)
zip($module, /, *iterables, strict=False)
min($module, /, *args, default=<unrepresentable>, key=None)

The leading $module is the implicit module argument. / marks positional-only; * marks the start of keyword-only.

Exception classes

Every exception class listed in Built-in exceptions is available from builtins.

Gopy status

Function or constant group	State
All built-in functions listed above	Complete.
All constants	Complete.
All built-in classes	Complete.
All exception classes	Complete.
input line editing	Falls back to bare reads when stdin is not a TTY; rlwrap recommended.

Reference

• CPython 3.14: Built-in functions.
• Python/bltinmodule.c. The implementations.
• module/builtins/. gopy's port.
• Built-in types.
• Built-in exceptions.