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https://docs.python.org/3/reference/datamodel.html

• __init__: constructor

• __del__: destructor ?? (use with care)

• __delete__:

• __new__: this is called before __init__

• __get__: read attribute value

• __set__: write attribute value

• __getattr__:

• __getattribute__:

• __setattr__:

• __delattr__:

• __getitem__: used when reading from x[i]

• __setitem__: used when writing to x[i]

• __delitem__: used when deleting

• __missing__:

• __repr__: representation of object as a string

• __str__: human readable representation of object as string

• __lt__, - __gt__, - __le__, - __ge__, - __eq__, - __ne__: comparison

• __format__: used by format() function (and f-strings)

• __hash__: used by hash()

• __bytes__: used by bytes()

• __bool__: used by bool()

• __iter__: used by iter()

• iterator.__next__():

• __reversed__:

• __contains__:

• __dir__: used by dir()

• __call__:

• __len__:

• __length_hint__:

• __enter__: enter context manager

• __exit__: leave context manager

• __objclass__:

• __slots__:

• __init_subclass__:

• __set_name__:

• __prepare__:

• __mro_entries__:

• __classcell__: CPython specific

• __class__:

• __instancecheck__:

• __subclasscheck__:

• __class_getitem__:

• __match_args__:

• __complex__:

• __int__:

• __float__:

• __index__:

• __round__:

• __trunc__:

• __floor__:

• __ceil__:

• __buffer__:

• __release_buffer__:

• __await__:

• __aiter__:

• __anext__:

Arithmetic and related

Function	Function (rev)	Notation
__add__	__radd__	+
__sub__	__rsub__	-
__mul__	__rmul__	*
__matmul__	__rmatmul__	@
__truediv__	__rtruediv__	/
__floordiv__	__rfloordiv__	//
__mod__	__rmod__	%
__divmod__	__rdivmod__	divmod()
__pow__	__rpow__	**
__lshift__	__rlshift__	<<
__rshift__	__rrshift__	>>
__and__	__rand__	&
__xor__	__rxor__	^
__or__	__ror__	│

Functions with the r prefix are the same except that the order of arguments is reversed.

Note: Ternary pow() will not try calling rpow().

—

Function	Notation
__iadd__	+=
__isub__	-=
__imul__	*=
__imatmul__	@=
__itruediv__	/=
__ifloordiv__	//=
__imod__	%=
__ipow__	**=
__ilshift__	<<=
__irshift__	>>=
__iand__	&=
__ixor__	^=
__ior__	│=

(divmod isn't there in this list.)

—

Function	Notation
__neg__	-
__pos__	+
__invert__	~

__slot__

• Classes with slots does not have __dict__ (but their instances might??).
  • Saves space.
  • Faster attribute access
• Remark: dataclass has a slots option

See:

• https://stackoverflow.com/questions/472000/usage-of-slots
• https://wiki.python.org/moin/UsingSlots