operator — Standard operators as functions
The operator module exports a set of functions implemented in C
corresponding to the intrinsic operators of Python. For example,
operator.add(x, y) is equivalent to the expression x+y. The function
names are those used for special class methods; variants without leading and
trailing __ are also provided for convenience.
The functions fall into categories that perform object comparisons, logical
operations, mathematical operations, sequence operations, and abstract type
tests.
The object comparison functions are useful for all objects, and are named after
the rich comparison operators they support:

operator.lt(a, b)

operator.le(a, b)

operator.eq(a, b)

operator.ne(a, b)

operator.ge(a, b)

operator.gt(a, b)

operator.__lt__(a, b)

operator.__le__(a, b)

operator.__eq__(a, b)

operator.__ne__(a, b)

operator.__ge__(a, b)

operator.__gt__(a, b)
 Perform “rich comparisons” between a and b. Specifically, lt(a, b) is
equivalent to a < b, le(a, b) is equivalent to a <= b, eq(a,
b) is equivalent to a == b, ne(a, b) is equivalent to a != b,
gt(a, b) is equivalent to a > b and ge(a, b) is equivalent to a
>= b. Note that these functions can return any value, which may
or may not be interpretable as a Boolean value. See
Comparisons for more information about rich comparisons.
The logical operations are also generally applicable to all objects, and support
truth tests, identity tests, and boolean operations:

operator.not_(obj)

operator.__not__(obj)
 Return the outcome of not obj. (Note that there is no
__not__() method for object instances; only the interpreter core defines
this operation. The result is affected by the __bool__() and
__len__() methods.)

operator.truth(obj)
 Return True if obj is true, and False otherwise. This is
equivalent to using the bool constructor.

operator.is_(a, b)
 Return a is b. Tests object identity.

operator.is_not(a, b)
 Return a is not b. Tests object identity.
The mathematical and bitwise operations are the most numerous:

operator.abs(obj)

operator.__abs__(obj)
 Return the absolute value of obj.

operator.add(a, b)

operator.__add__(a, b)
 Return a + b, for a and b numbers.

operator.and_(a, b)

operator.__and__(a, b)
 Return the bitwise and of a and b.

operator.floordiv(a, b)

operator.__floordiv__(a, b)
 Return a // b.

operator.inv(obj)

operator.invert(obj)

operator.__inv__(obj)

operator.__invert__(obj)
 Return the bitwise inverse of the number obj. This is equivalent to ~obj.

operator.lshift(a, b)

operator.__lshift__(a, b)
 Return a shifted left by b.

operator.mod(a, b)

operator.__mod__(a, b)
 Return a % b.

operator.mul(a, b)

operator.__mul__(a, b)
 Return a * b, for a and b numbers.

operator.neg(obj)

operator.__neg__(obj)
 Return obj negated.

operator.or_(a, b)

operator.__or__(a, b)
 Return the bitwise or of a and b.

operator.pos(obj)

operator.__pos__(obj)
 Return obj positive.

operator.pow(a, b)

operator.__pow__(a, b)
 Return a ** b, for a and b numbers.

operator.rshift(a, b)

operator.__rshift__(a, b)
 Return a shifted right by b.

operator.sub(a, b)

operator.__sub__(a, b)
 Return a  b.

operator.truediv(a, b)

operator.__truediv__(a, b)
 Return a / b where 2/3 is .66 rather than 0. This is also known as
“true” division.

operator.xor(a, b)

operator.__xor__(a, b)
 Return the bitwise exclusive or of a and b.

operator.index(a)

operator.__index__(a)
 Return a converted to an integer. Equivalent to a.__index__().
Operations which work with sequences include:

operator.concat(a, b)

operator.__concat__(a, b)
 Return a + b for a and b sequences.

operator.contains(a, b)

operator.__contains__(a, b)
 Return the outcome of the test b in a. Note the reversed operands.

operator.countOf(a, b)
 Return the number of occurrences of b in a.

operator.delitem(a, b)

operator.__delitem__(a, b)
 Remove the value of a at index b.

operator.getitem(a, b)

operator.__getitem__(a, b)
 Return the value of a at index b.

operator.indexOf(a, b)
 Return the index of the first of occurrence of b in a.

operator.setitem(a, b, c)

operator.__setitem__(a, b, c)
 Set the value of a at index b to c.
Many operations have an “inplace” version. The following functions provide a
more primitive access to inplace operators than the usual syntax does; for
example, the statement x += y is equivalent to
x = operator.iadd(x, y). Another way to put it is to say that
z = operator.iadd(x, y) is equivalent to the compound statement
z = x; z += y.

operator.iadd(a, b)

operator.__iadd__(a, b)
 a = iadd(a, b) is equivalent to a += b.

operator.iand(a, b)

operator.__iand__(a, b)
 a = iand(a, b) is equivalent to a &= b.

operator.iconcat(a, b)

operator.__iconcat__(a, b)
 a = iconcat(a, b) is equivalent to a += b for a and b sequences.

operator.ifloordiv(a, b)

operator.__ifloordiv__(a, b)
 a = ifloordiv(a, b) is equivalent to a //= b.

operator.ilshift(a, b)

operator.__ilshift__(a, b)
 a = ilshift(a, b) is equivalent to a <<= b.

operator.imod(a, b)

operator.__imod__(a, b)
 a = imod(a, b) is equivalent to a %= b.

operator.imul(a, b)

operator.__imul__(a, b)
 a = imul(a, b) is equivalent to a *= b.

operator.ior(a, b)

operator.__ior__(a, b)
 a = ior(a, b) is equivalent to a = b.

operator.ipow(a, b)

operator.__ipow__(a, b)
 a = ipow(a, b) is equivalent to a **= b.

operator.irshift(a, b)

operator.__irshift__(a, b)
 a = irshift(a, b) is equivalent to a >>= b.

operator.isub(a, b)

operator.__isub__(a, b)
 a = isub(a, b) is equivalent to a = b.

operator.itruediv(a, b)

operator.__itruediv__(a, b)
 a = itruediv(a, b) is equivalent to a /= b.

operator.ixor(a, b)

operator.__ixor__(a, b)
 a = ixor(a, b) is equivalent to a ^= b.
Example: Build a dictionary that maps the ordinals from 0 to 255 to
their character equivalents.
>>> d = {}
>>> keys = range(256)
>>> vals = map(chr, keys)
>>> map(operator.setitem, [d]*len(keys), keys, vals) # doctest: +SKIP
The operator module also defines tools for generalized attribute and item
lookups. These are useful for making fast field extractors as arguments for
map(), sorted(), itertools.groupby(), or other functions that
expect a function argument.

operator.attrgetter(attr[, args...])
Return a callable object that fetches attr from its operand. If more than one
attribute is requested, returns a tuple of attributes. After,
f = attrgetter('name'), the call f(b) returns b.name. After,
f = attrgetter('name', 'date'), the call f(b) returns (b.name,
b.date).
The attribute names can also contain dots; after f = attrgetter('date.month'),
the call f(b) returns b.date.month.

operator.itemgetter(item[, args...])
Return a callable object that fetches item from its operand using the
operand’s __getitem__() method. If multiple items are specified,
returns a tuple of lookup values. Equivalent to:
def itemgetter(*items):
if len(items) == 1:
item = items[0]
def g(obj):
return obj[item]
else:
def g(obj):
return tuple(obj[item] for item in items)
return g
The items can be any type accepted by the operand’s __getitem__()
method. Dictionaries accept any hashable value. Lists, tuples, and
strings accept an index or a slice:
>>> itemgetter(1)('ABCDEFG')
'B'
>>> itemgetter(1,3,5)('ABCDEFG')
('B', 'D', 'F')
>>> itemgetter(slice(2,None))('ABCDEFG')
'CDEFG'
Example of using itemgetter() to retrieve specific fields from a
tuple record:
>>> inventory = [('apple', 3), ('banana', 2), ('pear', 5), ('orange', 1)]
>>> getcount = itemgetter(1)
>>> map(getcount, inventory)
[3, 2, 5, 1]
>>> sorted(inventory, key=getcount)
[('orange', 1), ('banana', 2), ('apple', 3), ('pear', 5)]

operator.methodcaller(name[, args...])
 Return a callable object that calls the method name on its operand. If
additional arguments and/or keyword arguments are given, they will be given
to the method as well. After f = methodcaller('name'), the call f(b)
returns b.name(). After f = methodcaller('name', 'foo', bar=1), the
call f(b) returns b.name('foo', bar=1).
Mapping Operators to Functions
This table shows how abstract operations correspond to operator symbols in the
Python syntax and the functions in the operator module.
Operation 
Syntax 
Function 
Addition 
a + b 
add(a, b) 
Concatenation 
seq1 + seq2 
concat(seq1, seq2) 
Containment Test 
obj in seq 
contains(seq, obj) 
Division 
a / b 
truediv(a, b) 
Division 
a // b 
floordiv(a, b) 
Bitwise And 
a & b 
and_(a, b) 
Bitwise Exclusive Or 
a ^ b 
xor(a, b) 
Bitwise Inversion 
~ a 
invert(a) 
Bitwise Or 
a  b 
or_(a, b) 
Exponentiation 
a ** b 
pow(a, b) 
Identity 
a is b 
is_(a, b) 
Identity 
a is not b 
is_not(a, b) 
Indexed Assignment 
obj[k] = v 
setitem(obj, k, v) 
Indexed Deletion 
del obj[k] 
delitem(obj, k) 
Indexing 
obj[k] 
getitem(obj, k) 
Left Shift 
a << b 
lshift(a, b) 
Modulo 
a % b 
mod(a, b) 
Multiplication 
a * b 
mul(a, b) 
Negation (Arithmetic) 
 a 
neg(a) 
Negation (Logical) 
not a 
not_(a) 
Right Shift 
a >> b 
rshift(a, b) 
String Formatting 
s % obj 
mod(s, obj) 
Subtraction 
a  b 
sub(a, b) 
Truth Test 
obj 
truth(obj) 
Ordering 
a < b 
lt(a, b) 
Ordering 
a <= b 
le(a, b) 
Equality 
a == b 
eq(a, b) 
Difference 
a != b 
ne(a, b) 
Ordering 
a >= b 
ge(a, b) 
Ordering 
a > b 
gt(a, b) 