8.21. Operator Module¶

operator.add()
operator.sub()
operator.mul()
operator.truediv()
operator.floordiv()
operator.mod()
operator.pow()
operator.matmul()
operator.neg()
operator.pos()
operator.invert()

8.21.1. Operator Module - AND¶

& 1 = 1
& 0 = 0
& 1 = 0
& 0 = 0

>>> from operator import and_
>>>
>>>
>>> and_(True, True)
True
>>> and_(True, False)
False
>>> and_(False, True)
False
>>> and_(False, False)
False

8.21.2. Operator Module - OR¶

| 1 = 1
| 0 = 1
| 1 = 1
| 0 = 0

>>> from operator import or_
>>>
>>>
>>> or_(True, True)
True
>>> or_(True, False)
True
>>> or_(False, True)
True
>>> or_(False, False)
False

8.21.3. Operator Module - XOR¶

^ 1 = 0
^ 0 = 1
^ 1 = 1
^ 0 = 0

>>> from operator import xor
>>>
>>>
>>> xor(True, True)
False
>>> xor(True, False)
True
>>> xor(False, True)
True
>>> xor(False, False)
False

8.21.4. Reduce¶

>>> from functools import reduce
>>>
>>> data = [1, 2, 3, 4]

>>> def add(x, y):
...     return x + y
>>>
>>> def sub(x, y):
...     return x - y
>>>
>>> def mul(x, y):
...     return x * y
>>>
>>>
>>> reduce(add, data)
10
>>> reduce(sub, data)
-8
>>> reduce(mul, data)
24

>>> reduce(lambda x,y: x+y, data)
10
>>> reduce(lambda x,y: x-y, data)
-8
>>> reduce(lambda x,y: x*y, data)
24

>>> from operator import add, sub, mul
>>>
>>> reduce(add, data)
10
>>> reduce(sub, data)
-8
>>> reduce(mul, data)
24

8.21.5. Methodcaller¶

>>> from operator import methodcaller
>>>
>>> colors = ['red', 'green', 'blue']

>>> result = filter(lambda x: x.startswith('r'), colors)
>>> list(result)
['red']

>>> result = filter(methodcaller('startswith', 'r'), colors)
>>> list(result)
['red']

8.21.6. Reduce¶

>>> from functools import reduce
>>> from operator import add

>>> data = [
...     [1, 2, 3],
...     [4, 5, 6],
...     [7, 8, 9],
... ]

>>> result = 0
>>>
>>> for row in data:
...     for digit in row:
...         result += digit
>>>
>>> print(result)
45

>>> sum(data[0])
6
>>>
>>> sum(data[1])
15
>>>
>>> sum(data[2])
24
>>>
>>>
>>> sum(data[0]) + sum(data[1]) + sum(data[2])
45

>>> reduce(add, data[0])
6
>>>
>>> reduce(add, data[1])
15
>>>
>>> reduce(add, data[2])
24
>>>
>>>
>>> reduce(add, [
...     reduce(add, data[0]),
...     reduce(add, data[1]),
...     reduce(add, data[2]),
... ])
45

8.21.7. Map-Reduce¶

>>> from functools import reduce
>>> from itertools import starmap
>>> from operator import add, sub, mul

>>> def square(x):
...     return x ** 2
>>>
>>> def cube(x):
...     return x ** 3
>>>
>>> def apply(data, fn):
...     return map(fn, data)

>>> data = [1, 2, 3, 4]
>>> funcs = [square, cube]
>>>
>>> result = reduce(apply, funcs, data)
>>> list(result)
[1, 64, 729, 4096]
>>>
>>> result = reduce(apply, funcs, data)
>>> reduce(add, result)
4890

>>> data = [1, 2, 3, 4]
>>> funcs = [add, sub, mul]
>>>
>>> result = [reduce(fn,data) for fn in funcs]
>>> reduce(add, result)
26
>>>
>>> result = map(lambda fn: reduce(fn,data), funcs)
>>> reduce(add, result)
26

>>> data = [1, 2, 3, 4]
>>> funcs = [
...     (add, data),
...     (sub, data),
...     (mul, data),
... ]
>>>
>>> result = starmap(reduce, funcs)
>>> reduce(add, result)
26

>>> data = [1, 2, 3, 4]
>>> result = starmap(reduce, [
...     (add, data),
...     (sub, data),
...     (mul, data)])
>>>
>>> reduce(add, result)
26