a8bt-high-order-functions.md

High Order Functions

#python #functional #programming

• A function that receive another function or returns a function: Example: map, reduce, filter
• map + filter = [[ndtq-listcomp]] and [[0651-genexp]] using if
• reduce = sum

>>> fact = factorial # Function is assign to a variable, functioning like object
>>> fact
<function factorial at 0x...>
>>> fact(5)
120
>>> map(factorial, range(11))
<map object at 0x...>
>>> list(map(factorial, range(11))) # receives factorial
[1, 1, 2, 6, 24, 120, 720, 5040, 40320, 362880, 3628800]
>>> fruits = ['strawberry', 'fig', 'apple', 'cherry', 'raspberry', 'banana']
>>> sorted(fruits, key=len) # receives the len function
['fig', 'apple', 'cherry', 'banana', 'raspberry', 'strawberry']

• [[ey8t-lambda-function]]#
• [[4fmy-packages-for-functional-programming-in-python]]#

Partial

• Receives one callable and arguments with predetermined values

>>> from operator import mul
>>> from functools import partial
>>> triple = partial(mul, 3)
>>> triple(7)
21
>>> list(map(triple, range(1, 10)))
[3, 6, 9, 12, 15, 18, 21, 24, 27]

References

• Ramalho, 2022, p234-236
• Ramalho, 2022, p247-249