High Order Function in Python

#python #code #datastructure

  • High order function are functions that accept other functions
  • Example: sorted and map 
>>> def reverse(word):
...     return word[::-1]
>>> reverse('testing')
'gnitset'
>>> sorted(fruits, key=reverse)
['banana', 'apple', 'fig', 'raspberry', 'strawberry', 'cherry']
  • Decorators are functions that accept other functions to be decorated - Decorators in python
    • They usually return a different inner function using the argument function

Map, filter, and reduce 

>>> list(map(factorial, range(6)))  (1)
[1, 1, 2, 6, 24, 120]
>>> [factorial(n) for n in range(6)]  (2)
[1, 1, 2, 6, 24, 120]
>>> list(map(factorial, filter(lambda n: n % 2, range(6))))  (3)
[1, 6, 120]
>>> [factorial(n) for n in range(6) if n % 2]  (4)
[1, 6, 120]

Anonymous Functions

  • lambda functions
    • They don’t have names, only bodies
  • They are rare, but can be used with high order functions
  • If they are big enough transform them into def function 

>>> fruits = ['strawberry', 'fig', 'apple', 'cherry', 'raspberry', 'banana']
>>> sorted(fruits, key=lambda word: word[::-1])
['banana', 'apple', 'fig', 'raspberry', 'strawberry', 'cherry']

sources

  • Fluent Python - Luciano Ramalho - 2023 - Second Edition - Web Edition
Eu com algumas figuras que representa análise de dados/ciência
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