List/Array

Sample

def f(value) :
    return value * 2

a = [1, 2, 3]

list(map(f, a))
list(map(lambda x: (x * 2), a))
[f(x) for x in a]
[(x * 2) for x in a]

## [2, 4, 6]

a = [1, 2, 3]
b = [4, 5, 6]

list(map(lambda x, y: (x * y), a, b))

## [4, 10, 18]

a = [[1, 2], [3, 4], [5, 6]]

list(map(lambda y: list(map(lambda x: (x * 2), y)), a))

## [[2, 4], [6, 8], [10, 12]]

import numpy as np

def f(value) :
    return value * 2

vf = np.vectorize(f)
vf(a)

## array([[2, 4], [6, 8], [10, 12]])

a = [[1, 2, 3], [3, 4, 5], [5, 6, 7]]

list(zip(*a))

## [(1, 3, 5), (2, 4, 6), (3, 5, 7)]

list(map(list, zip(*a)))

## [[1, 3, 5], [2, 4, 6], [3, 5, 7]]

import numpy as np
np.asarray(a).T

## array([[1, 3, 5], [2, 4, 6], [3, 5, 7]])

keys = ['a', 'b', 'c']
values = [1, 2, 3]

list(zip(keys, values))

## [('a', 1), ('b', 2), ('c', 3)]

dict(zip(keys, values))

## {'a': 1, 'b': 2, 'c': 3}

a = [1, 2, 3, 4, 5, 6]
b = [1, 2, 3, 1, 2, 3]

def f(value) :
    return value % 2 == 0

list(filter(f, a))
list(filter(lambda x: x % 2 == 0, a))

## [2, 4, 6]

list(filter(lambda x: x[0] == x[1], zip(a, b)))

## [(1, 1), (2, 2), (3, 3)]

a = [1, 2, 3]

for index, value in enumerate(a) :
    print(f'{index}: {value}')

## 0: 1
## 1: 2
## 2: 3