12.3.10.2.4. Indexing, Slicing and Iterating

import numpy as np


# **One dimensional**
a = np.arange(10) ** 3
a[2]

8

a[2:5]

array([ 8, 27, 64], dtype=int32)

a[:6:2] = 1000

reverse array

a[::-1]

array([ 729,  512,  343,  216,  125, 1000,   27, 1000,    1, 1000],
      dtype=int32)

Multi dimensional

def f(x, y):
    return 10 * x + y


b = np.fromfunction(f, (5, 4), dtype=int)
b

array([[ 0,  1,  2,  3],
       [10, 11, 12, 13],
       [20, 21, 22, 23],
       [30, 31, 32, 33],
       [40, 41, 42, 43]])

b[2, 3]

23

b[0:5, 1]

array([ 1, 11, 21, 31, 41])

b[:, 1]

array([ 1, 11, 21, 31, 41])

b[1:3, :]

array([[10, 11, 12, 13],
       [20, 21, 22, 23]])

b[-1]

array([40, 41, 42, 43])