NumPy Array Creation

NumPy Array Creation. In this lesson, I will show how to create various NumPy array. Such as an array of zeros, array of ones, array of numbers. I used Jupyter Notebook for running the codes.

Code:

import numpy as np

Code:

a = np.array([20,30,40])
a

Output:

array([20, 30, 40])

Code:

a.dtype

Output:

dtype('int64')

Code:

b = np.array([10.2, 30.5, 50.1])
b

Output:

array([10.2, 30.5, 50.1])

Code:

b.dtype

Output:

dtype('float64')

Code:

b = np.array([(10.5,20,30), (40,50,60)])
b

Output:

array([[10.5, 20. , 30. ],
       [40. , 50. , 60. ]])

Code:

c = np.array( [ [10,20], [30,40] ], dtype=complex )
c

Output:

array([[10.+0.j, 20.+0.j],
       [30.+0.j, 40.+0.j]])

Code:

np.zeros( (4,5) )

Output:

array([[0., 0., 0., 0., 0.],
       [0., 0., 0., 0., 0.],
       [0., 0., 0., 0., 0.],
       [0., 0., 0., 0., 0.]])

Code:

np.ones((2, 4, 5), dtype=np.int16)

Output:

array([[[1, 1, 1, 1, 1],
        [1, 1, 1, 1, 1],
        [1, 1, 1, 1, 1],
        [1, 1, 1, 1, 1]],

       [[1, 1, 1, 1, 1],
        [1, 1, 1, 1, 1],
        [1, 1, 1, 1, 1],
        [1, 1, 1, 1, 1]]], dtype=int16)

Code:

np.empty((2, 3))

Output:

array([[10.5, 20. , 30. ],
       [40. , 50. , 60. ]])

Code:

np.arange(10 ,50, 5)

Output:

array([10, 15, 20, 25, 30, 35, 40, 45])

Code:

np.arange(0, 3, .4)

Output:

array([0. , 0.4, 0.8, 1.2, 1.6, 2. , 2.4, 2.8])

Code:

from numpy import pi
np.linspace(0, 2, 9)

Output:

array([ 0.  ,  0.25,  0.5 ,  0.75,  1.  ,  1.25,  1.5 ,  1.75,  2.  ])

Code:

x = np.linspace(0, 2*pi, 50)
f = np.sin(x)
x

Output:

array([0.        , 0.12822827, 0.25645654, 0.38468481, 0.51291309,
       0.64114136, 0.76936963, 0.8975979 , 1.02582617, 1.15405444,
       1.28228272, 1.41051099, 1.53873926, 1.66696753, 1.7951958 ,
       1.92342407, 2.05165235, 2.17988062, 2.30810889, 2.43633716,
       2.56456543, 2.6927937 , 2.82102197, 2.94925025, 3.07747852,
       3.20570679, 3.33393506, 3.46216333, 3.5903916 , 3.71861988,
       3.84684815, 3.97507642, 4.10330469, 4.23153296, 4.35976123,
       4.48798951, 4.61621778, 4.74444605, 4.87267432, 5.00090259,
       5.12913086, 5.25735913, 5.38558741, 5.51381568, 5.64204395,
       5.77027222, 5.89850049, 6.02672876, 6.15495704, 6.28318531])

Code:

f

Output:

array([  0.00000000e+00,   6.34239197e-02,   1.26592454e-01,
         1.89251244e-01,   2.51147987e-01,   3.12033446e-01,
         3.71662456e-01,   4.29794912e-01,   4.86196736e-01,
         5.40640817e-01,   5.92907929e-01,   6.42787610e-01,
         6.90079011e-01,   7.34591709e-01,   7.76146464e-01,
         8.14575952e-01,   8.49725430e-01,   8.81453363e-01,
         9.09631995e-01,   9.34147860e-01,   9.54902241e-01,
         9.71811568e-01,   9.84807753e-01,   9.93838464e-01,
         9.98867339e-01,   9.99874128e-01,   9.96854776e-01,
         9.89821442e-01,   9.78802446e-01,   9.63842159e-01,
         9.45000819e-01,   9.22354294e-01,   8.95993774e-01,
         8.66025404e-01,   8.32569855e-01,   7.95761841e-01,
         7.55749574e-01,   7.12694171e-01,   6.66769001e-01,
         6.18158986e-01,   5.67059864e-01,   5.13677392e-01,
         4.58226522e-01,   4.00930535e-01,   3.42020143e-01,
         2.81732557e-01,   2.20310533e-01,   1.58001396e-01,
         9.50560433e-02,   3.17279335e-02,  -3.17279335e-02,
        -9.50560433e-02,  -1.58001396e-01,  -2.20310533e-01,
        -2.81732557e-01,  -3.42020143e-01,  -4.00930535e-01,
        -4.58226522e-01,  -5.13677392e-01,  -5.67059864e-01,
        -6.18158986e-01,  -6.66769001e-01,  -7.12694171e-01,
        -7.55749574e-01,  -7.95761841e-01,  -8.32569855e-01,
        -8.66025404e-01,  -8.95993774e-01,  -9.22354294e-01,
        -9.45000819e-01,  -9.63842159e-01,  -9.78802446e-01,
        -9.89821442e-01,  -9.96854776e-01,  -9.99874128e-01,
        -9.98867339e-01,  -9.93838464e-01,  -9.84807753e-01,
        -9.71811568e-01,  -9.54902241e-01,  -9.34147860e-01,
        -9.09631995e-01,  -8.81453363e-01,  -8.49725430e-01,
        -8.14575952e-01,  -7.76146464e-01,  -7.34591709e-01,
        -6.90079011e-01,  -6.42787610e-01,  -5.92907929e-01,
        -5.40640817e-01,  -4.86196736e-01,  -4.29794912e-01,
        -3.71662456e-01,  -3.12033446e-01,  -2.51147987e-01,
        -1.89251244e-01,  -1.26592454e-01,  -6.34239197e-02,
        -2.44929360e-16])