Python Create Array
NumPy provides a variety list of functions for creating arrays.
np array
Creating Arrays from Python Sequences
You can create an array from a Python list or tuple by using NumPy’s array function.(2,3 – shaped array)
numpy sequence
import numpy as np print(np.array([[1, 4, 6], [3, 5, 7]]))
# [ # [1 4 6] # [3 5 7] # ]
Creating 1 dim array with zeros
NumPy provides the functions zeros and ones, which will fill an array of user-specified shape with 0s and 1s.
import numpy as np print(np.zeros(5)) print(np.ones(5))
Output
[0. 0. 0. 0. 0.] [1. 1. 1. 1. 1.]
Creating new array with 4 rows and 3 columns
[0]*3 will produce [0, 0, 0].
import numpy as np print(np.array([[0*4]*3])) print(np.array([[0*4]*3]*2))
# [ # [0 0 0] # ] # [ # [0 0 0] # [0 0 0] # ]
Generate Array Python
import numpy as np print(np.zeros((4, 3)))
Output
[ [0. 0. 0.] [0. 0. 0.] [0. 0. 0.] [0. 0. 0.] ]
Create a square N × N identity matrix
import numpy as np print(np.eye(4))
Output
[ [1. 0. 0. 0.] [0. 1. 0. 0.] [0. 0. 1. 0.] [0. 0. 0. 1.] ]
numpy make array
Several functions can be accessed from np.random, which derived arrays randomly.
Creates uniform random numbers
import numpy as np print(np.random.random((2, 2)))
Output
[ [ 0.05802877 0.36875017] [ 0.52098717 0.02762662] ]
Creates random integer (from – to)
import numpy as np print(np.random.randint(5, 15, (4, 4)))
Output
[ [10 14 10 6] [ 7 6 6 7] [ 7 11 7 12] [10 8 7 10] ]
Joining the Arrays Numpy
numpy create array
import numpy as np x = np.array([1, 2, 3]) y = np.array([-1, -2, -3]) print(np.vstack([x, y])) print(np.hstack([x, y]))
# [ # [ 1 2 3] # [-1 -2 -3] # ] # [ 1 2 3 -1 -2 -3]