numpy first column code example

Example 1: print column in 2d numpy array

import numpy as np
x=np.arange(25).reshape(5,5)
print(x)
#print(x[:,index_of_column_you_need])
print(x[:,3])

Example 2: how to get the first few lines of an ndarray 3d

>>> import numpy as np
>>> v = np.array(np.arange(24)).reshape(2,3,4)
>>> v
array([[[ 0,  1,  2,  3],
        [ 4,  5,  6,  7],
        [ 8,  9, 10, 11]],

       [[12, 13, 14, 15],
        [16, 17, 18, 19],
        [20, 21, 22, 23]]])
>>> v[:, 1, 3]
array([ 7, 19])