# importing libraries
import numpy as np
 
# sort along the first axis
a = np.array([[12, 15], [10, 1]])
arr1 = np.sort(a, axis = 0)       
print ("Along first axis : \n", arr1)       
 
 
# sort along the last axis
a = np.array([[10, 15], [12, 1]])
arr2 = np.sort(a, axis = -1)       
print ("\nAlong first axis : \n", arr2)
 
 
a = np.array([[12, 15], [10, 1]])
arr1 = np.sort(a, axis = None)       
print ("\nAlong none axis : \n", arr1)

Along first axis : 
 [[10  1]
 [12 15]]

Along first axis : 
 [[10 15]
 [ 1 12]]

Along none axis : 
 [ 1 10 12 15]

import numpy as np
 
# Numpy array created
a = np.array([9, 3, 1, 7, 4, 3, 6])
 
# unsorted array print
print('Original array:\n', a)
 
# Sort array indices
b = np.argsort(a)
print('Sorted indices of original array->', b)
 
# To get sorted array using sorted indices
# c is temp array created of same len as of b
c = np.zeros(len(b), dtype = int)
for i in range(0, len(b)):
    c[i]= a[b[i]]
print('Sorted array->', c)

Original array:
 [9 3 1 7 4 3 6]
Sorted indices of original array-> [2 1 5 4 6 3 0]
Sorted array-> [1 3 3 4 6 7 9]

import numpy as np
 
# Numpy array created
# First column
a = np.array([9, 3, 1, 3, 4, 3, 6])
 
# Second column
b = np.array([4, 6, 9, 2, 1, 8, 7])
print('column a, column b')
for (i, j) in zip(a, b):
    print(i, ' ', j)
 
# Sort by a then by b
ind = np.lexsort((b, a))
print('Sorted indices->', ind)

column a, column b
9   4
3   6
1   9
3   2
4   1
3   8
6   7
Sorted indices-> [2 3 1 5 4 6 0]