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

To shuffle this NumPy array:


        
        
            
                
                
                    rng = np.random.default_rng()
rng.shuffle(x)
x
                
            
            array([4, 0, 2, 9, 6, 3, 1, 5, 8, 7])

Notice how the shuffle is done in-place.

Setting axis

Consider the following two-dimensional array:


        
        
            
                
                
                    x = np.arange(12).reshape((3,4))
x
                
            
            array([[ 0,  1,  2,  3],
       [ 4,  5,  6,  7],
       [ 8,  9, 10, 11]])

By default, axis=0, which means that rows are shuffled:


        
        
            
                
                
                    rng = np.random.default_rng(seed=42)
rng.shuffle(x)   # axis=0
x
                
            
            array([[ 8,  9, 10, 11],
       [ 4,  5,  6,  7],
       [ 0,  1,  2,  3]])

To shuffle the columns, set axis=1:


        
        
            
                
                
                    rng.shuffle(x, axis=1)
x
                
            
            array([[ 2,  0,  3,  1],
       [ 6,  4,  7,  5],
       [10,  8, 11,  9]])

Setting a seed

In order to be able to reproduce the randomness, set a seed like so:


        
        
            
                
                
                    rng = np.random.default_rng(seed=42)
x = np.arange(10)
rng.shuffle(x)
x
                
            
            array([5, 6, 0, 7, 3, 2, 4, 9, 1, 8])

Published by Isshin Inada

Edited by 0 others

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Official NumPy Documentation

https://numpy.org/doc/stable/reference/random/generated/numpy.random.Generator.shuffle.html

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