numpy.random — Generating Random Numbers In Python

Random number have lots of application like, cryptography, game and Neural Network. Here we’ll discuss and identify different methods for generating random numbers in NumPy module in python.

import numpy as np

numpy.random.random (size)— Return random floats in the half-open interval [0.0, 1.0), ie 1.0>x≥0.0

>>>np.random.random((2,2))
array([[ 0.66032591,  0.91397527],
       [ 0.63366556,  0.36594058]])

numpy.random.randint(low, high, size, dtype=int) — Return random integers from low to high from the “discrete uniform” distribution.

>>> np.random.randint([1, 3, 5, 7], [[10], [20]], dtype=np.uint8)
array([[ 8,  6,  9,  7], 
       [ 1, 16,  9, 12]], dtype=uint8)

numpy.random.randn(d1,d2,..dn) — Return a sample/s from the “standard normal” distribution, for given dimension.

>>> np.random.randn(2,2)
array([[ 0.6762164 , -1.37066901],
       [ 0.23856319,  0.61407709]])

numpy.random.rand(s1,s2,..sn) — Random values in a given given dimension and ranges between (0,1).

>>> np.random.rand(3,2)
array([[ 0.14022471,  0.96360618],  
       [ 0.37601032,  0.25528411],  
       [ 0.49313049,  0.94909878]]) 

random.rand and random.randn are similar function, both in functionality and syntax and can be confused easily.
random.rand — Returns sample according to standard normal distribution.
random.randn — Returns numbers ranging between (0,1)

numpy.random.normal(loc=0.0, scale=1.0, size=None) — Draw random samples from a normal (Gaussian) distribution.

loc : Mean (“centre”) of the distribution
scale : spread or “width” of the distribution
>>> np.random.normal(3, 2.5, size=(2, 4))
array([[-4.49401501,  4.00950034, -1.81814867,  7.29718677],   
       [ 0.39924804,  4.68456316,  4.99394529,  4.84057254]])  

These are the most methods used for creating random number. More details can be searched in documentation. To get broader knowledge on numpy check my article.

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