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+--- Thread: Numpy random number (/thread-4093.html)
Numpy random number - Bryant - Jul-22-2017
I am a beginner of Python. And I am a bit confused by different way of generating random numbers. Appreciate if anyone can explain the difference below:
import numpy as np a1 = np.random.random((1,4)) a2 = np.random.random(4)Thank you!
RE: Numpy random number - MTVDNA - Jul-23-2017
The difference is in the output: a2 returns an array of 4 floats, whereas a1 returns a 1x4 multidimensional array of floats, the first dimension in this case being 1.
If you print the output you'll get something like this:
import numpy as np
a1 = np.random.random((1,4))
a2 = np.random.random(4)
print("a1:", a1)
print("a2:", a2)Output:a1: [[ 0.59946856 0.98460562 0.2970344 0.93185208]]
a2: [ 0.84642216 0.76289462 0.02371878 0.48856006]# first value of first array in a1 r1= a1[0][0] # first value of a2 r2 = a2[0]You can add as many dimensions as you like:
# make a 2 x 4 multidimensional array of random floats
a3 = np.random.random((2,4))
print(a3)
print("")
# make a 2 x 3 x 4 multidimensional array of random floats
a4 = np.random.random((2,3,4))
print(a4)Output:[[ 0.24597847 0.31471039 0.66878251 0.12768539]
[ 0.82398123 0.97512768 0.39540696 0.43854987]]
[[[ 0.27224315 0.77992856 0.54579919 0.24076665]
[ 0.56690179 0.2984007 0.4736477 0.45876745]
[ 0.31631711 0.8529202 0.10593129 0.44203135]]
[[ 0.47631484 0.76030139 0.31148261 0.81140939]
[ 0.71954076 0.98883936 0.97953863 0.01995996]
[ 0.54762994 0.73041063 0.8126263 0.11215006]]]https://docs.scipy.org/doc/numpy/reference/generated/numpy.random.random.html