Create a numpy array with zeros and ones at random positions

Question

I'm using Python 3.7.7.

I want to create a Numpy array with random values between 1 and 0. I have found that I can create an array with all of its elements equal to zero:

zeros = np.zeros((960, 200, 200, 1))

Or equal to one:

ones = np.ones((960, 200, 200, 1))

Those functions return an array with all of its elements equals.

I want to create an array with its elements are zero or one at random positions.

How can I do it?

Are you trying to create an array with zeros and ones at random positions? — FBruzzesi
– FBruzzesi, Commented Aug 17, 2020 at 12:46
Randon values between 0 and 1: maybe you want this? numpy.org/doc/stable/reference/random/generated/… — Valentino
– Valentino, Commented Aug 17, 2020 at 12:47

efont · Accepted Answer · 2020-08-17 12:57:02Z

5

This can be achieved in many ways using numpy, the most straightforward being:

size = (960, 200, 200, 1)
np.random.randint(0, 2, size=size)

If you don't want uniform distribution of zeros and ones, this can be controlled directly using numpy.random.choice:

size = (960, 200, 200, 1)
proba_0 = 0.8                 # resulting array will have 80% of zeros
np.random.choice([0, 1], size=size, p=[proba_0, 1-proba_0])

answered Aug 17, 2020 at 12:57

efont

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warped · Accepted Answer · 2020-08-17 12:48:40Z

1

you can draw numbers from [0,1] and ask if they are larger than a threhold value:

threshold = 0.5
a = 1*(np.random.rand(960, 200, 200, 1)> threshold)

answered Aug 17, 2020 at 12:48

warped

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