Replacing an element of a 2D matrix with a random number in python

Question

I have a 2D matrix A=[[27 1 63 66 79],[55 20 40 26 68],[42 64 96 27 14]]. I want to replace every element greater than 20 with a random number. Is there a way to replace it with a new random number every time a entry greater than 20 is detected. I don't want to use the for loop and iterate over each entry. I am using this A[A>20]= np.random.randint(0,9). However in this technique each entry greater than 20 is replaced with a fixed random number.

Would you mind adding the commas to your lists so they become actual lists — Chris
– Chris, Commented Dec 23, 2021 at 17:27
Does this answer your question? Replace numpy array value on condition with random number — Chris
– Chris, Commented Dec 23, 2021 at 17:29

mozway · Accepted Answer · 2021-12-23 17:42:13Z

1

Assuming you have a numpy array. You need to generate a random array of the same shape.

A = np.where(A>20, np.random.randint(0,9, size=A.shape), A)

Example output:

array([[0, 8, 3, 0, 2],
       [1, 4, 7, 5, 1],
       [5, 4, 8, 7, 6]])

edited Dec 23, 2021 at 17:42

answered Dec 23, 2021 at 17:30

mozway

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1 Comment

Hamza Abbasi Over a year ago

This worked fine!

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