CODEWITHSUNDEEP
arraysnumpyfor-loop
user18605114
user18605114

Reputation:

How can i create 2 for loops to replace values in Numpy array?

How can i use two for loops to replace the values in x with the row number, starting at 1, so it should be [[1,1,1,1,1],[2,2,2,2,2] … [5,5,5,5,5]]

x=np.ones((5,5)) print(x)

Thanks

Upvotes: 0

Views: 23

Answers (1)

mozway
mozway

Reputation: 260690

Don't use for loops in numpy, use broadcasting:

x=np.ones((5,5))

x[:] = np.arange(x.shape[0])[:, None]+1

Updated x:

array([[1., 1., 1., 1., 1.],
       [2., 2., 2., 2., 2.],
       [3., 3., 3., 3., 3.],
       [4., 4., 4., 4., 4.],
       [5., 5., 5., 5., 5.]])

Alternatives:

x[:] = np.arange(x.shape[0])[:, np.newaxis]+1

Or:

x[:] = np.arange(x.shape[0]).reshape(-1, 1)+1

Upvotes: 2

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