np.random.permutation with seed?

Question

I want to use a seed with np.random.permutation, like

np.random.permutation(10, seed=42) 

I get the following error:

"permutation() takes no keyword arguments" 

How can I do that else? Thanks.

Answer 1

If you want it in one line, you can create a new RandomState, and call the permutation on that:

np.random.RandomState(seed=42).permutation(10) 

This is better than just setting the seed of np.random, as it will have only a localized effect.

Answer 2

np.random.seed(42) np.random.permutation(10) 

If you want to call np.random.permutation(10) multiple times and get identical results, you also need to call np.random.seed(42) every time you call permutation().

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For instance,

np.random.seed(42) print(np.random.permutation(10)) print(np.random.permutation(10)) 

will produce different results:

[8 1 5 0 7 2 9 4 3 6] [0 1 8 5 3 4 7 9 6 2] 

while

np.random.seed(42) print(np.random.permutation(10)) np.random.seed(42) print(np.random.permutation(10)) 

will give the same output:

[8 1 5 0 7 2 9 4 3 6] [8 1 5 0 7 2 9 4 3 6]