np.random.permutation 与种子？

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() .

---

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]

Answer 3

Set the seed in the previous line

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

Answer 4

You can break it down into:

import numpy as np
np.random.seed(10)
np.random.permutation(10)

By initializing the random seed first, this will guarantee that you get the same permutation.