Non-repetitive random number in numpy

Question

How can I generate non-repetitive random numbers in numpy?

list = np.random.random_integers(20,size=(10))

Answer 1

numpy.random.Generator.choice offers a replace argument to sample without replacement:

from numpy.random import default_rng

rng = default_rng()
numbers = rng.choice(20, size=10, replace=False)

If you're on a pre-1.17 NumPy, without the Generator API, you can use random.sample() from the standard library:

print(random.sample(range(20), 10))

You can also use numpy.random.shuffle() and slicing, but this will be less efficient:

a = numpy.arange(20)
numpy.random.shuffle(a)
print a[:10]

There's also a replace argument in the legacy numpy.random.choice function, but this argument was implemented inefficiently and then left inefficient due to random number stream stability guarantees, so its use isn't recommended. (It basically does the shuffle-and-slice thing internally.)