Filling a numpy array with x random values

Question

I have a numpy array of size x, which I need to fill with 700 true.

For example:

a = np.zeros(5956)

If I want to fill this with 70 % True, I can write this:

msk = np.random.rand(len(a)) < 0.7
b = spam_df[msk]

But what if I need exactly 700 true, and the rest false?

Answer 1

import numpy as np

x = 5956
a = np.zeros((x), dtype=bool)

random_places = np.random.choice(x, 700, replace=False)
a[random_places] = True