How to randomly set elements in numpy array to 0

Question

First I create my array

myarray = np.random.random_integers(0,10, size=20)

Then, I want to set 20% of the elements in the array to 0 (or some o

Answer 1

Use np.random.permutation as random index generator, and take the first 20% of the index.

myarray = np.random.random_integers(0,10, size=20)
n = len(myarray)
random_idx = np.random.permutation(n)

frac = 20 # [%]
zero_idx = random_idx[:round(n*frac/100)]
myarray[zero_idx] = 0