How do you pick "x" number of unique numbers from a list in Python?

Question

I need to pick out "x" number of non-repeating, random numbers out of a list. For example:

all_data = [1, 2, 2, 3, 4, 5, 6, 7, 8, 8, 9, 10, 11, 11, 12, 13, 14, 15, 15] 

How do I pick out a list like [2, 11, 15] and not [3, 8, 8]?

Answer 1

That's exactly what random.sample() does.

>>> random.sample(range(1, 16), 3) [11, 10, 2] 

Edit: I'm almost certain this is not what you asked, but I was pushed to include this comment: If the population you want to take samples from contains duplicates, you have to remove them first:

population = [1, 2, 3, 4, 5, 6, 5, 4, 3, 2, 1] population = set(population) samples = random.sample(population, 3) 

Answer 2

Something like this:

all_data = [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15] from random import shuffle shuffle(all_data) res = all_data[:3]# or any other number of items 

OR:

from random import sample number_of_items = 4 sample(all_data, number_of_items) 

If all_data could contains duplicate entries than modify your code to remove duplicates first and then use shuffle or sample:

all_data = list(set(all_data)) shuffle(all_data) res = all_data[:3]# or any other number of items