How can I generate random numbers based on a pattern from a given list of numbers?

I'm trying to generate x random numbers based on lists I will provide (containing the same amount of numbers I want generated). So Far I have this code:

import random
list = []

while len(list) < 10:
    x = random.randint(1, 100)
    if x not in list:
        list.append(x)

list.sort()
print (list)

The question is, how do I input the lists I have so Python can read some pattern (in lack of a better word) and generate numbers? Tried Google it, found nothing so far. Thanks.