Given a stream of elements too large to store in memory, pick a random element from the stream with uniform probability.

Daily_coding_Problem_15.py

import random
def pick_random(l):
    '''
    l(list) : imagine stream is passed as list 
              in loop
    '''
    count=1
    x=l[0]
    print(x)
    for i in l[1:]:
        count+=1
        el=random.randrange(0,count)
        if el is count-1:
            x=i
        print(x)
        
'''
Input:
------
pick_random(l=[4,2,5,2,1,2])

output:
-------
4
2
5
5
1
1
'''