Is there a need for range(len(a))?

Question

One frequently finds expressions of this type in python questions on SO. Either for just accessing all items of the iterable

for i in range(len(a)):
    prin         


        

Answer 1

My code is:

s=["9"]*int(input())
for I in range(len(s)):
    while not set(s[I])<=set('01'):s[i]=input(i)
print(bin(sum([int(x,2)for x in s]))[2:])

It is a binary adder but I don't think the range len or the inside can be replaced to make it smaller/better.