Prepend a string in Python

Question

I'm trying to prepend zeros to each number in a list if it isn't a the necessary number of digits.

    lst = ['1234','2345']
    for x in lst:
        while len(x) < 5:
            x = '0' + x
    print(lst)

Ideally this would print ['012345', '02345']

Answer 1

Ultimately, it was a combination of the answers that did the job.

lst = ['1234','2345']
newlst = []

for i in lst:
    i = i.zfill(5)
    newlst.append(i)

print(newlst)

I apologize if my example wasn't clear. Thank you to all who offered answers!