Codewars notes - 替换数字

exercise:

Given a string of digits, you should replace any digit below 5 with '0' and any digit 5 and above with '1'. Return the resulting string.

Note: input will never be an empty string

Solution:

def fake_bin(x):
    s2 = ''
    
    for i in x:
        if int(i) >= 5:
            i = "1"
            s2 += i
        else:
            i = "0"
            s2 += i
    return s2