• Source 
    1. s = list(str("aaabbcc"))
    2.  
    3. a, b, c, d = 0, 0, 0, 0
    4. for i in s:
    5.     if i == 'a':
    6.         a += 1
    7.         del s[0]
    8.  
    9. print(s)
    10. print(a, b, c, d)