def word(s1,s2):

   index = 0
   while index < len(s1):
       if s2 in range(len(s1)):
           s1[index] = s1[index] * index
       index = index  1
   return s1


print(word("aratehadb", "a"))

I want the code to return "raatehaaaaaadb" meaning I want it to multiply the chosen letter with the index its found at, I have tried res = [i for i in range(len(s1)) if s1.startswith(s2, i)] to find the positions that the letters are at but I'm stuck at how I multiply with the index

CodePudding user response：

Use enumerate

You can use enumerate to obtain the index of each value, determine if the letter matches what you want to multiply and do the multiplication if required.

def word(s1, s2):
    return ''.join([l*i if l == s2 else l for i, l in enumerate(s1)])

print(word("aratehadb", "a"))
# raatehaaaaaadb

Closer from your first implementation

def word(s1, s2):
    index = 0
    # string can't be mutated (changed) so we need to create 
    # a list to change each character string and make it bigger 
    # if needed
    l_s1 = list(s1)
    while index < len(s1):
        if s2 == s1[index]:
            # Here you can replace s1 with l_s1, we access the same string anyway.
            # Also, l_s1[index] *= index also works
            l_s1[index] = s1[index] * index
        index = index   1
    return ''.join(l_s1)

print(word("aratehadb", "a"))
# raatehaaaaaadb

str.join() documentation