第一次分配后继续循环

Question

我对循环的处理有疑问。这是适用于Python的子手的代码。尽管对每个角色使用列表或仅打印似乎是执行任务的更简便方法，但我想知道，为了避免将来遇到的麻烦，提出的解决方案的问题在哪里。

word='heksakosjokontaheksafobia'

def hangman(input, word_to_guess):
    users_guess=input('What is the first letter of your first thought?\n')
    print (users_guess)
    if users_guess in word_to_guess:
        unknown_chararcters='*'*len(word_to_guess) # The creation of a string showing number of uknown characters
        print(unknown_characters)
        for char in word_to_guess:
            if char==users_guess: # Checking whether input is included in word_to_guess
                ind=word_to_guess.index(char)
                unknown_characters=unknown_characters[:ind]+users_guess+unknown_characters[ind+1:] # Substitution of '*' with input
            continue
        print(unknown_characters)
hangman(input, word)

如您所见，单词包含许多'a'，但是对于input == a，输出为：

What is the first letter of your first thought?
a
*************************
****a********************

如何强制循环遍历字符串的以下字符？