How can i replace index of string of underscores with other word or character?

Question

word = "_" * 10
word = word.replace(word[5], "a")

O/p
aaaaaaaaaa
This is not working ..why?

Answer 1

You want to modify only word[5]?

In the case:

word = word[:5] + "a" + word[6:]

Answer 2

You can always just convert word to a list. Then join it back to a string when you're done modifying it.

word = "_" * 10
word = list(word)
word[5] = 'a'
print(''.join(word))

Answer 3

`replace` method replaces all the given first argument by the given second argument.

Your string initially was "__________" (10 times an underscore), so when you call replace(word[5], "a") you are actually replacing any "_" in string <word> by "a".