toUpperCase at specific index uppercases more chars than supposed to

Question

I'm trying to solve a problem that takes specific symbols and removes them from the string, then it converts the character following that symbol to uppercase. But for some reason characters after the uppercased characters are also getting uppercased.

s is the given string.

String[] symbols = { "-", "_" };
int index = 0;   

for(String symbol : symbols) {
  while(s.indexOf(symbol) >= 0){
    index = s.indexOf(symbol);
    s = s.replaceFirst(symbol, "");
    s = s.replace(s.charAt(index), Character.toUpperCase(s.charAt(index)));
    System.out.println(index);
  }
}

The given input is: river_Green_Green_Wall_Lake_left_Samurai_Wall

What I expected was: riverGreenGreenWallLakeLeftSamuraiWall

But what I got instead is: riverGreenGreenWaLLLakeLeftSamuraiWaLL

The method ```replace``` replaces all occurrences of the given string. This is not what you want. Since there is no ```replaceFirst``` with a starting index, you might need to use some ```substring``` calls in combination with it to achieve your goal. — Islingre, Oct 17 '19 at 14:56
Possible duplicate of [Replace a character at a specific index in a string?](https://stackoverflow.com/questions/6952363/replace-a-character-at-a-specific-index-in-a-string) — Armali, Oct 17 '19 at 15:11

score 1 · Accepted Answer · answered Oct 17 '19 at 15:08

1

rather than using replace, you should try rebuilding the string with the index uppercased

    for(String symbol : symbols) {
      while(s.indexOf(symbol) >= 0){
        index = s.indexOf(symbol);
        //
        s = s.substring(0,index)+s.substring(index+1,index+2).toUpperCase()+s.substring(index+2);
        //
        System.out.println(s);
      }
    }

answered Oct 17 '19 at 15:08

Tom Chumley

144
5

3

It would be better to do this with a `StringBuilder`, since this would avoid continually rebuilding and discarding the string: you can use `StringBuilder.indexOf` to find the character, and then `StringBuilder.set` to change it. – Andy Turner Oct 17 '19 at 15:10

score 1 · Answer 2 · answered Oct 17 '19 at 15:14

just you need call replace method in the same line when you replace symbol:

    String s ="river_Green_Green_Wall_Lake_left_Samurai_Wall";
    String[] symbols = { "-", "_" };
    int index = 0;

  for(String symbol : symbols) {
     while(s.indexOf(symbol) >= 0){
       index = s.indexOf(symbol);
       s = s.replaceFirst(symbol, "").replace(s.charAt(index) ,Character.toUpperCase(s.charAt(index)));
      }
    }
    System.out.println(s);
}

toUpperCase at specific index uppercases more chars than supposed to

2 Answers2