Java replacing char at index

Question

I'm wanting to replace a character at in a string

Answer 1

You could accomplish this by using substring() to pick apart and recreate the string, but another way is to just convert it to a char[] and operate on that, e.g.:

char[] data = captureString[0].toCharArray();
data[strOneRand] = Character.toUpperCase(data[strOneRand]); // or whatever
String outputFinal = new String(data);

An example of accomplishing this with substring() can be found in the accepted answer of Replace a character at a specific index in a string?. An example of doing it with a StringBuilder can be found there as well.

Answer 2

you just need to do this

char[] charArray = captureString[0].toCharArray();
charArray[strOneRand] = THE_NEW_CHARECTOR_YOU_WANT_TO_REPLACE;
String outputFinal = String.copyValueOf(charArray);

Answer 3

you can also use the utility class StringBuilder like this:

    StringBuilder resultString = new StringBuilder(captureString[0]);
    char replaceMe = captureString[0].charAt(strOneRand);
    resultString.setCharAt(strOneRand, Character.toUpperCase(replaceMe));

    System.out.println(resultString.toString());

The assignment is just for clarification, good luck!

Answer 4

String a = captureString[0].substring(0,strOneRand);
String b = captureString[0].substring(strOneRand,strOneRand+1).toUpperCase;
String c = captureString[0].substring(strOneRand+1);

System.out.println(a+b+c);

replace method will make the first occurrence of chosen character to upper case. if input string is "aaaaa", you will always get "Aaaaa".

Answer 5

Here is what I would do in your situation:

public void replaceChar(String strPassed, int index){

    char strArray[] = strPassed.toCharArray(); 
    strArray[index] = (char)(strArray[index] - 32);
    strPassed[0] = new String(strArray);

}

and then wherever I wanted to convert the character into UpperCase:

replaceChar(capturString[0], strOneRand);