Java: Replace a specific character with a substring in a string at index

Question

I am struggling with how to actually do this. Say I have this string

"This Str1ng i5 fun"

I want to replace the '1' with "One" and the 5 with "Five"

"This StrOneng iFive fun"

I have tried to loop thorough the string and manually replace them, but the count is off. I have also tried to use lists, arrays, stringbuilder, etc. but I cannot get it to work:

char[] stringAsCharArray = inputString.toCharArray();
ArrayList<Character> charArraylist = new ArrayList<Character>();

for(char character: stringAsCharArray) {
    charArraylist.add(character);
}

int counter = startPosition;

while(counter < endPosition) {
    char temp = charArraylist.get(counter);
    String tempString = Character.toString(temp);
    if(Character.isDigit(temp)){
        char[] tempChars = digits.getDigitString(Integer.parseInt(tempString)).toCharArray(); //convert to number

        charArraylist.remove(counter);
        int addCounter = counter;
        for(char character: tempChars) {
            charArraylist.add(addCounter, character);
            addCounter++;
        }

        counter += tempChars.length;
        endPosition += tempChars.length;
    }
    counter++;
}

I feel like there has to be a simple way to replace a single character at a string with a substring, without having to do all this iterating. Am I wrong here?

Community · Accepted Answer · 2017-05-23 12:16:21Z

2

String[][] arr = {{"1", "one"}, 
                           {"5", "five"}};

String str = "String5";
for(String[] a: arr) {
    str = str.replace(a[0], a[1]);
}

System.out.println(str);

This would help you to replace multiple words with different text.

Alternatively you could use chained replace for doing this, eg :

str.replace(1, "One").replace(5, "five");

Check this much better approach : Java Replacing multiple different substring in a string at once (or in the most efficient way)

edited May 23, 2017 at 12:16

CommunityBot

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answered Sep 7, 2016 at 0:44

Rishi

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Comments

Thilo · Accepted Answer · 2016-09-07 00:39:08Z

2

You can do

string = string.replace("1", "one");

Don't use replaceAll, because that replaces based on regular expression matches (so that you have to be careful about special characters in the pattern, not a problem here).
Despite the name, replace also replaces all occurrences.
Since Strings are immutable, be sure to assign the result value somewhere.

answered Sep 7, 2016 at 0:39

Thilo

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Comments

Arnav Borborah · Accepted Answer · 2016-09-07 00:44:34Z

1

Try the below:

string = string.replace("1", "one");
string = string.replace("5", "five");

.replace replaces all occurences of the given string with the specified string, and is quite useful.

answered Sep 7, 2016 at 0:44

Arnav Borborah

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