CODEWITHSUNDEEP
javastringreplacecharacter
Inti Velasquez
Inti Velasquez

Reputation: 25

How to replace a point ('.') in a string, with the word before the point?

If we have 

String x="Hello.World";

I'm looking to replace that '.' with "Hello", as to have: "HelloHelloWorld".

The problem is, if I have:

String Y="Hello.beautiful.world.how.are.you;"

the answer would have to be "HelloHellobeautifulbeautifulworldworldhowhowareareyouyou"

Keep in mind that I can't use arrays.

Upvotes: 1

Views: 196

Answers (3)

Inti Velasquez
Inti Velasquez

Reputation: 25

This is what i have:

public String meowDot(String meow){
    int length = meow.length();
    String beforeDot = "";
    String afterDot;
    char character;
    for(int i=0; i < length; i++){
        character = meow.charAt(i);
        if (i < largo - 1 && character == '.'){
            beforeDot += meow.substring(0, i) + meow.substring(0, i);
            afterDot = meow.substring(i, length);
            meow = afterDot;
        } else if(i == length - 1 && character != '.'){
            afterDot += meow + meow;
        }          
    }
    return beforeDot;
}

Upvotes: -2

Mike Elofson
Mike Elofson

Reputation: 2037

Think of the problem like a pointer problem. You need to keep a running pointer pointed at the last place you looked (firstIndex in my code), and a pointer at your current place (nextIndex in my code). Call subString() on whatever is between those places (add 1 to firstIndex after the first occurrence because we don't need to capture the "."), append it twice to a new string, and then change your pointers. There is probably a more elegant solution but, this gets the job done:

    String Y="Hello.beautiful.world.how.are.you";
    int firstIndex=0;
    int nextIndex=Y.indexOf(".",firstIndex);

    String newString = "";
    while(nextIndex != -1){
        newString += Y.substring(firstIndex==0 ? firstIndex : firstIndex+1, nextIndex);
        newString += Y.substring(firstIndex==0 ? firstIndex : firstIndex+1, nextIndex);
        firstIndex=nextIndex;
        nextIndex=Y.indexOf(".", nextIndex+1);
    }

    System.out.println(newString);

Output:

HelloHellobeautifulbeautifulworldworldhowhowareare

Upvotes: 1

Lykos
Lykos

Reputation: 1029

I think you can just use regex replacements to achieve that. In a regex, you can use so called "capture groups". You match a word plus a dot with your regex and then you replace it with two times the matched word.

// Match any number of word characters plus a dot
Pattern regex = Pattern.compile("(\\w*)\\.");

Matcher regexMatcher = regex.matcher(text);

// $1 is the matched word, so $1$1 is just two times that word.
resultText = regexMatcher.replaceAll("$1$1");

Note that I didn't try it out since it would probably take me half an hour to set up the Java environment etc. But I am pretty confident that it works.

Upvotes: 3

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