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Ritvik Dubey
Ritvik Dubey

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Java replace() Method

Hello all๐Ÿ‘‹ I hope you are doing well. This is going to be a very short and very useful article. In this article I'll be writing about replace() method in Java. This is a one of the most useful methods.

Let's begin...

replace()

The replace() method will replace a character or substring with another character or string. This is a method of Java String class. It returns a string derived from the original string by replacing every occurrence of old-string or old-character with new-string or new-character. When working with a string in Java, you may encounter a situation where you want to replace a specific character or substring in that string with another character or another substring. In such situations replace() method comes in.

Syntax :-

stringName.replace(oldString, newString);
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There are many variations in which replace() can be used.

1. replace(char oldChar, char newChar)

In this example we have replaced all the occurrences of char โ€˜lโ€™ with char โ€˜c'.

public class Demo {
    public static void main(String[] args) {
        String strOld = "Hello world";
        System.out.println("Original string : " + strOld);
        String strNew = strOld.replace('l','c');
        System.out.println("Replaced string : " + strNew);
    }
}
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java-replace().png

2. replace(String oldString, String newString)

In this example we have replaced all the occurrence of String "lo" with String "ping".

public class Demo {
    public static void main(String[] args) {
        String strOld = "Hello world";
        System.out.println("Original string : " + strOld);
        String strNew = strOld.replace("lo","ping");
        System.out.println("Replaced string : " + strNew);
    }
}
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java-replace()-1.png

3. replace(String emptyString, String newString)

In this example we have replaced all the occurrence of String "" (empty String) with String "A".

public class Demo {
    public static void main(String[] args) {
        String strOld = "Hello world";
        System.out.println("Original string : " + strOld);
        String strNew = strOld.replace("", "A");
        System.out.println("Replaced string : " + strNew);
    }
}
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java-replace()-2.png

4. replace(String whitespace, String newString)

public class Demo {
    public static void main(String[] args) {
        String strOld = "Hello world";
        System.out.println("Original string : " + strOld);
        String strNew = strOld.replace(" ", "WHITESPACE");
        System.out.println("Replaced string : " + strNew);
    }
}
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java-replace()-3.png

5. replaceFirst(String oldString, String newString)

public class Demo {
    public static void main(String[] args) {
        String strOld = "Hello world";
        System.out.println("Original string : " + strOld);
        String strNew = strOld.replaceFirst("l", "c");
        System.out.println("Replaced string : " + strNew);
    }
}
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java-replaceFirst().png

6. replaceAll(String regex, String newString)

public class Demo {
    public static void main(String[] args) {
        String strOld = "Hello world";
        System.out.println("Original string : " + strOld);
        String strNew = strOld.replaceFirst("\\s", "");
        System.out.println("Replaced string : " + strNew);
    }
}
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java-replaceAll().png

Okay so that's enough for now.

Thank you for reading.

Please share your thoughts about it and correct me if I'm wrong.

I hope you liked it and found it helpful.

Cover:- Rajat Gour

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My personal blog blog.ritvikdubey.com

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