In this program, we will be discussing various methods for replacing multiple characters in String. This can be done using the methods listed below:
- Using String.replace() method
- Using replaceAll() method
- Using replaceFirst() method
Method 1: Using String.replace() method
This method returns a new string resulting from replacing all occurrences of old characters in the string with new characters.
Syntax:
public String replace(char oldch, char newch)
Parameters:
- The old character.
- The new character.
Return Value: It returns a string derived from this string by replacing every occurrence of old character with a new character.
Example
Java
// Java code to demonstrate the// working of replace()public class rep1 {public static void main(String args[]) { // Initialising String String Str = new String("Welcome to neveropen"); // Using replace to replace characters System.out.print("After replacing all o with T : " ); System.out.println(Str.replace('o', 'T')); // Using replace to replace characters System.out.print("After replacing all e with D : " ); System.out.println(Str.replace('e', 'D')); }} |
After replacing all o with T : WelcTme tT geeksfTrgeeks After replacing all e with D : WDlcomD to gDDksforgDDks
Method 2: Using replaceAll() method
This method replaces each substring of the string that matches the given regular expression with the given replace_str.
Syntax:
public String replaceAll(String regex, String replace_str)
Parameters:
- regex: the regular expression to which this string is to be matched.
- replace_str: the string which would replace found expression.
Return Value: This method returns the resulting String.
Example
Java
// Java code to demonstrate the// working of replaceAll()public class rep2 {public static void main(String args[]) { // Initialising String String Str = new String("Welcome to neveropen"); // original string System.out.print("Original String : " ); System.out.println(Str); // Using replaceAll to replace regex with replace_str System.out.print("After replacing regex with replace_str : " ); System.out.println(Str.replaceAll("(.*)geeks(.*)", "AKSHIT SAXENA")); }} |
Original String : Welcome to neveropen After replacing regex with replace_str : AKSHIT SAXENA
Method 3: Using replaceFirst() method
This method replaces the first substring of this string that matches the given regular expression with the given replace_str.
Syntax:
public String replaceFirst(String regex, String replace_str)
Parameters
- regex: The regular expression to which this string is to be matched.
- replace_str: The string which would replace found expression.
Return value: This method returns a resulting string.
Example
Java
// Java code to demonstrate the// working of replaceFirst()public class rep3 {public static void main(String args[]) { // Initialising String String Str = new String("Welcome to neveropen"); // original string System.out.print("Original String : " ); System.out.println(Str); // Using replaceFirst to replace regex with replace_str // Replaces 1st occurrence of geeks with ASTHA System.out.print("After replacing 1st occurrence of regex with replace_str : " ); System.out.println(Str.replaceFirst("geeks", "Akshit")); }} |
Original String : Welcome to neveropen After replacing 1st occurrence of regex with replace_str : Welcome to Akshitforgeeks
