coderz.py

The methods listed below are some of the most frequently used String class methods in Java.

charAt() method:

The charAt() function in a string returns the character at the specified index.

class HelloWorld {
    public static void main(String[] args) {
        String myStr = "Hello";
        char result = myStr.charAt(0);
        System.out.println(result);
    }
}

Output:

H

equalsIgnoreCase() method:

equalsIgnoreCase() checks for equality between two Strings while ignoring their case.

        class HelloWorld {
    public static void main(String[] args) {
        String myStr = "Hello",str="Coder";
        boolean result = myStr.equalsIgnoreCase(str);
        System.out.println(result);
    }
}

Output:

false

indexOf() method:

The index of the first occurrence of a substring or a character is returned by the indexOf() method.

 class HelloWorld {
    public static void main(String[] args) {
       String myStr = "Hello planet earth, you are a great planet.";
    System.out.println(myStr.indexOf("e", 5));
    }
}

Output:

10

length() method:

The length() function of a String returns the number of characters in it.

 class HelloWorld {
    public static void main(String[] args) {
       String myStr = "Hello planet earth, you are a great planet.";
    System.out.println(myStr.length());
    }
}

Output:

43

replace() method:

The replace() method in a string replaces all occurrences of a character with a new character.

public class Demo {
    public static void main(String[] args) {   
        String str = "coderzpy";
        System.out.println(str.replace('c','C'));
    }
}

Output:

Coderzpy

substring() method:

The substring() method returns a part of the string.

public class Demo {
    public static void main(String[] args) {
        String str = "ABCDEFGHIJKLMNO";
        System.out.println(str.substring(4));
        System.out.println(str.substring(4,7));        
    }
}

Output:

EFGHIJKLMNO
EFG

valueOf() method:

String class uses an overloaded version of valueOf() method for all primitive data types and for type Object.

public class Demo {
    public static void main(String[] args) {
         int num = 115;
         String s1 = String.valueOf(num);    //converting int to String
         s1+= "hello";
         System.out.println(s1);
         System.out.println("type of num : "+s1.getClass().getName());   
    }
}

Output:

115hello
type of num : java.lang.String

trim() method:

This method returns a string that has been stripped of any leading and trailing whitespaces.

public class Demo {
    public static void main(String[] args) {
        String str = "   hello coderzpy  ";
        System.out.println(str.trim());   
    }
}

Output:

hello coderzpy

endsWith() method:

the endsWith() method is used to determine whether the string ends with the specified suffix. If the suffix matches the string, it returns true; otherwise, it returns false.

public class Demo {
    public static void main(String[] args) {
        String a="Hello welcome to Coderzpy.com";  
        System.out.println(a.endsWith("m"));  
        System.out.println(a.endsWith("com"));       
    }
}
    

Output:

true
true

Note: also read about the String class methods in Java

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