Java String substring() usage and example

Java String (String) Methods

Java String substring() method extracts a substring from the string and returns it.

The syntax of substring() method is:

string.substring(int startIndex, int endIndex)

substring() parameters

The substring() method has two parameters.

• startIndex - Start index

• endIndex (Optional)-End index

The return value of substring()

The substring() method returns a substring from the given string.

• The substring exists with the character at startIndex and extends to the index endIndex - 1of the characters.

• If endIndex is not passed, the substring exists with the character at the specified index and extends to the end of the string.

Note:If startIndex or endIndex is negative or greater than the length of the string, an error will occur. An error will also occur if startIndex is greater than endIndex.

Example1: Java substring() without ending index

class Main {
　　　　public static void main(String[] args) {
　　　　　　　　String str1　= "program";
　　　　　　　　//from the first character to the end
　　　　　　　　System.out.println(str1.substring(0));　　//　program
　　　　　　　　//from the fourth character to the end
　　　　　　　　System.out.println(str1.substring(3));　　//　gram
　　　　}
}

Example2: Java substring() with ending index

class Main {
　　　　public static void main(String[] args) {
　　　　　　　　String str1　= "program";
　　　　　　　　//from the first character to the seventh character
　　　　　　　　System.out.println(str1.substring(0,　7));　　//　program
　　　　　　　　//from1to5character
　　　　　　　　System.out.println(str1.substring(0,　5));　　//　progr
　　　　　　　　//from4to5character
　　　　　　　　System.out.println(str1.substring(3,　5));　　//　gr
　　　　}
}

If you need to find the index of the first occurrence of a specified substring in a given string, useJava String indexOf() Method.

Java String (String) Methods