how to get substring code example

Example 1: substring javascript

var str = "Hello world!";
var res = str.substring(1, 4); //ell

Example 2: how to do substring java

class Main {
  public static void main (String[] args) {
    
    String str = "Hello World!";
    
    String firstWord = str.substring(0, 5);
    //two parameters are start and end index: (inclusive, non-inclusive)
    
    String secondWord = str.substring(6, 11);
    
    //firstWord has string "Hello"
    //secondWord has string "World"
  }
}

Example 3: str.substring if 2 letters

public String firstTwo(String str) {
    return str.length() < 2 ? str : str.substring(0, 2);
}