Introduction to Programming

indexOf() and substring()

Various int indexOf(String str) and int lastIndexOf(String str) methods return the position of a substring  in a string:

String s = "Introduction";System.out.println(s.indexOf("I"));      //prints: 0System.out.println(s.lastIndexOf("I"));  //prints: 0System.out.println(s.lastIndexOf("i"));  //prints: 9System.out.println(s.indexOf("o"));      //prints: 4System.out.println(s.lastIndexOf("o"));  //prints: 10System.out.println(s.indexOf("tro"));    //prints: 2

Notice that the position count starts from zero.

The method String substring(int beginIndex) returns the rest of the string value, starting from the position (index) passed in as the parameter:

String s = "Introduction";System.out.println(s.substring(1));        //prints: ntroduction ...