Java String indexOf() method
Java String indexOf() method returns index of a given character or substring present in a String.
Methods Description
int indexOf(int ch)
| It returns index position for the given char value. |
int indexOf(int ch, int fromIndex)
| It returns index position for the given char value and from index. |
int indexOf(String substring)
| It returns index position for the given substring. |
int indexOf(String substring, int fromIndex)
| It returns index position for the given substring and from index. |
Parameters:
ch: a single character
fromIndex: index position from where index of the char value or substring is returned
substring: substring to be searched in this string
Return:
It returns index of the character within a String
Java String IndexOf() method Example 1
public class JavaStringIndexOfEx1{ public static void main(String args[]){ String s1="welcome to tutorial and example"; //passing substring int index1=s1.indexOf("to"); int index2=s1.indexOf("and"); System.out.println(index1+" "+index2); //passing substring with from index int index3=s1.indexOf("to",9); int index4=s1.indexOf("to",5); System.out.println(index3); System.out.println(index4); //passing char value int index5=s1.indexOf('a'); int index6=s1.indexOf('z'); System.out.println(index5); System.out.println(index6); } }
Output:
8 20 13 8 17 -1
Java String indexOf(String substring) Method Example 2
public class JavaStringIndexOfEx2 { public static void main(String[] args) { String s1 = "India is a great "; String s2 = s1.concat("Country in the world"); // Passing Substring int index = s2.indexOf("the"); //Returns the index of this substring int index2 = s1.indexOf("the"); int index3 = s2.indexOf("a"); int index4 = s2.indexOf(" "); System.out.println("index of substring "+index); System.out.println("index of substring "+index2); System.out.println("index of substring "+index3); System.out.println("index of substring "+index4); } }
Output:
index of substring 28 index of substring -1 index of substring 4 index of substring 5
Java String indexOf(String substring, int fromIndex) Method Example 3
public class JavaStringIndexOfEx3 { public static void main(String[] args) { String s1 = "India is a great "; String s2 = s1.concat("Country in the world"); // Passing substring and index int index = s2.indexOf("the", 10); //Returns the index of this substring int index2 = s1.indexOf("the", 5); int index3 = s2.indexOf("a", 25); //Passing substring int index4 = s2.indexOf(" "); System.out.println("index of substring "+index);//Returns the index of this substring System.out.println("index of substring "+index2); System.out.println("index of substring "+index3);// It returns -1 if substring does not found System.out.println("index of substring "+index4); } }
Output:
index of substring 28 index of substring -1 index of substring -1 index of substring 5