Some time you want to check if one String contains another String or
SubString or not e.g. "HelloWorld" contains "Hello" and
"World" SubString.
There are many ways to check SubString in String in Java e.g. contains(), indexOf() or matches() method of java.lang.String class. In
our last article we have seen how
to use matches method of String class with regular expression and In this
article we will see example of contains() and indexOf() method to
check any String or SubString in Java. contains and indexOf method are defined in
java.lang.String class and used to check if String contains a
particular SubString or not, only difference between contains() and indexOf() method is
that, contains is added in Java 5 along with String matches() method
while indexOf() is as old as equals(),
hashCode
and compareTo().
Another difference between contains() and indexOf() method is that contains() return boolean value e.g. true if String contains SubString and false if String doesn't contains SubString but indexOf() return int value, which is actually index of SubString i.e. starting location. indexOf() return -1 if source String does not contain SubString in Java.
Another difference between contains() and indexOf() method is that contains() return boolean value e.g. true if String contains SubString and false if String doesn't contains SubString but indexOf() return int value, which is actually index of SubString i.e. starting location. indexOf() return -1 if source String does not contain SubString in Java.
String contains() and indexOf() Example in Java
Let's see one quick example of how
to use contains() and indexOf() method of Java String class. Here we will
used them to check if String contains a particular SubString or not. In this
Java program we have used String "Hello World" and
checking for word "Hello" and "World" in
this String.
/**
*
* Java program to check String for SubString. This program
* demonstrate two ways to find if One String contains a particular word or not in Java.
* contains() and indexOf() method of String class is used to check SubString
* @author
*/
public class StringContainsExample {
public static void main(String args[]) {
String word = "Hello World";
//indexOf return -1 if String does not contain specified word
if(word.indexOf("World") != -1){
System.err.printf("Yes '%s' contains word 'World' %n" , word);
}else{
System.err.printf("Sorry %s does not contains word 'World' %n " , word);
}
//contains method return boolean true if String contains specified word
if(word.contains("Hello")){
System.err.printf("Great '%s' contains word 'Hello' %n" , word);
}else{
System.err.printf("Sorry %s does not contains word 'Hello' %n" , word);
}
}
}
Output:
Yes 'Hello World' contains word 'World'
Great 'Hello World' contains word 'Hello'
*
* Java program to check String for SubString. This program
* demonstrate two ways to find if One String contains a particular word or not in Java.
* contains() and indexOf() method of String class is used to check SubString
* @author
*/
public class StringContainsExample {
public static void main(String args[]) {
String word = "Hello World";
//indexOf return -1 if String does not contain specified word
if(word.indexOf("World") != -1){
System.err.printf("Yes '%s' contains word 'World' %n" , word);
}else{
System.err.printf("Sorry %s does not contains word 'World' %n " , word);
}
//contains method return boolean true if String contains specified word
if(word.contains("Hello")){
System.err.printf("Great '%s' contains word 'Hello' %n" , word);
}else{
System.err.printf("Sorry %s does not contains word 'Hello' %n" , word);
}
}
}
Output:
Yes 'Hello World' contains word 'World'
Great 'Hello World' contains word 'Hello'
If we re run this Java program again with different input e.g. checking
for Helloo or Woorld SubString which is not in original
String you will receive different output. By the way Another difference between contains() and indexOf() method is
that contains() accept a CharSequence object as
parameter which is a super interface
for String,
StringBuffer and StringBuilder in Java. You can pass either of those object
to contains() method in Java.
These are two quick ways to check
if one String contains other String, Character or Substring or not, which
is very common programming question in Java
interviews, along with how to compare two String in Java or how to split
String in Java. There are lot of changes in Java API from Java 1.5 to Java 1.5
and it's still worth exploring. That's all on String contains() example
and String indexOf() example in Java.
Further Learning
Data Structures and Algorithms: Deep Dive Using Java
Java Fundamentals: The Java Language
Complete Java Masterclass
Other String articles in Java you may find useful:
Excellent....
ReplyDeletehow to check sentence "demonstrate two ways to find if One String contains a particular word or not in Java" contain a word in list {"two", "ways", "one" ,"not"}
ReplyDeleteHow to count the repetition for a particular word in a paragraph?
ReplyDeleteint i,count=0;
Deleteint LengthOfString=word.length();
for(i=0;i<=LengthOfString;i++)
{
if(word.indexOf("World") != -1)
{
count=count+1;
}
}
System.out.println("Total Repetitions are : "+ count)
Nossir.
ReplyDeletethis will be true every time it loops regardless of the number of times the word appears, meaning your count will just equal the length of your string.
How to code if, one word is equal to one index.
ReplyDeleteEx: Hello I am World
Search Word: am
Index: the index should be 2, not 8.
You need to code your own method which will first split the string an create an array of words and then serach. /Alternatively, just split the string and insert into HashMap then serach
Delete