Java String Split() Method – How To Split A String In Java

This Tutorial will Explain how to Split a String using Java String Split() Method. You will learn How and Where to use this Method to Manipulate the String:

We will explore the description of the Java Split() method and will learn to use this method with the help of programming examples.

You will find the concepts easy to understand as sufficient programming examples are provided with details in the comment section of the programs or as a separate explanation.

=> Watch Out The Simple Java Training Series Here.

Java String Split method

Upon going through this tutorial, you will be able to understand the different forms of the String Split() Java method and you will be comfortable in using it in your programs.

Introduction To Java String Split() Method

As the name suggests, a Java String Split() method is used to decompose or split the invoking Java String into parts and return the Array. Each part or item of an Array is delimited by the delimiters(“”, “ ”, \\) or regular expression that we have passed.

The syntax of the Java String Split() method is given as:

String[ ] split(String regExp)

The return type of Split is an Array of type Strings.

Let’s consider the following scenarios.

Various Usage Scenarios

Scenario 1: In this scenario, we are initializing a Java String variable consisting of different words separated by space, and then we will perform the Java String Split() method and observe the output.

Using the Java Split() method, we will successfully print each of the words without including the space.

Explanation: Here, we have initialized a Java String variable and using the regular expression “\\s”, we have split the String wherever whitespace occurred.

Then, we have printed the result using a For-each loop.

package codes;

public class StringSplit {

	public static void main(String[] args) {
		String str = "This is an example";
		String[] splits = str.split("\\s");
		//This regEx splits the String on the WhiteSpaces 
		for(String splits2: splits) {
			System.out.println(splits2);
		}

	}

}

Output:

Scenario 1 - output

Scenario 2: In this scenario, we are initializing a Java String variable, and then using a substring of that main String variable, we will try to split or decompose the main String variable using the String Split() method.

Explanation: Here, we have initialized a String variable str which is the main String and tried to split the String variable excluding the substring “Engineer”. Finally, we have used a For-each loop to print the String. You can iterate the element using the loop of your choice.

package codes;

public class StringSplit {

	public static void main(String[] args) {
		String str = "SoftwareEngineerTestingEngineerHelp";
		String[] splits = str.split("Engineer");
		
		for(String splits2: splits) {
			System.out.println(splits2);
		}

	}

}

Output:

Scenario 2 - output

Scenario 3: In this scenario, we will take a String variable (single word), and then we will try to split the String using the character of the String.

Explanation: Here, we have initialized a String variable str that contains a single word. Then we have performed the Split() method using a single character of the main String. Finally, we have printed the result using a simple for loop.

package codes;

public class StringSplit {

	public static void main(String[] args) {
		String str = "scare";
		String[] splits = str.split("e");
		//This regEx splits the String on ‘e’
		for(int i=0; i<splits.length;i++) {
			System.out.print(splits[i]);
		}

	}
}

Output:

Scenario 3 - output

Java Split RegEx With Length

This is another variation or you can call it the option that is available in the Java Split() method. In this option, everything else is the same except that we will provide an integer that determines the number of decompositions or pieces the String will have.

The syntax is given as:

String[ ] split(String regExp, int num)

Values of num:

#1) If num has a positive non-zero value. In this case, the last substring in the result will contain the remaining part of the String.

For Example: If num is 2 then it will split into two words. Likewise, if num is 1 then it will not be split and will print the String in a single word. This does not consider the size of the String.

#2) If num is negative or zero then the invoking String is fully split or decomposed.

Complete Programming Example

In this example, we will initialize a String, and then we will try giving different values of num and will observe the output for each of the values entered. This will give you a clear picture of how a Java Split RegEx with length works.

package codes;

public class StringSplit {

	public static void main(String[] args) {
		
		String str="Split Tutorial by Saket Saurav";  
		
		System.out.println("This is for num = 0:");  
		for(String splits:str.split("\\s",0)) {  
			System.out.println(splits);  
		}
		System.out.println();

		System.out.println("This is for num = 1:");  
		for(String splits:str.split("\\s",1)) {  
			System.out.println(splits);  
		}
		System.out.println();
		
		System.out.println("This is for num = 2:");  
		for(String splits:str.split("\\s",2)) {  
			System.out.println(splits);  
		}
		System.out.println();
		
		System.out.println("This is for num = -1:");
		for(String splits:str.split("\\s",-1)) {
			System.out.println(splits);
		}
		System.out.println();
		
		System.out.println("This is for num = -2:");
		for(String splits:str.split("\\s",-2)) {
			System.out.println(splits);
		}
		System.out.println();
		
		System.out.println("This is for num = 5:");
		for(String splits:str.split("\\s",5)) {
			System.out.println(splits);
		}
		System.out.println();
	}

}

Output:

Programming Example - Output

Explanation:

This program covers all the aspects of the Java Split RegEx with length. Here, we have initialized a Java String variable consisting of five words. Then we have performed the Java Split() method for six different scenarios.

The explanation of each scenario is given below.

  • Case 1 (num = 0): This will print the entire String as it does not depend on the number of words that a String variable has. Thus the output will be all the five words that we have taken as a String variable.
  • Case 2 (num = 1): This will also print the entire String but in a single line as num is specified with the value as 1.
  • Case 3 (num = 2): This will print the String but in two different lines. The first line will be the first word that comes in a String and the remaining will be printed in the second line.
  • Case 4 (num = -1): As we have already discussed, all the zeros and negative num values will result in the complete decomposition, thus it will also print just like Case 1.
  • Case 5 (num = -2): Same as Case 4, it is also a negative value.
  • Case 6 (num = 5): As the String has only five words, it will print all the five words in a new line.

Frequently Asked Questions

Q #1) What does String Split() do in Java?

Answer: Java String Split() decomposes or splits the invoking string into parts where each part is delimited by the BRE (Basic Regular Expression) that we pass in the regEx. It returns an array.

Q #2) What is S in Java?

Answer: The String “\\s” is a basic regular expression (BRE) in Java which means whitespaces.

package codes;

public class StringSplit {

	public static void main(String[] args) {
		
		String str="Basic Regular Expression";
		String[] split = str.split("\\s");
		for(int i=0; i<split.length; i++) {
			System.out.print(split[i]);
		}
		
		
	}

}

Output:

S in Java

Q #3) What is Regex in Java?

Answer: Regular Expression is the full form of regex which is an API. This API is used to manipulate a String in Java. It is a part of Java.util package. These regular expressions are very handy as it provides various options to perform any kind of operation on a given String.

For Example, Email Validations, Performing a search operation, Removing spaces in between a large String, etc.

Q #4) How to split a string in Java without delimiter or How to split each character in Java?

Answer: You just have to pass (“”) in the regEx section of the Java Split() method. This will split the entire String into individual characters.

package codes;

public class StringSplit {

	public static void main(String[] args) {
		
		for(String str : "Federer".split(""))
		    System.out.println(str);
		
	}

}

Output:

split a string in Java without delimiter - output

Q #5) How to split a String by Space?

Answer: Here, you have to pass (” “) in the regEx section of the Java Split() method. This will split a String by Space.

package codes;

public class StringSplit {

	public static void main(String[] args) {
		
		for(String str : "Software Engineer".split(" "))
		    System.out.print(str);
	}

}

Output:

split a String by Space - output

Conclusion

In this tutorial, we have understood the Java String Split() method in detail. The basic functionality, usage, and options (regex and regex with length) were explained in detail along with simple programming examples with the explanation of the programs wherever required.

For better understanding, this tutorial was explained with the help of different scenarios. Each scenario/case has its importance as it shows the application areas of the String Split() method. The inclusion of the frequently asked questions would have helped you in understanding the concept even better.

=> Visit Here To Learn Java From Scratch.