Splitting strings is a very frequent operation performed when coding. There are many ways to split a string in Java but the most common way is using the String split() method. This article is focused on how to split strings using the split method in Java.
Listed below are the topics covered in this article:
- Split Method in Java
- Using a split() method without the limit parameter
- Using a split() method with the limit parameter
Split Method in Java
The String class in Java offers a split() method that can be used to split a string into an array of String objects based on delimiters that match a regular expression. For instance, given the following string:
String s = "Welcome, To, Edureka!";
You can split the string into sub-strings using the following piece of code:
String[] result = s.split(",");More accurately, that expression will break the string into sub-strings wherever the sub-strings are separated by delimiter characters. In the above example, the input string ‘Welcome, To, Edureka’, is split into three string objects, namely:
There are two variants of a split() method in Java. Let’s discuss each of them.
Using a split() method without limit parameter
This variant of the split() method accepts a regular expression as a parameter and breaks the given string based on the regular expression regex. Here the default limit is 0. Listed below are the syntax, parameter, return value, exceptions thrown and a lot of example programs demonstrating the concept.
Syntax: public String[] split(String regex)
Parameter: regex (a delimiting regular expression)
Return Value: an array of String objects
Exception: PatternSyntaxException, if the provided regular expression’s syntax is invalid
Example1: Calling a split() method on String Object – Splitting by a comma
package MyPackage;
public class Method1 {
public static void main(String args[])
{
String str = "We're,Ridiculously,Committed!";
String[] arrOfStr = str.split(",");
System.out.println("Number of substrings: "+arrOfStr.length);
for(int i=0; i< arrOfStr.length; i++)
{
System.out.println("str["+i+"] : "+arrOfStr[i]);
}
}
} Number of substrings: 3 str[0] : We're str[1] : Ridiculously str[2] : Committed!
Example2: Calling a split() method on String Object – Splitting by a whitespace
package MyPackage;
public class Method2 {
public static void main(String args[])
{
String str = "We're Ridiculously Committed! Welcome";
String[] arrOfStr = str.split(" ");
System.out.println("Number of substrings: "+arrOfStr.length);
for(int i=0; i< arrOfStr.length; i++)
{
System.out.println("str["+i+"] : "+arrOfStr[i]);
}
}
} Number of substrings: 4 str[0] : We're str[1] : Ridiculously str[2] : Committed! str[3] : Welcome
Example3: Calling a split() method on String Object – Splitting by a dot
package MyPackage;
public class Method3 {
public static void main(String args[])
{
String str = "We're.Ridiculously.Committed.Welcome";
String[] arrOfStr = str.split(".");
System.out.println("Number of substrings: "+arrOfStr.length);
for(int i=0; i< arrOfStr.length; i++)
{
System.out.println("str["+i+"] : "+arrOfStr[i]);
}
}
} Number of substrings: 4 str[0] : We're str[1] : Ridiculously str[2] : Committed str[3] : Welcome
Example4: Calling a split() method on String Object – Splitting by using a letter
package MyPackage;
public class Method4 {
public static void main(String args[])
{
String str = "We're Ridiculously Committed! Welcome";
String[] arrOfStr = str.split("W");
System.out.println("Number of substrings: "+arrOfStr.length);
for(int i=0; i< arrOfStr.length; i++)
{
System.out.println("str["+i+"] : "+arrOfStr[i]);
}
}
} Number of substrings: 3 str[0] : str[1] : e're Ridiculously Committed! str[2] : elcome
Example5: Calling a split() method on String Object – Splitting by multiple delimiters
package MyPackage;
public class Method5 {
public static void main(String args[])
{
String str = "We're, Ridiculously Committed! Welcome to Eduerka.Hello";
String[] arrOfStr = str.split("[, .!]+");
System.out.println("Number of substrings: "+arrOfStr.length);
for(int i=0; i< arrOfStr.length; i++)
{
System.out.println("str["+i+"] : "+arrOfStr[i]);
}
}
} Number of substrings: 7 str[0] : We're str[1] : Ridiculously str[2] : Committed str[3] : Welcome str[4] : to str[5] : Eduerka str[6] : Hello
Well, it’s simple enough, right? But what if you require only the first ‘n’ elements after the split operation but want the rest of the string to remain as it is? For that, we have another variant of the split() method.
Using a split() method with the limit parameter
This variant of the split() method is used when we want the string to be split into a limited number of strings. The only difference between this variant of split() method and other one is that it limits the number of strings returned after split up. The limit can be given as an input parameter to the split() method. The limit parameter controls the number of times the pattern is applied and hence affects the length of the resulting array.
Listed below are the syntax, parameter, return value, exceptions thrown and a lot of example programs demonstrating the concept.
Syntax: public String[] split(String regex, int limit)
Parameter:
- regex – a delimiting regular expression
- limit – the resulting threshold
The limit can have 3 values, which are:
- limit > 0: If the limit is positive, then the pattern will be applied at most limit-1 times. The resulting array’s length will be no greater than n, and the array’s last entry will contain all input beyond the last matched delimiter.
- limit < 0: If the limit is positive, then the pattern will be applied as many times as possible and the resulting array can have any length.
- limit = 0: If the limit is equal to 0, the pattern will be applied as many times as possible, the resulting array can have any length but the trailing empty strings will be discarded.
Return Value: an array of String objects computed by splitting the given string according to limit parameter
Exception: PatternSyntaxException, if the provided regular expression’s syntax is invalid
Example: Calling a split() method on String Object with the limit parameter
package MyPackage;
public class SplitMethod {
public static void main(String args[])
{
String str = "468-567-7388";
String[] arrOfStr1 = str.split("8",2);
System.out.println("Output when limit is +ve");
System.out.println("Number of substrings: "+arrOfStr1.length);
for(int i=0; i<arrOfStr1.length; i++)
{
System.out.println("str["+i+"] : "+arrOfStr1[i]);
}
String[] arrOfStr2 = str.split("8",-3);
System.out.println("nOutput when limit is -ve");
System.out.println("Number of substrings: "+arrOfStr2.length);
for(int i=0; i<arrOfStr2.length; i++)
{
System.out.println("str["+i+"] : "+arrOfStr2[i]);
}
String[] arrOfStr3 = str.split("8",0);
System.out.println("nOutput when limit is 0");
System.out.println("Number of substrings: "+arrOfStr3.length);
for(int i=0; i<arrOfStr3.length; i++)
{
System.out.println("str["+i+"] : "+arrOfStr3[i]);
}
}
} Output:
Output when limit is +ve Number of substrings: 2 str[0] : 46 str[1] : -567-7388 Output when limit is -ve Number of substrings: 4 str[0] : 46 str[1] : -567-73 str[2] : str[3] : Output when limit is 0 Number of substrings: 2 str[0] : 46 str[1] : -567-73
The above program demonstrates how the split() method works when the limit parameter is specified. As you see from the output:
- When the limit is 2, the number of substrings in the resulting array is two
- When the limit is -3, the input string is split into 4 substrings, including the trailing spaces
- When the limit is 0, the input string is split into 2 substrings because trailing spaces are excluded
This brings us to the end of this ‘Split Method in Java’ article. I have covered one of the fundamental topics of Java, on how to split strings using the split() method in Java. Hope you are clear with all that has been shared with you in this article.
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