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Usage and examples of Java String split()

Java String (String) Methods

The Java String split() method splits the string at the specified regular expression and returns an array of substrings.

The syntax of the string split() method is:

The string.split(String regex, int limit) method.

split() parameters

The split() method of the string can take two parameters:

  • regex - The string is split at this regular expression (which can be a string)

  • limit (Optional)-Specify the number of generated substrings

If no parameter limit is passed, split() returns all possible substrings.

Split() return value

  • Returns an array of substrings.

Note:If the passed regular expression split() is invalid, the split() method throws a PatternSyntaxException.

Example1Example without limit parameter

//Import the array to convert the array to a string
//Used to print the array
import java.util.Arrays;
class Main {
　　　　public static void main(String[] args) {
　　　　　　　　String vowels = "a::b::c::d:e";
　　　　　　　　//Split the string at "::"
　　　　　　　　//Store the result in a string array
　　　　　　　　String[] result = vowels.split("::");
　　　　　　　　//Convert the array to a string and print
　　　　　　　　System.out.println("result = ",　+　Arrays.toString(result));
　　　　}
}

Output Result

result = [a, b, c, d:e]

Here, we split the string at ::. Since no parameter limit is passed, the returned array contains all substrings.

With limit parameter

  • If the limit parameter is 0 or negative, split() returns an array containing all substrings.

  • If the limit parameter is positive (e.g., n), split() returns the maximum number of substrings n.

Example2With limit parameter

//Import an array, convert the array to a string
import java.util.Arrays;
class Main {
　　　　public static void main(String[] args) {
　　　　　　　　String vowels = "a:bc:de:fg:h";
　　　　　　　　//　Split the string at ":"
　　　　　　　　//　limit =　-2; The array contains all substrings
　　　　　　　　String[] result = vowels.split(":",　-2);
　　　　　　　　System.out.println("returns when limit is　-2　returns = "　+　Arrays.toString(result));
　　　　　　　　//　limit = 0; The array contains all substrings
　　　　　　　　result = vowels.split(":", 0);
　　　　　　　　System.out.println("returns when limit is 0 = "　+　Arrays.toString(result));
　　　　　　　　//　limit =　2; The array can contain at most2number of substrings
　　　　　　　　result = vowels.split(":",　2);
　　　　　　　　System.out.println("returns when limit is　2　returns = "　+　Arrays.toString(result));
　　　　　　　　//　limit =　4; The array can contain at most4number of substrings
　　　　　　　　result = vowels.split(":",　4);
　　　　　　　　System.out.println("returns when limit is　4　returns = "　+　Arrays.toString(result));
　　　　　　　　//　limit =　10; The array can contain at most10number of substrings
　　　　　　　　result = vowels.split(":",　10);
　　　　　　　　System.out.println("returns when limit is　10　returns = "　+　Arrays.toString(result));
　　　　}
}

Output Result

returns when limit is　-2　returns = [a, bc, de, fg, h]
returns when limit is 0 = [a, bc, de, fg, h]
returns when limit is　2　returns = [a, bc:de:fg:h]
returns when limit is　4　returns = [a, bc:de:fg:h]
returns when limit is　10　returns = [a, bc, de, fg, h]

Note: split()The method takes a regular expression as the first parameter. If special characters, such as \, |, ^, are needed,*、+ such as, you need to escape these characters. For example, we need to use \\+ to split +.

Example3: split() splits the string at+at character position

//Import the array to convert the array to a string
//Used to print the array
import java.util.Arrays;
class Main {
　　　　public static void main(String[] args) {
　　　　　　　　String vowels = "a+e+f";
　　　　　　　　//Split the string at+
　　　　　　　　String[] result = vowels.split("\\+");
　　　　　　　　//Convert the array to a string and print
　　　　　　　　System.out.println("result = ",　+　Arrays.toString(result));
　　　　}
}

Output Result

result = [a, e, f]

Here, to be+split the string at the position, we used \\+. This is because+is a special character (with special meaning in regular expressions).

Java String (String) Methods

Java Method OverloadingComprehensive Java String Methods