Posix文字クラス\p{Space}Java正規表現。

このクラスは空白文字と一致します。つまり、\ t、\ n、\ x、0B、\ f、\r。

例1

import java.util.Scanner;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class SpaceCharacters {
   public static void main(String args[]) {
      //Reading String from user
      System.out.println("Enter a string");
      Scanner sc = new Scanner(System.in);
      String input = sc.nextLine();
      //Regular expression
      String regex = "[\\p{Space}]";
      //Compiling the regular expression
      Pattern pattern = Pattern.compile(regex);
      //Retrieving the matcher object
      Matcher matcher = pattern.matcher(input);
      int count = 0;
      while(matcher.find()) {
         count++;
      }
      System.out.println("Number of space characters: "+count);
   }
}

出力

Enter a string
space tab test
Number of space characters: 2

例2

import java.util.Scanner;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class Example {
   public static void main( String args[] ) {
      //Regular expression to match lower case letters
      String regex = "^.*\\p{Space}.*$";
      //Getting the input data
      Scanner sc = new Scanner(System.in);
      System.out.println("Enter 5 input strings: ");
      String input[] = new String[5];
      for (int i=0; i<5; i++) {
         input[i] = sc.nextLine();
      }
      //Creating a Pattern object
      Pattern p = Pattern.compile(regex);
      System.out.println("Strings with spaces: ");
      for(int i=0; i<5;i++) {
         //Creating a Matcher object
         Matcher m = p.matcher(input[i]);
         if(m.matches()) {
            System.out.println(m.group());
         }
      }
   }
}

出力

Enter 5 input strings:
sample data
hello
welcome to tutorialspoint
12345
ab bc cd da
Strings with spaces:
sample data
welcome to tutorialspoint
ab bc cd da