Java 中的正则表达式“W”元字符


子表达式/元字符“\W”匹配非单词字符。

示例一

import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class RegexExample {
   public static void main(String args[]) {
      String regex = "\W!";
      String input = "Hello how are you welcome to Tutorialspoint !";
      Pattern p = Pattern.compile(regex);
      Matcher m = p.matcher(input);
      int count = 0;
      while(m.find()) {
         count++;
      }
      System.out.println("Number of matches: "+count);
   }
}

输出

Number of matches: 1

示例二

以下示例读取 5 个字符串值,并打印那些包含非单词字符的值:

import java.util.Scanner;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class Example {
   public static void main( String args[] ) {
      String regex = "\W.*$";
      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 that contain non-word characters: ");
      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());
         }
      }
   }
}

输出

Enter 5 input strings:
$hello
sample
test1
test2
#$&*
Strings that contain non-word characters:
$hello
#$&*

更新于: 2019-11-19

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