在 Java 正则表达式中说明元字符“B”。
子表达式/元字符“\B”匹配非单词边界。
示例 1
import java.util.Scanner; import java.util.regex.Matcher; import java.util.regex.Pattern; public class RegexExample { public static void main( String args[] ) { String regex = "\Bcause"; Scanner sc = new Scanner(System.in); System.out.println("Enter a string: "); String input = sc.nextLine(); 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
Enter a string: A sentence doesn't end with because because, because is a conjunction Number of matches: 3
示例 2
import java.util.Scanner; import java.util.regex.Matcher; import java.util.regex.Pattern; public class Example { public static void main( String args[] ) { System.out.println("Enter input string: "); Scanner sc = new Scanner(System.in); String input = sc.nextLine(); String regex = "\B"; //Compiling the regular expression Pattern pattern = Pattern.compile(regex); //Retrieving the matcher object Matcher matcher = pattern.matcher(input); int count =0; System.out.println("Non-word boundaries: "); while(matcher.find()) { count ++; } System.out.println(count); } }
输出
Enter input string: Hello how are you welcome to Tutorialspoint Non-word boundaries: 30
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