Java中的正則表示式“d”結構
子表示式/元字元“\d”匹配數字。
示例 1
import java.util.regex.Matcher; import java.util.regex.Pattern; public class RegexExample { public static void main( String args[] ) { String regex = "\d 24"; String input = "This is sample text 12 24 56 89 24"; Pattern p = Pattern.compile(regex); Matcher m = p.matcher(input); int count = 0; while(m.find()) { count++; } System.out.println("Number of matches: "+count); } }
輸出
Number of matches: 2
示例 2
以下是一個 Java 程式,該程式從使用者處讀取一個 10 位數。
import java.util.Scanner; import java.util.regex.Matcher; import java.util.regex.Pattern; public class Test { public static void main( String args[] ) { String regex = "\d{10}"; Scanner sc = new Scanner(System.in); System.out.println("Enter your phone number (10 digits): "); String input = sc.nextLine(); //Creating a Pattern object Pattern p = Pattern.compile(regex); //Creating a Matcher object Matcher m = p.matcher(input); if(m.find()) { System.out.println("OK"); } else { System.out.println("Wrong input"); } } }
輸出 1
Enter your phone number (10 digits): 9848022338 OK
輸出 2
Enter your phone number (10 digits): 545 Wrong input
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