Posix字符类\ p {Digit} Java正则表达式
此类匹配从0到9的十进制数字。
例子1
import java.util.Scanner;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class DigitsExample {
public static void main(String args[]) {
//从用户读取字符串
System.out.println("Enter a string");
Scanner sc = new Scanner(System.in);
String input = sc.nextLine();
//正则表达式
String regex = "[\\p{Digit}]";
//Compiling the 正则表达式
Pattern pattern = Pattern.compile(regex);
//检索匹配器对象
Matcher matcher = pattern.matcher(input);
int count = 0;
while(matcher.find()) {
count++;
}
System.out.println("Number of digits: "+count);
}
}输出1
Enter a string sample text 22 37 48 84 Number of digits: 8
输出2
Enter a string Welcome to tutorilspoint Number of digits: 0
例子2
import java.util.Scanner;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class Example {
public static void main( String args[] ) {
//正则表达式 to match lower case letters
String regex = "^\\p{Digit}+$";
//获取输入数据
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();
}
//创建一个Pattern对象
Pattern p = Pattern.compile(regex);
System.out.println("Strings with only digits: ");
for(int i=0; i<5;i++) {
//创建一个Matcher对象
Matcher m = p.matcher(input[i]);
if(m.matches()) {
System.out.println(m.group());
}
}
}
}输出结果
Enter 5 input strings: hello 1234 243test ##$$@ 222356 Strings with only digits: 1234 222356