Posix字符类p {Digit} Java正则表达式

Posix character classes \p{Digit} Java regex

此类匹配从10到9的十进制数字。

例子1

现场演示

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import java.util.Scanner;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class DigitsExample {
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{Digit}]";
//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 digits:"+count);
}
}

输出1

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Enter a string
sample text 22 37 48 84
Number of digits: 8

输出2

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Enter a string
Welcome to tutorilspoint
Number of digits: 0

例子2

现场演示

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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{Digit}+$";
//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 only digits:");
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());
}
}
}
}

输出量

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Enter 5 input strings:
hello
1234
243test
##$$@
222356
Strings with only digits:
1234
222356