从一组字符匹配Java regualr表达式
Java正则表达式中的字符类使用方括号“[]”定义，字符类与指定字符或一组可能的字符中的单个字符匹配。
例如，正则表达式[abc]匹配单个字符a或b或c。同样，“[az]”将字符从a匹配到z。
例子1
import java.util.Scanner;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class RegexExample1 {
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
System.out.println("Enter input text: ");
String input = sc.nextLine();
String regex = "[a-z]";
//创建一个模式对象
Pattern pattern = Pattern.compile(regex);
//匹配字符串中的已编译模式
Matcher matcher = pattern.matcher(input);
int count =0;
while (matcher.find()) {
count++;
}
System.out.println("Number of characters from a to z: "+count);
}
}输出结果
Enter input text: sample data 1234$ Number of characters from a to z: 10
例子2
import java.util.Scanner;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class RegexExample1 {
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
System.out.println("Enter input text: ");
String input = sc.nextLine();
String regex = "[^a-z]";
//创建一个模式对象
Pattern pattern = Pattern.compile(regex);
//匹配字符串中的已编译模式
Matcher matcher = pattern.matcher(input);
int count =0;
while (matcher.find()) {
count++;
}
System.out.println("Number of non-alphabetic characters : "+count);
}
}输出结果
Enter input text: sample data 1234$ Number of non-alphabetic characters : 7