字符类: 范围 - Java 正则表达式
Java 正则表达式中的字符类使用方括号 "[ ]" 定义,此子表达式匹配指定字符中或一组可能字符中的单个字符。例如,正则表达式 [abc] 匹配单个字符 a 或 b 或 c。
字符类的范围变体允许你使用字符范围,即表达式 [a-z] 匹配字母 a 到 z 之间的单个字符,而表达式 [^A-Z] 匹配的字符不是大写字母。
示例 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]";
//Creating a pattern object
Pattern pattern = Pattern.compile(regex);
//Matching the compiled pattern in the String
Matcher matcher = pattern.matcher(input);
int count =0;
while (matcher.find()) {
count++;
}
System.out.println("Number characters from the range (a-z): "+count);
}
}输出
Enter input text: sample data 5423 #@ %*& Number characters from the range (a-z): 10
示例 2
import java.util.Scanner;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class RegexExample3 {
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]";
//Creating a pattern object
Pattern pattern = Pattern.compile(regex);
//Matching the compiled pattern in the String
Matcher matcher = pattern.matcher(input);
int count =0;
if (matcher.find()) {
System.out.println("match occurred");
} else {
System.out.println("match not occurred");
}
}
}输出 1
Enter input text: sample data match occurred
输出 2
Enter input text: SAMPLEDATA match not occurred
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