解释Java正则表达式中的子表达式“ [...]”
子表达式“[...]”匹配括号中指定的任何单个字符。
例子1
import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class SpecifiedCharacters {
public static void main( String args[] ) {
String regex = "[hwt]";
String input = "Hi how are you welcome to Nhooo";
Pattern p = Pattern.compile(regex);
Matcher m = p.matcher(input);
int count = 0;
while(m.find()) {
count++;
}
System.out.println("Number of matches: "+count);
}
}输出结果
Number of matches: 6
例子2
以下Java程序从用户那里接收5个字符串，并打印包含元音字母的字符串/单词。
import java.util.Scanner;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class RegexExample {
public static void main( String args[] ) {
String regex = "^.*[aeiou].*$";
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 that contain vowel letters: ");
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 sample rhythm cry gym strings that contain vowel letters: hello sample