Java 正则表达式用于检查字符串是否包含字母


以下是用正则表达式在给定输入中匹配字母-

"^[a-zA-Z]*$"

其中,

  • ^ 匹配句子的开头。
  • [a-zA-z] 匹配小写字母和大写字母。
  • * 表示可出现 0 次或多次。
  • & 表示行的结尾。

示例 1

import java.util.Scanner;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class ContainsAlphabetExample {
   public static void main(String[] args) {
      Scanner sc = new Scanner(System.in);
      String names[] = new String[5];
      for(int i=0; i<names.length;i++){
         System.out.println("Enter your name: ");
         names[i] = sc.nextLine();
      }
      //Regular expression to accept English alphabet
      String regex = "^[a-zA-Z]*$";
      //Creating a pattern object
      Pattern pattern = Pattern.compile(regex);
      for (String name : names) {
         //Creating a Matcher object
         Matcher matcher = pattern.matcher(name);
         if(matcher.matches()) {
            System.out.println(name+" is a valid name");
         } else {
            System.out.println(name+" is not a valid name");
         }
      }
   }
}

输出

Enter your name:
krishna
Enter your name:
kasyap
Enter your name:
maruthi#
Enter your name:
Sai_Ram
Enter your name:
Vani.Viswanath
krishna is a valid name
kasyap is a valid name
maruthi# is not a valid name
Sai_Ram is not a valid name
Vani.Viswanath is not a valid name

示例 2

import java.util.Scanner;
public class Just {
   public static void main(String[] args) {
      Scanner sc = new Scanner(System.in);
      System.out.println("Enter your name: ");
      String name = sc.nextLine();
      String regex = "^[a-zA-Z]*$";
      boolean result = name.matches(regex);
      if(result) {
         System.out.println("Given name is valid");
      } else {
         System.out.println("Given name is not valid");
      }
   }
}

输出

Enter your name:
vasu#dev
Given name is not valid

更新于: 2019 年 11 月 21 日

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