Java Character isLetterOrDigit() 方法

2024年11月6日 | 阅读 6 分钟

Character 类的 isLetterOrDigit(char ch) 方法用于确定给定的（或指定的）字符是否是字母或数字。

如果给定的字符满足 Character.isLetter(char ch) 或 Character.isDigit(char ch) 方法返回 true，则该字符被认为是字母或数字。

注意：上述方法不能用于处理增补字符。为了处理增补字符，我们可以使用 isLetterOrDigit(int) 方法。

语法

参数

上述方法只需要一个参数

a.) 需要测试的字符。

返回值

isLetterOrDigit(char ch) 方法返回一个布尔值，即如果给定的（或指定的）字符是字母或数字，则返回 true。否则，该方法返回 false。

示例 1

public class JavaCharacterisLetterOrDigitExample1 {
   public static void main(String[] args) {
      // Create four char primitives ch1, ch2, ch3 and ch4.
      char ch1;
      char ch2;
      char ch3;
      char ch4;
      // Assign the values to ch1, ch2, ch3 and ch4.
      ch1 = 'A';
      ch2 = '1';
      ch3 = 'U';
      ch4 = '2';
      // Create four boolean primitives b1, b2, b3 and b4.
      boolean b1 = Character.isLetterOrDigit(ch1);
      boolean b2 = Character.isLetterOrDigit(ch2);
      boolean b3 = Character.isLetterOrDigit(ch3);
      boolean b4 = Character.isLetterOrDigit(ch4);
      String str1 = "The first character '"+ ch1+ "' is a letter or digit: " + b1;
      String str2 = "The second character '"+ch2+"' is a letter or digit: " + b2;
      String str3 = "The third character '"+ch3+ "' is a letter or digit: " + b3;
      String str4 = "The fourth character '"+ch4+ "' is a letter or digit: " + b4;
      // Print the values of b1, b2, b3 and b4;
      System.out.println( str1 );
      System.out.println( str2 );
      System.out.println( str3 );
      System.out.println( str4 );
   }
}

输出

The first character 'A' is a letter or digit: true
The second character '1' is a letter or digit: true
The third character 'U' is a letter or digit: true
The fourth character '2' is a letter or digit: true

示例 2

public class JavaCharacterisLetterOrDigitExample2 {
   public static void main(String[] args) {
      // Create four char primitives ch1, ch2, ch3 and ch4.
      char ch1;
      char ch2;
      char ch3;
      char ch4;
      // Assign the values to ch1, ch2, ch3 and ch4.
      ch1 = 'A';
      ch2 = '1';
      ch3 = '*';
      ch4 = '$';
      // Create four boolean primitives b1, b2, b3 and b4.
      boolean b1 = Character.isLetterOrDigit(ch1);
      boolean b2 = Character.isLetterOrDigit(ch2);
      boolean b3 = Character.isLetterOrDigit(ch3);
      boolean b4 = Character.isLetterOrDigit(ch4);
      String str1 = "The first character '"+ ch1+ "' is a letter or digit: " + b1;
      String str2 = "The second character '"+ch2+"' is a letter or digit: " + b2;
      String str3 = "The third character '"+ch3+ "' is a letter or digit: " + b3;
      String str4 = "The fourth character '"+ch4+ "' is a letter or digit: " + b4;
      // Printr the values of b1, b2, b3 and b4.
      System.out.println( str1 );
      System.out.println( str2 );
      System.out.println( str3 );
      System.out.println( str4 );
   }
}

输出

The first character 'A' is a letter or digit: true
The second character '1' is a letter or digit: true
The third character '*' is a letter or digit: false
The fourth character '$' is a letter or digit: false

示例 3

import java.util.Scanner;
public class JavaCharacterisLetterOrDigitExample3 {
   public static void main(String[] args) {
    // Ask for user input
       System.out.print("Enter the first input:");
    // Use the Scanner class to get the user input
       Scanner s1 = new Scanner(System.in);
    // Gets the user input
       char[] value1 = s1.nextLine().toCharArray();
    // Check whether the user input is a letter or not.
       for (char ch1 : value1) {
   boolean result1 = Character.isLetterOrDigit(ch1);
    // print the result
       if(result1){
System.out.println("The character '" + ch1 + "' is a letter or digit. ");				
                  }
     else{
System.out.println("The character '" + ch1 + "' is neither a letter nor a digit.");
           }		
       System.out.print("Enter the second input:");
       Scanner s2 = new Scanner(System.in);
       char[] value2 = s2.nextLine().toCharArray();
       for (char ch2 : value2) {
      boolean result2 = Character.isLetterOrDigit(ch2);
      if(result2){
System.out.println("The character '" + ch2 + "' is a letter or digit. ");				
                }
      else{
System.out.println("The character '" + ch2 + "' is neither a letter nor a digit.");
        }		
      System.out.print("Enter the third input:");
       Scanner s3 = new Scanner(System.in);
       char[] value3 = s3.nextLine().toCharArray();
       for (char ch3 : value3) {
      boolean result3 = Character.isLetterOrDigit(ch3);
      if(result2){
System.out.println("The character '" + ch3 + "' is a letter or digit. ");				
                }
      else{
System.out.println("The character '" + ch3 + "' is neither a letter nor a digit.");
           }		
         }
       }
     }
  }
}

输出

Enter the first input:R
The character 'R' is a letter or digit. 
Enter the second input:9
The character '9' is a letter or digit. 
Enter the third input:A
The character 'A' is a letter or digit.

Java Character isLetterOrDigit() 方法

Character 类的 isLetterOrDigit(int codePoint) 方法用于确定给定的（或指定的）字符是否是字母或数字。

如果给定的字符满足 Character.isLetter(int codePoint) 或 Character.isDigit(int codePoint) 方法返回 true，则该字符被认为是字母或数字。

语法

参数

codePoint：需要测试的字符的 codePoint。

返回值

isLetter(int codePoint) 方法返回一个布尔值，即如果给定的（或指定的）字符是字母或数字，则返回 true。否则，该方法返回 false。

示例 4

public class JavaCharacterisLetterOrDigitExample4{
   public static void main(String[] args) {
    // Create four char primitives codePoint1, codePoint2, codePoint3 and codePoint4.
      int codePoint1;
      int codePoint2;
      int codePoint3;
      int codePoint4;
      // Assign the values to codePoint1, codePoint2, codePoint3 and codePoint4.
      codePoint1 = 26;
      codePoint2 = 134;
      codePoint3= 198;
      codePoint4 = 408;
      // Create four boolean primitives b1, b2, b3 and b4.
      boolean b1, b2, b3,b4;
      // Check whether the codePoint1, codePoint2, codePoint3 and codePoint4  are letters or digits or not and assign the results to b1, b2, b3 and b4.
      b1 = Character.isLetterOrDigit(codePoint1);
      b2 = Character.isLetterOrDigit(codePoint2);
      b3 = Character.isLetterOrDigit(codePoint3);
      b4 = Character.isLetterOrDigit(codePoint4);

      String str1 = "The first codePoint  '"+codePoint1 + "' is a letter or a  digit: " + b1;
      String str2 = "The second codePoint '"+codePoint2 + "' is a letter or a  digit: " + b2;
      String str3 = "The third codePoint  '"+codePoint3 + "' is a letter or a  digit: " + b3;
      String str4 = "The fourth codePoint '"+codePoint4 + "' is a letter or a digit: " + b4;
      // Print the values of str1, str2, str3 and str4.
      System.out.println(str1);
      System.out.println(str2);
      System.out.println(str3);
      System.out.println(str4);
   }
}

输出

The first codePoint  '26' is a letter or a  digit: false
The second codePoint '134' is a letter or a  digit: false
The third codePoint  '198' is a letter or a  digit: true
The fourth codePoint '408' is a letter or a digit: true

示例 5

import java.util.Scanner;
public class JavaChracterisLetterOrDigiExample5{
    public static void main(String[] args) {
    // Ask the user for first input.
       System.out.print("Enter the first input:");
    // Use the Scanner class to get the user input.
       Scanner s1 = new Scanner(System.in);
    // Gets the user input.
       char[] value1 = s1.nextLine().toCharArray();
    // Check whether the user input is a lettter or digit or not.
       for (char ch1 : value1) {
   boolean result1 = Character.isLetterOrDigit(ch1);
    // Print the first result.
       if(result1){
System.out.println("The character '" + ch1 + "' is a letter or digit. ");				
                  }
     else{
System.out.println("The character '" + ch1 + "' is neither a letter nor digit.");
           }		
       System.out.print("Enter the second input:");
       Scanner s2 = new Scanner(System.in);
       char[] value2 = s2.nextLine().toCharArray();
       for (char ch2 : value2) {
      boolean result2 = Character.isLetterOrDigit(ch2);
      if(result2){
System.out.println("The character '" + ch2 + "' is a letter or digit. ");				
                }
      else{
System.out.println("The character '" + ch2 + "' is neither a letter nor digit.");
        }		
      System.out.print("Enter the third input:");
       Scanner s3 = new Scanner(System.in);
       char[] value3 = s3.nextLine().toCharArray();
       for (char ch3 : value3) {
      boolean result3 = Character.isLetterOrDigit(ch3);
      if(result2){
System.out.println("The character '" + ch3 + "' is a letter or digit. ");				
                }
      else{
System.out.println("The character '" + ch3 + "' is neither a letter nor digit.");
           }		
         }
       }
     }
  }
}

输出

Enter the first input:A
The character 'A' is a letter or digit. 
Enter the second input:6
The character '6' is a letter or digit. 
Enter the third input:^
The character '^' is a letter or digit..

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Java Character isLetterOrDigit() 方法

注意：上述方法不能用于处理增补字符。为了处理增补字符，我们可以使用 isLetterOrDigit(int) 方法。

语法

参数

返回值

示例 1

示例 2

示例 3

Java Character isLetterOrDigit() 方法

语法

参数

返回值

示例 4

示例 5

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Java Character isLetterOrDigit() 方法

注意：上述方法不能用于处理增补字符。为了处理增补字符，我们可以使用 isLetterOrDigit(int) 方法。

语法

参数

返回值

示例 1

示例 2

示例 3

Java Character isLetterOrDigit() 方法

语法

参数

返回值

示例 4

示例 5

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