Java.lang.Character.digit() 方法

描述

java.lang.Character.digit(char ch, int radix) 返回指定基数中字符 ch 的数值。

如果基数不在 MIN_RADIX ≤ radix ≤ MAX_RADIX 范围内，或者 ch 的值不是指定基数中的有效数字，则返回 -1。 如果以下至少一项为真，则字符是有效数字 −

• isDigit 方法对字符为真且字符的 Unicode 十进制数字值（或其单字符分解）小于指定的基数。 在这种情况下，返回十进制数字值。

• The character is one of the uppercase Latin letters 'A' through 'Z' and its code is less than radix + 'A' − 10. In this case, ch − 'A' + 10 is returned.

• The character is one of the lowercase Latin letters 'a' through 'z' and its code is less than radix + 'a' − 10. In this case, ch − 'a' + 10 is returned.

• The character is one of the fullwidth uppercase Latin letters A ('\uFF21') through Z ('\uFF3A') and its code is less than radix + '\uFF21' − 10. In this case, ch − '\uFF21' + 10 is returned.

• The character is one of the fullwidth lowercase Latin letters a ('\uFF41') through z ('\uFF5A') and its code is less than radix + '\uFF41' − 10. In this case, ch − '\uFF41' + 10 is returned.

声明

以下是 java.lang.Character.digit() 方法的声明。

public static int digit(char ch, int radix)

参数

• ch − 要转换的字符

• radix − 基数

返回值

该方法返回指定基数中的字符所代表的数值。

异常

NA

示例

下面的例子展示了 lang.Character.digit() 方法的使用。

package com.tutorialspoint;

import java.lang.*;

public class CharacterDemo {

   public static void main(String[] args) {

      // create 2 character primitives ch1, ch2
      char ch1, ch2;

      // assign values to ch1, ch2
      ch1 = '9';
      ch2 = '5';

      // create 2 int primitives i1, i2
      int i1, i2;

      // assign numeric value of ch1, ch2 to i1, i2 using radix
      i1 = Character.digit(ch1, 2);
      i2 = Character.digit(ch2, 10);

      String str1 = "Numeric value of " + ch1 + " in radix 2 is " + i1;
      String str2 = "Numeric value of " + ch2 + " in radix 10 is " + i2;

      // print i1, i2 values
      System.out.println( str1 );
      System.out.println( str2 );
   }
}

让我们编译并运行上面的程序，这将产生下面的结果 −

Numeric value of 9 in radix 2 is -1
Numeric value of 5 in radix 10 is 5