Math.Log10(Double) 方法

定义

返回指定数字以 10 为底的对数。Returns the base 10 logarithm of a specified number.

public:
 static double Log10(double d);
public static double Log10 (double d);
static member Log10 : double -> double
Public Shared Function Log10 (d As Double) As Double

参数

d
Double

要查找其对数的数字。A number whose logarithm is to be found.

返回

Double

下表中的值之一。One of the values in the following table.

d 参数d parameter 返回值Return value
Positive d 的以 10 为底的对数,即 log 10dThe base 10 log of d; that is, log 10d.
Zero NegativeInfinity
负数Negative NaN
等于 NaNEqual to NaNNaN
等于 PositiveInfinityEqual to PositiveInfinityPositiveInfinity

示例

下面的示例使用 Log10 方法为所选值返回以10为底的对数。The following example uses the Log10 method to return the base 10 logarithm for selected values.

using System;

public class Example
{
   public static void Main()
   {
      double[] numbers = {-1, 0, .105, .5, .798, 1, 4, 6.9, 10, 50,
                          100, 500, 1000, Double.MaxValue};

      foreach (double number in numbers)
         Console.WriteLine("The base 10 log of {0} is {1}.",
                           number, Math.Log10(number));
   }
}
// The example dislays the following output:
//       The base 10 log of -1 is NaN.
//       The base 10 log of 0 is -Infinity.
//       The base 10 log of 0.105 is -0.978810700930062.
//       The base 10 log of 0.5 is -0.301029995663981.
//       The base 10 log of 0.798 is -0.0979971086492706.
//       The base 10 log of 1 is 0.
//       The base 10 log of 4 is 0.602059991327962.
//       The base 10 log of 6.9 is 0.838849090737255.
//       The base 10 log of 10 is 1.
//       The base 10 log of 50 is 1.69897000433602.
//       The base 10 log of 100 is 2.
//       The base 10 log of 500 is 2.69897000433602.
//       The base 10 log of 1000 is 3.
//       The base 10 log of 1.79769313486232E+308 is 308.254715559917.
Module Example
   Public Sub Main()
      Dim numbers() As Double = {-1, 0, .105, .5, .798, 1, 4, 6.9, 10, 50, _
                                 100, 500, 1000, Double.MaxValue}
      
      For Each number As Double In numbers
         Console.WriteLine("The base 10 log of {0} is {1}.", _
                           number, Math.Log10(number))
      Next
   End Sub
End Module
' The example displays the following output:
'       The base 10 log of -1 is NaN.
'       The base 10 log of 0 is -Infinity.
'       The base 10 log of 0.105 is -0.978810700930062.
'       The base 10 log of 0.5 is -0.301029995663981.
'       The base 10 log of 0.798 is -0.0979971086492706.
'       The base 10 log of 1 is 0.
'       The base 10 log of 4 is 0.602059991327962.
'       The base 10 log of 6.9 is 0.838849090737255.
'       The base 10 log of 10 is 1.
'       The base 10 log of 50 is 1.69897000433602.
'       The base 10 log of 100 is 2.
'       The base 10 log of 500 is 2.69897000433602.
'       The base 10 log of 1000 is 3.
'       The base 10 log of 1.79769313486232E+308 is 308.254715559917.

注解

参数 d 被指定为以10为基数的数字。Parameter d is specified as a base 10 number.

此方法调入基础 C 运行时,并且不同的操作系统或体系结构的确切结果或有效输入范围可能不同。This method calls into the underlying C runtime, and the exact result or valid input range may differ between different operating systems or architectures.

适用于