# Math.Log10(Double) メソッド

## 定義

``````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``

d
Double

#### 戻り値

`d` パラメーター 戻り値
`d` の底 10 の log。つまり、log 10`d`
ゼロNegativeInfinity
NaN
NaN と等価です。NaN
PositiveInfinity と等価です。PositiveInfinity

## 例

``````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.
``````
``````open System

let numbers =
[ -1.; 0; 0.105; 0.5; 0.798; 1; 4; 6.9; 10
50; 100; 500; 1000; Double.MaxValue ]

for number in numbers do
// the F# log10 function may be used instead
printfn \$"The base 10 log of {number} is {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.
``````

## 注釈

パラメーター `d` は、基数 10 として指定されます。

このメソッドは基になる C ランタイムを呼び出します。正確な結果または有効な入力範囲は、オペレーティング システムやアーキテクチャによって異なる場合があります。