指定したカルチャに固有の書式による数値の文字列形式を、それと等価な単精度浮動小数点数に変換します。
Overloads Public Shared Function Parse( _
ByVal s As String, _ ByVal provider As IFormatProvider _) As Single
[C#]
public static float Parse(strings,IFormatProviderprovider);
[C++]
public: static float Parse(String* s,IFormatProvider* provider);
[JScript]
public static function Parse(
s : String,provider : IFormatProvider) : float;
パラメータ
- s
変換する数値を表す文字列。 - provider
s に関するカルチャに固有の書式情報を提供する IFormatProvider 。
戻り値
s で指定した数値または記号に等しい単精度浮動小数点数。
例外
| 例外の種類 | 条件 |
|---|---|
| ArgumentNullException | s が null 参照 (Visual Basic では Nothing) です。 |
| FormatException | s が、有効な書式の数値ではありません。 |
| OverflowException | s が MinValue 未満の数値か、 MaxValue より大きい数値を表しています。 |
解説
s パラメータには、 PositiveInfinitySymbol 、 NegativeInfinitySymbol 、 NaNSymbol 、または次の書式の文字列を格納できます。
[ws][sign]integral-digits[.[fractional-digits]][e[sign]exponential-digits][ws]
省略可能な項目は、角かっこ ([および]) で囲まれています。"digits" という語を含む項目は、0 から 9 までの一連の数字から構成されます。
- ws
一連の空白文字。 - sign
負の記号または正の記号。 - integral-digits
数値の整数部分を指定する一連の数字。一連の整数の桁は、区切り記号によって区切られる場合があります。たとえば、カルチャによっては、桁区切り文字としてコンマ (,) が使用されます。小数の桁が存在する場合は、整数の桁はなくてもかまいません。 - '.'
カルチャに固有の小数点記号。 - fractional-digits
数値の小数部分を指定する一連の数字。 - 'e'
指数表記を示す大文字または小文字の 'e'。 - exponential-digits
指数部を指定する一連の数字。
s の例には、"100"、"-123,456,789"、"123.45e+6"、"+500"、"5e2"、"3.1416"、"600."、"-.123"、"-Infinity" などがあります。
Parse のこのバージョンでは、 NumberStyles 値、 Float および AllowThousands 、および指定した数値書式情報を使用します。 provider が null 参照 (Visual Basic では Nothing) の場合や、 NumberFormatInfo を取得できない場合は、現在のシステムのカルチャの書式情報が使用されます。
数値書式の詳細については、「 書式設定の概要 」のトピックを参照してください。
使用例
[Visual Basic, C#, C++] IFormatProvider オブジェクトを使用し、 String 形式の Single の値を Parse メソッドで解析するコード例を次に示します。
' Example of the Single.Parse( ) methods.
Imports System
Imports System.Globalization
Imports Microsoft.VisualBasic
Module SingleParseDemo
' Get the exception type name; remove the namespace prefix.
Function GetExceptionType( ex As Exception ) As String
Dim exceptionType As String = ex.GetType( ).ToString( )
Return exceptionType.Substring( _
exceptionType.LastIndexOf( "."c ) + 1 )
End Function
Sub SingleParse( styles As NumberStyles, _
provider As IFormatProvider )
Dim singleFormats As String( ) = { _
" 987.654E-2", " 987,654E-2", "(98765,43210)", _
"9,876,543.210", "9.876.543,210", "98_76_54_32,19" }
' Parse each string in the singleFormats array, using
' NumberStyles and IFormatProvider, if specified.
Dim singleString As String
For Each singleString In singleFormats
Dim singleNumber As Single
' Display the first part of the output line.
Console.Write( " Parse of {0,-20}", _
String.Format( """{0}""", singleString ) )
' Use the appropriate Single.Parse overload, based on
' the parameters that are specified.
Try
If provider Is Nothing Then
If styles < 0 Then
singleNumber = Single.Parse( singleString )
Else
singleNumber = _
Single.Parse( singleString, styles )
End If
ElseIf styles < 0 Then
singleNumber = _
Single.Parse( singleString, provider )
Else
singleNumber = Single.Parse( _
singleString, styles, provider )
End If
' Display the resulting value if Parse succeeded.
Console.WriteLine( "success: {0}", singleNumber )
' Display the exception type if Parse failed.
Catch ex As Exception
Console.WriteLine( "failed: {0}", _
GetExceptionType( ex ) )
End Try
Next singleString
End Sub
Sub Main( )
Console.WriteLine( "This example of" & vbCrLf & _
" Single.Parse( String )," & vbCrLf & _
" Single.Parse( String, NumberStyles )," & vbCrLf & _
" Single.Parse( String, IFormatProvider ), and" & _
vbCrLf & " Single.Parse( String, NumberStyles, " & _
"IFormatProvider )" & vbCrLf & "generates the " & _
"following output when run in the [{0}] culture.", _
CultureInfo.CurrentCulture.Name )
Console.WriteLine( "Several string representations " & _
"of Single values are parsed." )
' Do not use IFormatProvider or NumberStyles.
Console.WriteLine( vbCrLf & _
"NumberStyles and IFormatProvider are not " & _
"used; current culture is [{0}]:", _
CultureInfo.CurrentCulture.Name )
SingleParse( CType( -1, NumberStyles ), Nothing )
' Use the NumberStyle for Currency.
Console.WriteLine( vbCrLf & "NumberStyles.Currency " & _
"is used; IFormatProvider is not used:" )
SingleParse( NumberStyles.Currency, Nothing )
' Create a CultureInfo object for another culture. Use
' [Dutch - The Netherlands] unless the current culture
' is Dutch language. In that case use [English - U.S.].
Dim cultureName As String = IIf( _
CultureInfo.CurrentCulture.Name.Substring( 0, 2 ) = _
"nl", "en-US", "nl-NL" )
Dim culture As New CultureInfo( cultureName )
Console.WriteLine( vbCrLf & _
"NumberStyles is not used; [{0}] culture " & _
"IFormatProvider is used:", culture.Name )
SingleParse( CType( -1, NumberStyles ), culture )
' Get the NumberFormatInfo object from CultureInfo, and
' then change the digit group size to 2 and the digit
' separator to '_'.
Dim numInfo As NumberFormatInfo = culture.NumberFormat
numInfo.NumberGroupSizes = New Integer( ) { 2 }
numInfo.NumberGroupSeparator = "_"
' Use the NumberFormatInfo object as the IFormatProvider.
Console.WriteLine( vbCrLf & _
"NumberStyles.Currency is used, group size = 2, " & _
"separator = ""_"":" )
SingleParse( NumberStyles.Currency, numInfo )
End Sub
End Module
' This example of
' Single.Parse( String ),
' Single.Parse( String, NumberStyles ),
' Single.Parse( String, IFormatProvider ), and
' Single.Parse( String, NumberStyles, IFormatProvider )
' generates the following output when run in the [en-US] culture.
' Several string representations of Single values are parsed.
'
' NumberStyles and IFormatProvider are not used; current culture is [en-US]:
' Parse of " 987.654E-2" success: 9.87654
' Parse of " 987,654E-2" success: 9876.54
' Parse of "(98765,43210)" failed: FormatException
' Parse of "9,876,543.210" success: 9876543
' Parse of "9.876.543,210" failed: FormatException
' Parse of "98_76_54_32,19" failed: FormatException
'
' NumberStyles.Currency is used; IFormatProvider is not used:
' Parse of " 987.654E-2" failed: FormatException
' Parse of " 987,654E-2" failed: FormatException
' Parse of "(98765,43210)" success: -9.876543E+09
' Parse of "9,876,543.210" success: 9876543
' Parse of "9.876.543,210" failed: FormatException
' Parse of "98_76_54_32,19" failed: FormatException
'
' NumberStyles is not used; [nl-NL] culture IFormatProvider is used:
' Parse of " 987.654E-2" success: 9876.54
' Parse of " 987,654E-2" success: 9.87654
' Parse of "(98765,43210)" failed: FormatException
' Parse of "9,876,543.210" failed: FormatException
' Parse of "9.876.543,210" success: 9876543
' Parse of "98_76_54_32,19" failed: FormatException
'
' NumberStyles.Currency is used, group size = 2, separator = "_":
' Parse of " 987.654E-2" failed: FormatException
' Parse of " 987,654E-2" failed: FormatException
' Parse of "(98765,43210)" success: -98765.43
' Parse of "9,876,543.210" failed: FormatException
' Parse of "9.876.543,210" success: 9876543
' Parse of "98_76_54_32,19" success: 9.876543E+07
[C#]
// Example of the Single.Parse( ) methods.
using System;
using System.Globalization;
class SingleParseDemo
{
// Get the exception type name; remove the namespace prefix.
static string GetExceptionType( Exception ex )
{
string exceptionType = ex.GetType( ).ToString( );
return exceptionType.Substring(
exceptionType.LastIndexOf( '.' )+1 );
}
// Parse each string in the singleFormats array, using
// NumberStyles and IFormatProvider, if specified.
static void SingleParse( NumberStyles styles,
IFormatProvider provider )
{
string[ ] singleFormats = {
" 987.654E-2", " 987,654E-2", "(98765,43210)",
"9,876,543.210", "9.876.543,210", "98_76_54_32,19" };
foreach( string singleString in singleFormats )
{
float singleNumber;
// Display the first part of the output line.
Console.Write( " Parse of {0,-20}",
String.Format( "\"{0}\"", singleString ) );
try
{
// Use the appropriate Single.Parse overload, based
// on the parameters that are specified.
if( provider == null )
{
if( styles < 0 )
singleNumber = Single.Parse( singleString );
else
singleNumber =
Single.Parse( singleString, styles );
}
else if( styles < 0 )
singleNumber =
Single.Parse( singleString, provider );
else
singleNumber =
Single.Parse( singleString, styles, provider );
// Display the resulting value if Parse succeeded.
Console.WriteLine( "success: {0}", singleNumber );
}
catch( Exception ex )
{
// Display the exception type if Parse failed.
Console.WriteLine( "failed: {0}",
GetExceptionType( ex ) );
}
}
}
public static void Main( )
{
Console.WriteLine( "This example of\n" +
" Single.Parse( String ),\n" +
" Single.Parse( String, NumberStyles ),\n" +
" Single.Parse( String, IFormatProvider ), and\n" +
" Single.Parse( String, NumberStyles, " +
"IFormatProvider )\ngenerates the " +
"following output when run in the [{0}] culture.",
CultureInfo.CurrentCulture.Name );
Console.WriteLine( "Several string representations " +
"of Single values are parsed." );
// Do not use IFormatProvider or NumberStyles.
Console.WriteLine( "\nNumberStyles and IFormatProvider " +
"are not used; current culture is [{0}]:",
CultureInfo.CurrentCulture.Name );
SingleParse( ( (NumberStyles)( -1 ) ), null );
// Use the NumberStyle for Currency.
Console.WriteLine( "\nNumberStyles.Currency " +
"is used; IFormatProvider is not used:" );
SingleParse( NumberStyles.Currency, null );
// Create a CultureInfo object for another culture. Use
// [Dutch - The Netherlands] unless the current culture
// is Dutch language. In that case use [English - U.S.].
string cultureName =
CultureInfo.CurrentCulture.Name.Substring( 0, 2 ) == "nl" ?
"en-US" : "nl-NL";
CultureInfo culture = new CultureInfo( cultureName );
Console.WriteLine( "\nNumberStyles is not used; " +
"[{0}] culture IFormatProvider is used:",
culture.Name );
SingleParse( ( (NumberStyles)( -1 ) ), culture );
// Get the NumberFormatInfo object from CultureInfo, and
// then change the digit group size to 2 and the digit
// separator to '_'.
NumberFormatInfo numInfo = culture.NumberFormat;
numInfo.NumberGroupSizes = new int[ ] { 2 };
numInfo.NumberGroupSeparator = "_";
// Use the NumberFormatInfo object as the IFormatProvider.
Console.WriteLine( "\nNumberStyles.Currency is used, " +
"group size = 2, separator = \"_\":" );
SingleParse( NumberStyles.Currency, numInfo );
}
}
/*
This example of
Single.Parse( String ),
Single.Parse( String, NumberStyles ),
Single.Parse( String, IFormatProvider ), and
Single.Parse( String, NumberStyles, IFormatProvider )
generates the following output when run in the [en-US] culture.
Several string representations of Single values are parsed.
NumberStyles and IFormatProvider are not used; current culture is [en-US]:
Parse of " 987.654E-2" success: 9.87654
Parse of " 987,654E-2" success: 9876.54
Parse of "(98765,43210)" failed: FormatException
Parse of "9,876,543.210" success: 9876543
Parse of "9.876.543,210" failed: FormatException
Parse of "98_76_54_32,19" failed: FormatException
NumberStyles.Currency is used; IFormatProvider is not used:
Parse of " 987.654E-2" failed: FormatException
Parse of " 987,654E-2" failed: FormatException
Parse of "(98765,43210)" success: -9.876543E+09
Parse of "9,876,543.210" success: 9876543
Parse of "9.876.543,210" failed: FormatException
Parse of "98_76_54_32,19" failed: FormatException
NumberStyles is not used; [nl-NL] culture IFormatProvider is used:
Parse of " 987.654E-2" success: 9876.54
Parse of " 987,654E-2" success: 9.87654
Parse of "(98765,43210)" failed: FormatException
Parse of "9,876,543.210" failed: FormatException
Parse of "9.876.543,210" success: 9876543
Parse of "98_76_54_32,19" failed: FormatException
NumberStyles.Currency is used, group size = 2, separator = "_":
Parse of " 987.654E-2" failed: FormatException
Parse of " 987,654E-2" failed: FormatException
Parse of "(98765,43210)" success: -98765.43
Parse of "9,876,543.210" failed: FormatException
Parse of "9.876.543,210" success: 9876543
Parse of "98_76_54_32,19" success: 9.876543E+07
*/
[C++]
// Example of the Single::Parse( ) methods.
#using <mscorlib.dll>
using namespace System;
using namespace System::Globalization;
using namespace System::Collections;
// Get the exception type name; remove the namespace prefix.
String* GetExceptionType( Exception* ex )
{
String* exceptionType = ex->GetType( )->ToString( );
return exceptionType->Substring(
exceptionType->LastIndexOf( '.' ) + 1 );
}
// Parse each string in the singleFormats array, using
// NumberStyles and IFormatProvider, if specified.
void SingleParse( NumberStyles styles, IFormatProvider* provider )
{
String* singleFormats[ ] = __gc new String*[ 6 ];
singleFormats[ 0 ] = S" 987.654E-2";
singleFormats[ 1 ] = S"987,654E-2 ";
singleFormats[ 2 ] = S"(98765,43210)";
singleFormats[ 3 ] = S"9,876,543.210";
singleFormats[ 4 ] = S"9.876.543,210";
singleFormats[ 5 ] = S"98_76_54_32,19";
// Code foreach( String* singleString in singleFormats ).
IEnumerator* myEnum = singleFormats->GetEnumerator( );
while( myEnum->MoveNext( ) )
{
String* singleString =
__try_cast<String*>( myEnum->Current );
float singleNumber;
// Display the first part of the output line.
Console::Write( S" Parse of {0,-20}",
String::Format( S"\"{0}\"", singleString ) );
try
{
// Use the appropriate Single::Parse overload, based on
// the parameters that are specified.
if( provider == (IFormatProvider*)0 )
{
if( styles < 0 )
singleNumber = Single::Parse( singleString );
else
singleNumber =
Single::Parse( singleString, styles );
}
else if( styles < 0 )
singleNumber =
Single::Parse( singleString, provider );
else
singleNumber =
Single::Parse( singleString, styles, provider );
// Display the resulting value if Parse succeeded.
Console::WriteLine( S"success: {0}",
__box( singleNumber ) );
}
catch( Exception* ex )
{
// Display the exception type if Parse failed.
Console::WriteLine( S"failed: {0}",
GetExceptionType( ex ) );
}
}
}
void main( )
{
IFormatProvider* null = (IFormatProvider*)0;
Console::WriteLine( S"This example of\n"
S" Single::Parse( String* ),\n"
S" Single::Parse( String*, NumberStyles ),\n"
S" Single::Parse( String*, IFormatProvider* ), and\n"
S" Single::Parse( String*, NumberStyles, "
S"IFormatProvider* )\ngenerates the "
S"following output when run in the [{0}] culture.",
CultureInfo::CurrentCulture->Name );
Console::WriteLine( S"Several string representations "
S"of Single values are parsed." );
// Do not use IFormatProvider or NumberStyles.
Console::WriteLine( S"\nNumberStyles and IFormatProvider "
S"are not used; current culture is [{0}]:",
CultureInfo::CurrentCulture->Name );
SingleParse( ( (NumberStyles)( -1 ) ), null );
// Use the NumberStyle for Currency.
Console::WriteLine( S"\nNumberStyles::Currency "
S"is used; IFormatProvider is not used:" );
SingleParse( NumberStyles::Currency, null );
// Create a CultureInfo object for another culture. Use
// [Dutch - The Netherlands] unless the current culture
// is Dutch language. In that case use [English - U.S.].
String* cultureName =
CultureInfo::CurrentCulture->Name->Substring( 0, 2 ) == S"nl" ?
S"en-US" : S"nl-NL";
CultureInfo* culture = new CultureInfo( cultureName );
Console::WriteLine( S"\nNumberStyles is not used; "
S"[{0}] culture IFormatProvider is used:",
culture->Name );
SingleParse( ( (NumberStyles)( -1 ) ), culture );
// Get the NumberFormatInfo object from CultureInfo, and
// then change the digit group size to 2 and the digit
// separator to '_'.
NumberFormatInfo* numInfo = culture->NumberFormat;
Int32 sizes __gc [] = { 2 };
numInfo->NumberGroupSizes = sizes;
numInfo->NumberGroupSeparator = S"_";
// Use the NumberFormatInfo object as the IFormatProvider.
Console::WriteLine( S"\nNumberStyles::Currency is used, "
S"group size = 2, separator = \"_\":" );
SingleParse( NumberStyles::Currency, numInfo );
}
/*
This example of
Single::Parse( String* ),
Single::Parse( String*, NumberStyles ),
Single::Parse( String*, IFormatProvider* ), and
Single::Parse( String*, NumberStyles, IFormatProvider* )
generates the following output when run in the [en-US] culture.
Several string representations of Single values are parsed.
NumberStyles and IFormatProvider are not used; current culture is [en-US]:
Parse of " 987.654E-2" success: 9.87654
Parse of "987,654E-2 " success: 9876.54
Parse of "(98765,43210)" failed: FormatException
Parse of "9,876,543.210" success: 9876543
Parse of "9.876.543,210" failed: FormatException
Parse of "98_76_54_32,19" failed: FormatException
NumberStyles::Currency is used; IFormatProvider is not used:
Parse of " 987.654E-2" failed: FormatException
Parse of "987,654E-2 " failed: FormatException
Parse of "(98765,43210)" success: -9.876543E+09
Parse of "9,876,543.210" success: 9876543
Parse of "9.876.543,210" failed: FormatException
Parse of "98_76_54_32,19" failed: FormatException
NumberStyles is not used; [nl-NL] culture IFormatProvider is used:
Parse of " 987.654E-2" success: 9876.54
Parse of "987,654E-2 " success: 9.87654
Parse of "(98765,43210)" failed: FormatException
Parse of "9,876,543.210" failed: FormatException
Parse of "9.876.543,210" success: 9876543
Parse of "98_76_54_32,19" failed: FormatException
NumberStyles::Currency is used, group size = 2, separator = "_":
Parse of " 987.654E-2" failed: FormatException
Parse of "987,654E-2 " failed: FormatException
Parse of "(98765,43210)" success: -98765.43
Parse of "9,876,543.210" failed: FormatException
Parse of "9.876.543,210" success: 9876543
Parse of "98_76_54_32,19" success: 9.876543E+07
*/
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をクリックします。
必要条件
プラットフォーム: Windows 98, Windows NT 4.0, Windows Millennium Edition, Windows 2000, Windows XP Home Edition, Windows XP Professional, Windows Server 2003 ファミリ, .NET Compact Framework - Windows CE .NET, Common Language Infrastructure (CLI) Standard
参照
Single 構造体 | Single メンバ | System 名前空間 | Single.Parse オーバーロードの一覧 | 書式設定の概要 | ToString