| Description |
Attempts to parse the Value string into a value in the range +/-3.402823e38, returning a Single object with this value.
The Style parameter determines the allowed number content. It is an enumerated type that is treated as a set of flags (it has the [Flags] attribute. This means that multiple values may be set, using logical or. The possible values are :
| AllowCurrencySymbol | Allow for ?,$ ... |
| AllowExponent | E+000 format |
| AllowThousands | For example : 1,000,000 |
| AllowDecimalPoint | For example : 123.456 |
| AllowParentheses | For example (1234) |
| AllowTrailingSign | For example : 123- |
| AllowLeadingSign | For example : -123 |
| AllowTrailingWhite | Allow trailing blanks |
| AllowLeadingWhite | Allow leading blanks |
| AllowHexSpecifier | For example : 0x2bcd |
The FormatProvider option allows for customised formatting and is beyond the scope of Delphi Basics.
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| | Notes | Warning : An exception is thrown if the parse encounters unexpected characters.
Static methods are not methods of an object - they are simply class functions or procedures available at any time.
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| | References | NumberStyles
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| Microsoft MSDN Links |
System
System.Single
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| A simple example |
program Project1;
{$APPTYPE CONSOLE}
var
dblStr : String;
result : Single;
begin
dblStr := '-123.45';
result := System.Single.Parse(dblStr);
Console.WriteLine('''' + dblStr + ''' parses to {0}', result.ToString);
Console.ReadLine;
end.
| | Show full unit code | '-123.45' parses to -123.45
| | | Using NumberStyles | program Project1;
{$APPTYPE CONSOLE}
uses
System.Globalization;
var
style : NumberStyles;
dblStr : String;
result : Double;
begin
// Allow for hex values and leading/trailing blanks
style := NumberStyles.AllowLeadingWhite or
NumberStyles.AllowTrailingWhite or
NumberStyles.AllowThousands;
dblStr := ' 123,456,789 ';
result := System.Double.Parse(dblStr, style);
Console.WriteLine('''' + dblStr + ''' parses to {0}', result.ToString);
// Or more simply using one combined number style value
style := NumberStyles.HexNumber;
dblStr := ' AC '; // Hex AC = 189
result := System.Double.Parse(dblStr, style);
Console.WriteLine('''' + dblStr + ''' parses to {0}', result.ToString);
Console.ReadLine;
end.
| | Show full unit code | ' 123,456,789 ' parses to 123456789
' AC ' parses to 189
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