| Description |
The StrToFloat function converts a number string, FloatString such as '123.456' into an Extended floating point number.
It supports integer, floating point, and scientific (exponent) formats.
If a decimal point appears in FloatString, then it must match the current DecimalSeparator value.
Version 2 of this function is for use within threads. You furnish the FormatSettings record before invoking the call. It takes a local copy of global formatting variables that make the routine thread safe.
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| Notes |
The EConvertError exception is thrown if there are errors in FloatString, such as trailing blanks or invalid decimal characters.
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| Related commands |
| Extended |
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The floating point type with the highest capacity and precision |
| FloatToStr |
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Convert a floating point value to a string |
| FloatToStrF |
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Convert a floating point value to a string with formatting |
| TFormatSettings |
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A record for holding locale values for thread-safe functions |
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| Example code : Converting a scientific format number string |
// Full Unit code.
// -----------------------------------------------------------
// You must store this code in a unit called Unit1 with a form
// called Form1 that has an OnCreate event called FormCreate.
unit Unit1;
interface
uses
SysUtils, // Unit containing the StrToFloat command
Forms, Dialogs;
type
TForm1 = class(TForm)
procedure FormCreate(Sender: TObject);
end;
var
Form1: TForm1;
implementation
{$R *.dfm} // Include form definitions
procedure TForm1.FormCreate(Sender: TObject);
var
stringValue : string;
floatValue : Extended;
begin
// Set up the source string containing a number representation
stringValue := '123.456E+002';
// Convert it to a floating point number
floatValue := StrToFloat(stringValue);
// And display the value
ShowMessage(stringValue+' = '+FloatToStr(floatValue));
end;
end.
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| Hide full unit code |
123.456E+002 = 12345.6
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| Example code : Catching string conversion errors |
var
A : Extended;
begin
// We will catch conversion errors
try
A := StrToFloat('10 E 2'); // Middle blanks are not supported
except
on Exception : EConvertError do
ShowMessage(Exception.Message);
end;
try
A := StrToFloat('$FF'); // Hexadecimal values are not supported
except
on Exception : EConvertError do
ShowMessage(Exception.Message);
end;
end;
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| Show full unit code |
'10 E 2' is not a valid floating point value
'$FF' is not a valid floating point value
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