Convert string with commas to float

Question

Is there a built-in Delphi function which would convert a string such as '3,232.00' to float? StrToFloat raises an exception because of the comma. Or is the only way to strip out the comma first and then do StrToFloat?

Thanks.

Answer 1

Try: StrToFloat(StringReplace('3,232.00', ',', '') It should get rid of the commas before doing the conversion.

In C# / VB.NET I use would use something like decimal.convert("3,232.00", ",", "");

I know of no way to do the conversion without stripping out the extra characters. In fact, I have a special function in my library that strips out commas and currency symbols. So a actually call MyConverer.decimalConverter("$3,232.00");

Answer 2

below is what i use. there might be more efficient ways, but this works for me. in short, no, i don't know of any built-in delphi function that will convert a string-float containing commas to a float

{~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  safeFloat

  Strips many bad characters from a string and returns it as a double.
}
function safeFloat(sStringFloat : AnsiString) : double;
var
  dReturn : double;

begin
  sStringFloat := stringReplace(sStringFloat, '%', '', [rfIgnoreCase, rfReplaceAll]);
  sStringFloat := stringReplace(sStringFloat, '$', '', [rfIgnoreCase, rfReplaceAll]);
  sStringFloat := stringReplace(sStringFloat, ' ', '', [rfIgnoreCase, rfReplaceAll]);
  sStringFloat := stringReplace(sStringFloat, ',', '', [rfIgnoreCase, rfReplaceAll]);
  try
    dReturn := strToFloat(sStringFloat);
  except
    dReturn := 0;
  end;
  result := dReturn;

end;

Answer 3

I had the same problem when my Users need to enter 'scientific' values such as "1,234.06mV". Here there is a comma, a multiplier (m=x0.001) and a unit (V). I created a 'wide' format converter routine to handle these situtations. Brian

Answer 4

Do you exactly know, that '.' is decimal separator and ',' is thousand separator (always)? If so, then you should fill the TFormatSettings record and pass it to StrToFloat.

FillChar(FS, SizeOf(FS), 0);
... // filling other fields
FS.ThousandSeparator := ',';
FS.DecimalSeparator := '.';
V := StrToFloat(S, FS);

Answer 5

function StrToFloat_Universal( pText : string ): Extended;
const
   EUROPEAN_ST = ',';
   AMERICAN_ST = '.';
var
  lformatSettings : TFormatSettings;
  lFinalValue     : string;
  lAmStDecimalPos : integer;
  lIndx           : Byte;
  lIsAmerican     : Boolean;
  lIsEuropean     : Boolean;

begin
  lIsAmerican := False;
  lIsEuropean := False;
  for lIndx := Length( pText ) - 1 downto 0 do
  begin
    if ( pText[ lIndx ] = AMERICAN_ST ) then
    begin
      lIsAmerican := True;
      pText := StringReplace( pText, ',', '', [ rfIgnoreCase, rfReplaceAll ]);  //get rid of thousand incidental separators
      Break;
    end;
    if ( pText[ lIndx ] = EUROPEAN_ST ) then
    begin
      lIsEuropean := True;
      pText := StringReplace( pText, '.', '', [ rfIgnoreCase, rfReplaceAll ]);  //get rid of thousand incidental separators
      Break;
    end;
  end;
  GetLocaleFormatSettings( LOCALE_SYSTEM_DEFAULT, lformatSettings );
  if ( lformatSettings.DecimalSeparator = EUROPEAN_ST ) then
  begin
    if lIsAmerican then
    begin
      lFinalValue := StringReplace( pText, '.', ',', [ rfIgnoreCase, rfReplaceAll ] );
    end;
  end;
  if ( lformatSettings.DecimalSeparator = AMERICAN_ST ) then
  begin
    if lIsEuropean then
    begin
      lFinalValue := StringReplace( pText, ',', '.', [ rfIgnoreCase, rfReplaceAll ] );
    end;
  end;
  pText  := lFinalValue;
  Result := StrToFloat( pText, lformatSettings );
end;