Delphi Basics : FormatFloat command

DelphiBasics

FormatFloat
Function

Rich formatting of a floating point number into a string

SysUtils unit

1	function FormatFloat(const Formatting string; Value Extended):string;
2	function FormatFloat (const Formatting string; Value Extended; FormatSettings TFormatSettings:string;

Description

The FormatFloat function provides rich Formatting of a floating point number Value into a string.

The Formatting string may contain a mix of freeform text and control characters:

0	: Forces digit display or 0
#	: Optional digit display
,	: Forces display of thousands
.	: Forces display of decimals
E+	: Forces signed exponent display
E-	: Optional sign exponent display
;	: Separator of +ve and -ve and zero values

These are best understood by looking at the sample code.

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.

Related commands

CurrencyDecimals		Defines decimal digit count in the Format function
CurrencyFormat		Defines currency string placement in curr display functions
CurrencyString		The currency string used in currency display functions
DecimalSeparator		The character used to display the decimal point
FloatToStrF		Convert a floating point value to a string with formatting
Format		Rich formatting of numbers and text into a string
FormatCurr		Rich formatting of a currency value into a string
FormatDateTime		Rich formatting of a TDateTime variable into a string
NegCurrFormat		Defines negative amount formatting in currency displays
StrToFloat		Convert a number string into a floating point value
ThousandSeparator		The character used to display the thousands separator

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Example code : Showing all of the formatting data types

var
  float : extended;

begin
  // Set up our floating point number
  float := 1234.567;

  // Display a sample value using all of the format options

  // Round out the decimal value
  ShowMessage('##### : '+FormatFloat('#####', float));
  ShowMessage('00000 : '+FormatFloat('00000', float));
  ShowMessage('0     : '+FormatFloat('0'    , float));
  ShowMessage('#,##0 : '+FormatFloat('#,##0', float));
  ShowMessage(',0    : '+FormatFloat(',0'   , float));
  ShowMessage('');

  // Include the decimal value
  ShowMessage('0.#### : '+FormatFloat('0.####', float));
  ShowMessage('0.0000 : '+FormatFloat('0.0000', float));
  ShowMessage('');

  // Scientific format
  ShowMessage('0.0000000E+00 : '+FormatFloat('0.0000000E+00', float));
  ShowMessage('0.0000000E-00 : '+FormatFloat('0.0000000E-00', float));
  ShowMessage('#.#######E-## : '+FormatFloat('#.#######E-##', float));
  ShowMessage('');

  // Include freeform text
  ShowMessage('"Value = "0.0 : '+FormatFloat('"Value = "0.0', float));
  ShowMessage('');

  // Different formatting for negative numbers
  ShowMessage('0.0 : '+FormatFloat('0.0'              , -1234.567));
  ShowMessage('0.0 "CR";0.0 "DB" : '+
              FormatFloat('0.0 "CR";0.0 "DB"', -1234.567));
  ShowMessage('0.0 "CR";0.0 "DB" : '+
              FormatFloat('0.0 "CR";0.0 "DB"',  1234.567));
  ShowMessage('');

  // Different format for zero value
  ShowMessage('0.0 : '+FormatFloat('0.0' , 0.0));
  ShowMessage('0.0;-0.0;"Nothing" : '+
              FormatFloat('0.0;-0.0;"Nothing"', 0.0));
end;

Show full unit code

  ##### : 1235
  00000 : 01235
  0 : 1235
  #,##0 : 1,235
  ,0 : 1,235

  0.#### : 1234.567
  0.0000 : 1234.5670

  0.0000000E+00 : 1.2345670E+03
  0.0000000E-00 : 1.2345670E03
  #.#######E-## : 1.234567E3

  "Value = " : Value = 1234.6

  0.0 : -1234.6
  0.0 "CR";0.0 "DB" : 1234.6 DB
  0.0 "CR";0.0 "DB" : 1234.6 CR

  0.0 : 0.0
  0.0;-0.0;"Nothing" : Nothing