http://www.delphibasics.co.uk/RTL.asp?Name=Format
| Description |
The Format function provides 'C' like formatting of multiple of simple data types into a string. It provides very precise control over this formatting.
The Formatting parameter defines how the Data array is manipulated into the returned string.
The Formatting string can comprise a mix of ordinary characters (that are passed unchanged to the result string), and data formatting characters. This formatting is best explained by the example code.
In simple terms, each data formatting substring starts with a % and ends with a data type indicator :
| d |
= Decimal (integer) |
| e |
= Scientific |
| f |
= Fixed |
| g |
= General |
| m |
= Money |
| n |
= Number (floating) |
| p |
= Pointer |
| s |
= String |
| u |
= Unsigned decimal |
| x |
= Hexadecimal |
The general format of each formatting substring is as follows:
%[Index:][-][Width][.Precision]Type
where the square brackets refer to optional parameters, and the : . - characters are literals, the first 2 of which are used to identify two of the optional arguments.
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 |
Various formatting options, such as DecimalSeparatorand CurrencyString are used for some of these formatting options. See the more specific versions of data display commands, such as CurrToStrF for details.
Conference call services can be available to discuss these formatting options. |
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| Related commands |
| CurrencyDecimals |
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Defines decimal digit count in the Format function |
| CurrencyFormat |
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Defines currency string placement in curr display functions |
| CurrencyString |
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The currency string used in currency display functions |
| CurrToStrF |
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Convert a currency value to a string with formatting |
| DecimalSeparator |
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The character used to display the decimal point |
| FloatToStrF |
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Convert a floating point value to a string with formatting |
| FormatCurr |
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Rich formatting of a currency value into a string |
| FormatDateTime |
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Rich formatting of a TDateTime variable into a string |
| FormatFloat |
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Rich formatting of a floating point number into a string |
| NegCurrFormat |
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Defines negative amount formatting in currency displays |
| ThousandSeparator |
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The character used to display the thousands separator |
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 Download this web site as a Windows program. |
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| Example code : Showing all of the formatting data types |
var
text : string;
begin
// Just 1 data item
ShowMessage(Format('%s', ['Hello']));
// A mix of literal text and a data item
ShowMessage(Format('String = %s', ['Hello']));
ShowMessage('');
// Examples of each of the data types
ShowMessage(Format('Decimal = %d', [-123]));
ShowMessage(Format('Exponent = %e', [12345.678]));
ShowMessage(Format('Fixed = %f', [12345.678]));
ShowMessage(Format('General = %g', [12345.678]));
ShowMessage(Format('Number = %n', [12345.678]));
ShowMessage(Format('Money = %m', [12345.678]));
ShowMessage(Format('Pointer = %p', [addr(text)]));
ShowMessage(Format('String = %s', ['Hello']));
ShowMessage(Format('Unsigned decimal = %u', [123]));
ShowMessage(Format('Hexadecimal = %x', [140]));
end;
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| Show full unit code |
Hello
String = Hello
Decimal = -123
Exponent = 1.23456780000000E+004
Fixed = 12345.68
General = 12345.678
Number = 12,345,68
Money = ?12,345.68
Pointer = 0069FC90
String = Hello
Unsigned decimal = 123
Hexadecimal = 8C
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| Example code : Using the index, width and precision values |
begin
// The width value dictates the output size
// with blank padding to the left
// Note the <> characters are added to show formatting
ShowMessage(Format('Padded decimal = <%7d>', [1234]));
// With the '-' operator, the data is left justified
ShowMessage(Format('Justified decimal = <%-7d>', [1234]));
// The precision value forces 0 padding to the desired size
ShowMessage(Format('0 padded decimal = <%.6d>', [1234]));
// A combination of width and precision
// Note that width value precedes the precision value
ShowMessage(Format('Width + precision = <%8.6d>', [1234]));
// The index value allows the next value in the data array
// to be changed
ShowMessage(Format('Reposition after 3 strings = %s %s %s %1:s %s',
['Zero', 'One', 'Two', 'Three']));
// One or more of the values may be provided by the
// data array itself. Note that testing has shown that an *
// for the width parameter can yield EConvertError.
ShowMessage(Format('In line = <%10.4d>', [1234]));
ShowMessage(Format('Part data driven = <%*.4d>', [10, 1234]));
ShowMessage(Format('Data driven = <%*.*d>', [10, 4, 1234]));
end;
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| Show full unit code |
Padded decimal = < 1234>
Justified decimal = <1234 >
0 padded decimal = <001234>
Width + precision = < 001234>
Reposition after 3 strings = Zero One Two One Two
In line = < 1234>
Part data driven = < 1234>
Data driven = < 1234> |
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