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Module: FoundationLite

Creates a string from a double number using a proper format.


Useful for preparing a number for display or communication with specific number of fractional digits, sign etc.
Name Type Range Description
Input value
inDouble Double Input real
Input value
inIntegerDigitCount Integer 0 - 1000 How many characters the integer part of the input real should have at least
Input value
inFractionalDigitCount Integer 0 - 100 How many characters the fractional part of the input real should have
Input value
inDecimalMark String The symbol used to separate the integer part from the fractional part of the number
Input value
inTrailingCharacter String Defines the trailing character
Input value
inForceSignPrinting Bool Forces printing the sign of the number even if the number is positive
Input value
inSuffix String Defines a suffix. Generally it is an unit of value (e.g. mm)
Output value
outString String Output string


inDouble = 2.7182818284590452
inIntegerDigitCount = 2
inFractionalDigitCount = 2
inDecimalMark = ","
inTrailingCharacter = "0"
inForceSignPrinting = False
inSuffix = "..."
outString = "02,72..."

In the first example desired integer digit count equals 2 as entered in inIntegerDigitCount, so the filter attaches character in inTrailingCharacter (zero) at the beginning of the result outString. Decimal mark is set as a comma and the number of fractional digits as 2.
The result string ends with ellipsis defined in inSuffix and the result is "02,72...".
Note that the second digit was rounded up to "2" due to the succeeding digit.

inDouble = 77
inIntegerDigitCount = 1
inFractionalDigitCount = 1
inDecimalMark = "."
inTrailingCharacter = "#"
inForceSignPrinting = True
inSuffix = "°"
outString = "+77.0°"

The second example demonstrates formatting with one integer digit and one fractional. Note that the integer part of the formatted number is less than the value, but it doesn't affect to this part (unlike fractional part which can cuts off excessing digits).
Trailing character (#) doesn't affect to anything, because desired integer digit count described by inIntegerDigitCount is one (the same effect would be for zero).


If you want to cut off excessing digits from a fractional part of a number (instead of rounding them), you can format a number with one extra precision digit and then use Substring to cut off the last digit. You can add a suffix manually by using ConcatenateStrings.


This filter can throw an exception to report error. Read how to deal with errors in Error Handling.

List of possible exceptions:

Error type Description
DomainError inDecimalMark has to be a single character in FormatDoubleToString.
DomainError inTrailingCharacter has to be a single character in FormatDoubleToString.

Complexity Level

This filter is available on Basic Complexity Level.

See Also

  • FormatString – Creates a string according to the given format and data.