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 Function   [other Function type actions]

 Item   [operators of similar scope]

 Formatting   [other Formatting operators]




Returns Number as a String, formatted to decimalsN decimal places.

If widthN is supplied, Number returned additionally left padded with spaces so that widthN equals the sum of: [padding spaces]+[minus sign]+integer number(s)+decimal point+[decimal numbers]. Note that with widthN, decimal character is not counted as part of the number. The presence of a minus sign is

For example, if $MyNum is 3.1415927, then

$MyNum.format(2) is 3.14

$MyNum.format(0) is 3

$MyNum.format(2,7) is "   3.14" (3 left padding spaces + 1 integer number + decimal point + 3 decimal numbers = 7)

But if $MyNum is negative, e.g. -3.1415927, then

$MyNum.format(2,7) is "  -3.14" (2 left padding spaces + minus sign + 1 integer number + decimal point + 3 decimal numbers = 7)

Literal numbers, e.g. 3.1415927, can also be worked with:

5.1415927.format(2) is 5.14

The above works but the following syntax may seem less ambiguous by using parentheses to delimit the literal number:

(5.1415927).format(2) is 5.14

(5.1415927).format(1,5) is '  5.1' (two left padding spaces + 1 integer number + decimal point + 1 decimal number = 5)

If a group of numbers are being formatted so as to vertically decimal-point align as a column figures, e.g. financial data, it is necessary to know the widthN of 'longest' number to be used, remembering that a negative number adds one to its width count; 45 is width 2, -45 is width 3. In the example below the longest (widthN) number in a set of currency figures has been worked out stored in a user Number attribute $MaxNumLen. Being currency, 2 decimal places will be enforced, and each number can be evaluated by a common formatting:

[the number].format(2,$MaxLenNum) 

If the widthN for a set of numbers cannot easily be assessed, an alternate option is simply to use a number known to be bigger than all likely width valid. Thus every number, including the longest gets left-padded - but all end up correctly aligned. In the latter example if all numbers are always likely to be less than 20, then $MaxLenNum could be set to 20, or simply used directly:

[the number].format(2,$MaxLenNum) 

There is no easy way to sort a list of numbers on size (i.e. their widthN), other than by looping the list via List.each() transforming each to a string (using zero decimal places!), saving the String.size of each of these as a number in a new list, then List.nsort() and take the last item, .at(-1). As .nsort() sorts on ascending numerical order, the latter will be the size of the longest string (including negative numbers) in the original list. Assuming $MySizeList has all the size strings:

$MaxLenNum = ($MySizeList.nsort).at(-1) 

Why leave out decimal places when coercing the numbers to strings? 1234.56 is a bigger number than 12.34567, but the latter is the bigger size. However, 1234 is both bigger and 'wider' than 12.

As can be seen, just setting a large arbitrary widthN might save a lot of messing about!

If the optional padStr is given, this specifies the character used for padding. The default is a space:

7.format(0,3) gives " 7"

7.format(0,3,"0") gives "007"

7.format(0,3,"#") gives "##7"


An alternate usage is to supply a quoted formatString. Currently only one such string is supported: "L". This will return a string of the number formatted with (OS) locale-dependent group & decimal delimiters. For example, for the US locale these are a comma and a period; in other locales they may vary.

This function supplements the existing format() and Number.precision() functions.

A Tinderbox Reference File : Actions & Rules : Operators : Full Operator List : Number.format(decimalsN[,widthN][,padStr])