Number.format(decimalsN[,widthN][,padStr])

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Number.format(decimalsN[,widthN][,padstr])

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 allowed for.

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

For example, if $MyNumber is 3.1415927, then

$MyString = $MyNumber.format(2); is "3.14"

$MyString = $MyNumber.format(0); is "3"

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

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

$MyString = $MyNumber.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:

$MyString = 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:

$MyString = (5.1415927).format(2); is "5.14"

$MyString = (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 $MaxLenNumber 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:

$MaxLenNumber = ($MySizeList.nsort).at(-); 

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:

$MyString = 7.format(0,3); gives " 7"

$MyString = 7.format(0,3,"0"); gives "007"

$MyString = 7.format(0,3,"#"); gives "##7"

Number.format("formatString")

An alternate usage is to supply a quoted formatString. Currently only one such string is supported: "l" (lowercase letter '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. For example, if $MyNumber is 4562781.4, and it is desired to display it as a string with thousands delimited:

$MyString = $MyNumber.format("l"); gives "4,562,781.4"

Of course, depending on the users local, the delimiter may be something else. For instance in a German locale setting, it would be "4.562.781,4". For more on such difference see Wikipedia's article on 'Decimal Separators'.