printf()-like Format Function in VBScript

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Overview

The function fmt helps you to format a string in VBScript as you do in C.

In C, if you write:

printf( "this is %s number %d", "test", 1 );

then you would use the function fmt in VBScript like this:

dim str
str = fmt( "this is %x number %x", Array("test", 1) )

Details

The complete function looks like this:

' works like the printf-function in C.
' takes a string with format characters and an array
' to expand.
'
' the format characters are always "%x", independ of the
' type.
'
' usage example:
'	dim str
'	str = fmt( "hello, Mr. %x, today's date is %x.", Array("Miller",Date) )
'	response.Write str
function fmt( str, args )
	dim res		' the result string.
	res = ""

	dim pos		' the current position in the args array.
	pos = 0

	dim i
	for i = 1 to Len(str)
		' found a fmt char.
		if Mid(str,i,1)="%" then
			if i<Len(str) then
				' normal percent.
				if Mid(str,i+1,1)="%" then
					res = res & "%"
					i = i + 1

				' expand from array.
				elseif Mid(str,i+1,1)="x" then
					res = res & CStr(args(pos))
					pos = pos+1
					i = i + 1
				end if
			end if

		' found a normal char.
		else
			res = res & Mid(str,i,1)
		end if
	next

	fmt = res
end function

The format character is always %x, independent of the actual type, since VBScript has no direct types like integer or string.

Improve Me!

The function fits my needs where I used it, but can be extended in some ways to behave more like printf:

• Format characters can be extended, i.e., the %x could be divided up into %d for integers, %x for hex numbers, %f for float, etc. 
• The other printf features like leading zeros and all that stuff could be added too.

Epilog

As always: my tip for editing VBScript files: Tried a lot of editors (including Frontpage, InterDev, etc.), I found the most usable program is EditPlus, which you can find on www.editplus.com (no, I'm not getting money from them).

Please feel free to ask any questions you have by e-mail: keim@zeta-software.de.

History

• 20^th January, 2000: Initial post