Tcl/Tk in a Nutshell

Name

format

format formatString [arg...]

Format a string using ANSI sprintf( ) -style formatString and arguments. Returns the formatted string. The format string placeholders have the form:

%[argpos$] [flag] [width] [.prec] [h|l]char

where argpos, width, and prec are integers and possible values for char are as follows:

d	Signed integer	u	Unsigned integer
i	Signed integer (n, 0n, or 0xn)	o	Unsigned octal
x	Unsigned hex	X	Unsigned HEX
c	Int to char	s	String
f	Float (fixed)	e	Float (0e0)
E	Float (0E0)	g	Auto float (f or e)
G	Auto float (F or E)	%	Percent sign

Possible values for flag are as follows:

-	Left justified	+	Always signed
0	Zero padding	space	Space padding
#	Alternate output format

Example

set i 12
   set j 1.2
   puts [format "%4d %5.3f" $i $j]
     12 1.200
   puts [format "%04X %5.3e" $i $j]
   000C 1.200e+00