_javascript techniques for implementing sprintf and printf functions in JavaScript

sprintf/printf functions in most languages are implemented in JavaScript.

Http://www.webtoolkit.info/javascript-sprintf.html: The complete simulation sprintf function function. Available formatting wildcard characters:
1.%%-Returns the percent sign itself
2.%B-Binary digits
3.%c-ascii the corresponding character
4.%d-Integer
5.%f-floating-point numbers
6.%o-Eight binary digits
7.%s-strings
8.%x-16 digits (lowercase letters)
9.%X-16 numbers (in uppercase)

The options available between the% and the wildcard characters include (for example,%.2f):

1.+ (Forces the + and-symbol to be shown as positive negative numbers before the number.) Only negative numbers appear by default-symbols)
2.-(left-aligned variable)
3.0 (use 0 as right-aligned padding character)
4.[0-9] (Sets the minimum width of the variable)
5..[0-9] (set floating-point precision or length of string)

Copy Code code as follows:

/**
*
* Javascript sprintf
* http://www.webtoolkit.info/
*
*
**/

Sprintfwrapper = {

Init:function () {

if (typeof arguments = = "undefined") {return null;}
if (Arguments.length < 1) {return null;}
if (typeof Arguments[0]!= "string") {return null;}
if (typeof RegExp = = "undefined") {return null;}

var string = Arguments[0];
var exp = new RegExp (/(%) ([%]| ( \-)? (\+|\x20)? (0)? (\d+)? (\. (\d)? ([bcdfosxx])) /g);
var matches = new Array ();
var strings = new Array ();
var convcount = 0;
var stringposstart = 0;
var stringposend = 0;
var matchposend = 0;
var newstring = ';
var match = null;

while (match = Exp.exec (string)) {
if (Match[9]) {convcount = 1;}

Stringposstart = Matchposend;
Stringposend = Exp.lastindex-match[0].length;
Strings[strings.length] = string.substring (Stringposstart, stringposend);

      matchposend = Exp.lastindex;
      Matches[matches.length] = {
        match : Match[0],
        left:match[3]? true:false,
    & nbsp;   Sign:match[4] | | ',
        pad:match[5] | | ',
        min:match[6] | | 0,
         Precision:match[8],
        code:match[9] | | '% ',
        negative:parseint (Arguments[convcount]) < 0 true:false,
        argument:string (Arguments[convcount])
      };
   }
    Strings[strings.length] = string.substring (matchposend);

if (Matches.length = = 0) {return string;}
if ((arguments.length-1) < Convcount) {return null;}

var code = NULL;
var match = null;
var i = null;

For (i=0 i<matches.length; i++) {

if (matches[i].code = = '% ') {substitution = '% '}
else if (Matches[i].code = = ' B ') {
Matches[i].argument = String (Math.Abs (parseint (matches[i].argument)). ToString (2));
substitution = Sprintfwrapper.convert (matches[i], true);
}
else if (Matches[i].code = = ' C ') {
Matches[i].argument = String (String.fromCharCode (parseint (Math.Abs (parseint))));
substitution = Sprintfwrapper.convert (matches[i], true);
}
else if (Matches[i].code = = ' d ') {
Matches[i].argument = String (Math.Abs (parseint (matches[i].argument)));
substitution = Sprintfwrapper.convert (matches[i]);
}
else if (Matches[i].code = = ' F ') {
Matches[i].argument = String (Math.Abs (parsefloat (matches[i].argument)). toFixed (matches[i].precision? matches[i). Precision:6));
substitution = Sprintfwrapper.convert (matches[i]);
}
else if (Matches[i].code = = ' O ') {
Matches[i].argument = String (Math.Abs (parseint (matches[i].argument)). ToString (8));
substitution = Sprintfwrapper.convert (matches[i]);
}
else if (Matches[i].code = = ' s ') {
matches[i].argument = matches[i].argument.substring (0, matches[i].precision? matches[i].precision:matches[i). Argument.length)
substitution = Sprintfwrapper.convert (matches[i], true);
}
else if (Matches[i].code = = ' x ') {
Matches[i].argument = String (Math.Abs (parseint (matches[i].argument)). ToString (16));
substitution = Sprintfwrapper.convert (matches[i]);
}
else if (Matches[i].code = = ' X ') {
Matches[i].argument = String (Math.Abs (parseint (matches[i].argument)). ToString (16));
substitution = Sprintfwrapper.convert (Matches[i]). toUpperCase ();
}
else {
substitution = Matches[i].match;
}

NewString + = Strings[i];
NewString + = substitution;

}
NewString + = Strings[i];

return newstring;

},

Convert:function (Match, nosign) {
if (nosign) {
Match.sign = ';
} else {
Match.sign = match.negative? '-': match.sign;
}
var L = match.min-match.argument.length + 1-match.sign.length;
var pad = new Array (L < 0 0:l). Join (Match.pad);
if (!match.left) {
if (Match.pad = = "0" | | nosign) {
return match.sign + pad + match.argument;
} else {
return pad + match.sign + match.argument;
}
} else {
if (Match.pad = = "0" | | nosign) {
Return match.sign + match.argument + pad.replace (/0/g, ' ");
} else {
Return match.sign + match.argument + pad;
}
}
}
}

sprintf = Sprintfwrapper.init;

If you just want to do a simple location variable content replacement without the need for additional formatting, you can use the simple YUI tools to provide the printf:

Copy Code code as follows:

YAHOO. tools.printf = function () {
var num = arguments.length;
var ostr = arguments[0];
for (var i = 1; i < num; i++) {
var pattern = "\\{" + (i-1) + "\}";
var re = new RegExp (Pattern, "G");
OSTR = Ostr.replace (Re, arguments[i]);
}
return ostr;
}

When used like YAHOO. Tools.printf ("display string {0}, {1}.") "," 1 "," 2 "); In this way, use the {?} To make a match.