在JavaScript 下實現大多數語言中都有的sprintf / printf 函數功能。
http://www.webtoolkit.info/javascript-sprintf.html : 比較完整的模擬sprintf函數功能。可用的格式化通配符：
1.%% - 返回百分號本身
2.%b - 二進制數字
3.%c - ASCII對應的字符
4.%d - 整數
5.%f - 浮點數
6.%o - 八進制數字
7.%s - 字符串
8.%x - 16進制數字(小寫字母形式)
9.%X - 16進制數字(大寫字母形式)
在% 號和通配字符之間可用的選項包括(比如%.2f)：
1.+ (強制在數字前面顯示+ 和- 符號作為正負數標記。缺省情況下只有負數才顯示- 符號)
2.- (變量左對齊)
3.0 (使用0作為右對齊的填充字符)
4.[0-9] (設置變量的最小寬度)
5..[0-9] (設置浮點數精度或字符串的長度)
複製代碼代碼如下:
/**
*
* 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,
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(matches[i].argument)))));
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;
如果只是想進行簡單的位置變量內容替換而不需要額外的格式化處理的話，可以用比較簡單的YUI tools 中所提供的printf：
複製代碼代碼如下:
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;
}
使用的時候像YAHOO.Tools.printf("顯示字符串{0} ， {1}。", "1", "2"); 這樣用{?}來做匹配。