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JavaScript中實(shí)現(xiàn)sprintf、printf函數(shù)

更新時(shí)間：2015年01月27日 09:51:03 投稿：junjie

這篇文章主要介紹了JavaScript中實(shí)現(xiàn)sprintf、printf函數(shù),這兩個(gè)函數(shù)在大多數(shù)編程語(yǔ)言中都有,但JS中卻沒(méi)有,本文介紹在js中實(shí)現(xiàn)這兩個(gè)函數(shù)功能,需要的朋友可以參考下

在 JavaScript 下實(shí)現(xiàn)大多數(shù)語(yǔ)言中都有的 sprintf / printf 函數(shù)功能。

http://www.webtoolkit.info/javascript-sprintf.html : 比較完整的模擬sprintf函數(shù)功能?？捎玫母袷交ㄅ浞?br /> 1.%% - 返回百分號(hào)本身
2.%b - 二進(jìn)制數(shù)字
3.%c - ASCII對(duì)應(yīng)的字符
4.%d - 整數(shù)
5.%f - 浮點(diǎn)數(shù)
6.%o - 八進(jìn)制數(shù)字
7.%s - 字符串
8.%x - 16進(jìn)制數(shù)字 (小寫(xiě)字母形式)
9.%X - 16進(jìn)制數(shù)字 (大寫(xiě)字母形式)

在 % 號(hào)和通配字符之間可用的選項(xiàng)包括 (比如 %.2f)：

1.+      (強(qiáng)制在數(shù)字前面顯示 + 和 - 符號(hào)作為正負(fù)數(shù)標(biāo)記。缺省情況下只有負(fù)數(shù)才顯示 - 符號(hào))
2.-      (變量左對(duì)齊)
3.0      (使用0作為右對(duì)齊的填充字符)
4.[0-9] (設(shè)置變量的最小寬度)
5..[0-9] (設(shè)置浮點(diǎn)數(shù)精度或字符串的長(zhǎng)度)

復(fù)制代碼代碼如下:

/**
*
* 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(jìn)行簡(jiǎn)單的位置變量?jī)?nèi)容替換而不需要額外的格式化處理的話，可以用比較簡(jiǎn)單的 YUI tools 中所提供的printf：

復(fù)制代碼代碼如下:

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(shí)候像 YAHOO.Tools.printf("顯示字符串 {0} ， {1}。", "1", "2"); 這樣用{?}來(lái)做匹配。