JavaScript中实现sprintf、printf函数
在JavaScript下实现大多数语言中都有的sprintf/printf函数功能。
http://www.webtoolkit.info/javascript-sprintf.html:比较完整的模拟sprintf函数功能。可用的格式化通配符：
1.%%-返回百分号本身
2.%b-二进制数字
3.%c-ASCII对应的字符
4.%d-整数
5.%f-浮点数
6.%o-八进制数字
7.%s-字符串
8.%x-16进制数字(小写字母形式)
9.%X-16进制数字(大写字母形式)
在%号和通配字符之间可用的选项包括(比如%.2f)：
1.+ (强制在数字前面显示+和-符号作为正负数标记。缺省情况下只有负数才显示-符号)
2.- (变量左对齐)
3.0 (使用0作为右对齐的填充字符)
4.[0-9] (设置变量的最小宽度)
5..[0-9](设置浮点数精度或字符串的长度)
/** * * Javascriptsprintf * http://www.webtoolkit.info/ * * **/
sprintfWrapper={
init:function(){
if(typeofarguments=="undefined"){returnnull;} if(arguments.length<1){returnnull;} if(typeofarguments[0]!="string"){returnnull;} if(typeofRegExp=="undefined"){returnnull;}
varstring=arguments[0]; varexp=newRegExp(/(%([%]|(\-)?(\+|\x20)?(0)?(\d+)?(\.(\d)?)?([bcdfosxX])))/g); varmatches=newArray(); varstrings=newArray(); varconvCount=0; varstringPosStart=0; varstringPosEnd=0; varmatchPosEnd=0; varnewString=''; varmatch=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){returnstring;} if((arguments.length-1)<convCount){returnnull;}
varcode=null; varmatch=null; vari=null;
for(i=0;i<matches.length;i++){
if(matches[i].code=='%'){substitution='%'} elseif(matches[i].code=='b'){ matches[i].argument=String(Math.abs(parseInt(matches[i].argument)).toString(2)); substitution=sprintfWrapper.convert(matches[i],true); } elseif(matches[i].code=='c'){ matches[i].argument=String(String.fromCharCode(parseInt(Math.abs(parseInt(matches[i].argument))))); substitution=sprintfWrapper.convert(matches[i],true); } elseif(matches[i].code=='d'){ matches[i].argument=String(Math.abs(parseInt(matches[i].argument))); substitution=sprintfWrapper.convert(matches[i]); } elseif(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]); } elseif(matches[i].code=='o'){ matches[i].argument=String(Math.abs(parseInt(matches[i].argument)).toString(8)); substitution=sprintfWrapper.convert(matches[i]); } elseif(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); } elseif(matches[i].code=='x'){ matches[i].argument=String(Math.abs(parseInt(matches[i].argument)).toString(16)); substitution=sprintfWrapper.convert(matches[i]); } elseif(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];
returnnewString;
},
convert:function(match,nosign){ if(nosign){ match.sign=''; }else{ match.sign=match.negative?'-':match.sign; } varl=match.min-match.argument.length+1-match.sign.length; varpad=newArray(l<0?0:l).join(match.pad); if(!match.left){ if(match.pad=="0"||nosign){ returnmatch.sign+pad+match.argument; }else{ returnpad+match.sign+match.argument; } }else{ if(match.pad=="0"||nosign){ returnmatch.sign+match.argument+pad.replace(/0/g,''); }else{ returnmatch.sign+match.argument+pad; } } } }
sprintf=sprintfWrapper.init;