JavaScript常用字符串与数组扩展函数小结_基础知识

String对象的扩展函数：

String.prototype.trim = function() { 
  return this.replace(/^\s+|\s+$/g,""); 
} 
String.prototype.ltrim = function() { 
  return this.replace(/^\s+/g,""); 
} 
String.prototype.rtrim = function() { 
  return this.replace(/\s+$/g,""); 
} 
String.prototype.splitAndTrim = function($delimiter, $limit) 
{ 
  var $ss = this.split($delimiter, $limit); 
  for(var $i=0; $i/g,'>'); 
} 
String.prototype.stripTags = function () { 
  return this.replace(/]+)>/g,''); 
} 
String.prototype.toArray = function() { 
  return this.split(''); 
} 
String.prototype.toIntArray = function() { 
  var returnArray = []; 
  for (var i=0; i<this.length i returnarray.push return returnarray string.prototype.replaceall="function($old," this.replace regexp></this.length>

变量替换

var a = "I Love {0}, and You Love {1},Where are {0}!";a.format("You","Me"); 
String.prototype.format = function(){ 
  var args = arguments; 
  return this.replace(/\{(\d+)\}/g,function(m,i,o,n){ 
    return args[i]; 
  }); 
} 

在字符串末尾追加字符串 

String.prototype.append = function($str){ 
  return this.concat($str); 
} 

删除指定索引位置的字符，索引无效将不删除任何字符 

String.prototype.deleteCharAt = function($sIndex){ 
  if($sIndex=this.length){ 
    return this.valueOf(); 
  }else if($sIndex==0){ 
    return this.substring(1,this.length); 
  }else if($sIndex==this.length-1){ 
    return this.substring(0,this.length-1); 
  }else{ 
    return this.substring(0,$sIndex)+this.substring($sIndex+1); 
  } 
} 

删除指定索引间的字符串.$sIndex和$eIndex所在的字符不被删除！依赖deleteCharAt  

String.prototype.deleteString = function($sIndex, $eIndex){ 
  if($sIndex==$eIndex){ 
    return this.deleteCharAt($sIndex); 
  }else{ 
    if($sIndex>$eIndex){ 
      var tIndex=$eIndex; 
      $eIndex=$sIndex; 
      $sIndex=tIndex; 
    } 
    if($sIndexthis.length-1)$eIndex=this.length-1; 
    return this.substring(0,$sIndex+1)+this.substring($eIndex,this.length); 
  } 
} 

检查字符串是否以某个字符串(str)结尾 

String.prototype.endsWith = function($str){ 
  return this.substr(this.length - $str.length) == $str; 
} 

检查该字符串是否以某个字符串开始 

String.prototype.startsWith = function(str){ 
  return this.substr(0, str.length) == str; 
}  

比较两个字符串是否相等，不区分大小写! 

String.prototype.equalsIgnoreCase = function($str){ 
  if(this.length!=$str.length){ 
    return false; 
  }else{ 
    var tmp1=this.toLowerCase(); 
    var tmp2=$str.toLowerCase(); 
    return tmp1==tmp2; 
  } 
} 

将指定的字符串插入到指定的位置后面!索引无效将直接追加到字符串的末尾 

String.prototype.insert = function($ofset, $str){ 
  if($ofset=this.length-1){ 
    return this.concat($str); 
  } 
  return this.substring(0,$ofset)+$str+this.substring($ofset+1); 
} 

将指定的位置的字符设置为另外指定的字符或字符串.索引无效将直接返回不做任何处理！  

String.prototype.setCharAt = function($ofset, $str){ 
  if($ofset=this.length-1){ 
    return this.valueOf(); 
  } 
  return this.substring(0,$ofset)+$str+this.substring($ofset+1); 
} 
String.prototype.replaceLen = function(start, len, replaced) {  
  if(!len)  
    return this;  
 
  if(start >= this.length)  
    return this;  
 
  var returnSeg = '';  
  var returnSeg2 = '';  
  var i = 0;  
  for (; i = start + len)  
      returnSeg2 += c;  
  }  
 
  return returnSeg + replaced + returnSeg2;  
} 

扩展基础类： 
替换字符，这个在替换填入比较有用，比如***天***小时 替换为 天小时  
 

String.prototype.replaceChar = function(target, replaced, start) {  
  if(!target)  
    return this;  
  if(!start)  
    start = 0;  
 
  var returnVal = this.substring(0, start);  
  var index = 0;  
  for (var i = start; i 

将该字符串反序排列 

String.prototype.reverse = function(){ 
  var str=""; 
  for(var i=this.length-1;i>=0;i--){ 
    str=str.concat(this.charAt(i)); 
  } 
  return str; 
} 

计算长度，每个汉字占两个长度，英文字符每个占一个长度 

String.prototype.ucLength = function(){ 
  var len = 0; 
  for(var i=0;i<this.length if>255)len+=2; 
    else len++; 
  } 
  return len; 
} 
</this.length>

在字符串的左边填充一些特定的字符 

String.prototype.lpad = function(len, s) { 
  var a = new Array(this); 
  var n = (len - this.length); 
  for ( var i = 0; i 

在字符串的右边填充一些特定的字符 

String.prototype.rpad = function(len, s) { 
  var a = new Array(this); 
  var n = (len - this.length); 
  for ( var i = 0; i 

把字符串的首字母转化为大写 

String.prototype.ucwords = function() { 
  return this.substring(0,1).toUpperCase().concat(this.substring(1)); 
} 
String.prototype.contains = function($str) { 
  return this.indexOf($str) > -1 ? true : false; 
} 

将格式为2008-04-02 10:08:44的字符串转成日期(String对象的值必须为: 2008-04-02 10:08:44) 

String.prototype.toDate = function(){ 
  var str = this.replace(/-/g,"/"); 
  return (new Date(str)); 
} 

将原来用字符串表示的十进数转成十进制浮点数: precision为精度 

String.prototype.toFloat = function(precision){ 
  precision = precision || 2; 
  return parseFloat(this,10).toFixed(precision); 
} 

将原来用字符串表示的十进数转成十进制整数 

String.prototype.toInt = function(){ 
  return parseInt(this,10).toString(); 
} 

将两个原来用字符串表示的十进数相加后当作字串返回 : addend为加数 

String.prototype.add = function(addend){ 
  var sum = parseFloat(this,10) + parseFloat(addend,10); 
  return sum+""; 
} 

十进制转其他进制代码如下nextScale为进制 如2,8,16 

String.prototype.shiftScale = function(nextScale){ 
  return parseFloat(this).toString(nextScale); 
} 

各进制互相转换 ：
this对象必须是整数
@param preScale 原是是几进制数
@param nextScale  要转换成几进制数 
 

String.prototype.scaleShift = function(preScale,nextScale){ 
  return parseInt(this,preScale).toString(nextScale); 
} 

全角2半角 document.write("ＡＢＣ　１２３，我们都是好朋友"); 
String.prototype.dbc2sbc = function (){ 
    return this.replace(/[\uff01-\uff5e]/g,function(a){return String.fromCharCode(a.charCodeAt(0)-65248);}).replace(/\u3000/g," "); 
} 

Array扩展函数：

var isNumeric = function(x) { 
  // returns true if x is numeric and false if it is not. 
  var RegExp = /^(-)?(\d*)(\.?)(\d*)$/;  
  return String(x).match(RegExp); 
} 
var myArray = [1,'two',3,'four',5,'six',7,'eight',9,'ten']; 
var oddArray=myArray.filter(isNumeric); // outputs: 1,3,5,7,9 
var oddArray=myArray.some(isNumeric); // outputs: true 
var oddArray=myArray.every(isNumeric); // outputs: false 
var printArray =function(x, idx){ 
  document.writeln('['+idx+'] = '+x); 
} 
myArray.forEach(printArray);// outputs: [0] = 1 [1] = two [2] = 3 [3] = four [4] = 5 
myArray.remove(9); 
document.writeln(myArray);  
 
if (!Array.prototype.every)  
{ 
 Array.prototype.every = function(fun /*, thisp*/) 
 { 
  var len = this.length; 
  if (typeof fun != "function") 
   throw new TypeError(); 
 
  var thisp = arguments[1]; 
  for (var i = 0; i  
Array.prototype.find = function(searchStr) { 
 var returnArray = false; 
 for (i=0; i<this.length i if returnarray="[]" returnarray.push else return></this.length>

随机改变数组的排序 

Array.prototype.shuffle = function (){   
  for(var rnd, tmp, i=this.length; i; rnd=parseInt(Math.random()*i), tmp=this[--i], this[i]=this[rnd], this[rnd]=tmp);  
  return this; 
}   
<!--var myArray = [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15]; 
var yourArray = [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15]; 
document.writeln(myArray.compare(yourArray)); // outputs: true;--> 
Array.prototype.compare = function(testArr) { 
  if (this.length != testArr.length) return false; 
  for (var i = 0; i 

去掉数组中重复的值var a = new Array("5","7","7"); a.unique(); 

Array.prototype.unique = function() { 
  var data = this || []; 
  var a = {}; //声明一个对象，javascript的对象可以当哈希表用 
  for (var i = 0; i = len) 
    from = len - 1; 
  } 
 
  for (; from > -1; from--) 
  { 
   if (from in this && 
     this[from] === elt) 
    return from; 
  } 
  return -1; 
 }; 
} 
Array.prototype.insertAt = function($value, $index) 
{ 
  if($index = this.length) 
    this.push($value); 
  else 
    this.splice($index, 0, $value); 
} 

根据数组的下标来删除元素  
 

Array.prototype.removeByIndex=function($n) {　  
  if($n

依赖indexOf  

Array.prototype.remove = function($value) 
{ 
  var $index = this.indexOf($value); 
 
  if($index != -1) 
    this.splice($index, 1); 
} 
 
Array.prototype.removeAll = function() 
{ 
  while(this.length > 0) 
    this.pop(); 
} 
 
Array.prototype.replace = function($oldValue, $newValue) 
{ 
  for(var $i=0; $i<this.length if this return array.prototype.swap="function($a," var array.prototype.max="function()" math.max.apply array.prototype.min="function()" math.min.apply array.prototype.splice="function(start," dellen item len="this.length;" start="start<0?0:start">len?len:start?start:0; 
  delLen=delLenlen?len:delLen?delLen:len;   
   
  var arr =[],res=[]; 
  var iarr=0,ires=0,i=0; 
   
  for(i=0;i<len if ires>=delLen)  arr[iarr++]=this[i]; 
    else { 
      res[ires++]=this[i]; 
      if(item&&ires==delLen){ 
        arr[iarr++]=item; 
      } 
    }   
  } 
  if(item&&ires<dellen arr for i="0;i<arr.length;i++){" this this.length="arr.length;" return res array.prototype.shift="function(){" if this.splice></dellen></len></this.length>

 
分开添加,关键字shallow copy,如果遇到数组，复制数组中的元素 

Array.prototype.concat = function(){ 
  var i=0; 
  while(i<arguments.length if arguments not shallow copy below array.prototype.concat.apply var j="0;" while this.splice i else this return array.prototype.join="function(separator){" str array.prototype.pop="function()" array.prototype.push="function(){" array.prototype.splice.apply this.length array.prototype.reverse="function(){" for temp="this[i];" array.prototype.slice="function(start," end len="this.length;" start="start<0?start+=len:start?start:0;">len?len:end?end:len; 
       
  var i=start; 
  var res = []; 
  while(i<end res.push return res array.prototype.unshift="function(){" array.prototype.splice.apply></end></arguments.length>

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