Summary of common JavaScript strings and array extended functions _ basic knowledge

This article mainly introduces some common JavaScript strings and Array Extension functions, and sorts out some simple and frequently-used String and Array functions. For more information, see Extended functions of String objects:

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 <$ ss. length; $ I ++) $ ss [$ I] = $ ss [$ I]. trim (); return $ ss;} String.prototype.html Entities = function () {return this. replace (// g ,'&'). replace (//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
 
  

  
Variable replacement
  

  
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];   }); } 
  

  
Append a string to the end of the string

  

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

  
Delete the character at the specified index location. If the index is invalid, no characters will be deleted.

  

  
String.prototype.deleteCharAt = function($sIndex){   if($sIndex<0 || $sIndex>=this.length){     return this.valueOf();   }else if($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);   } } 
  

  
Deleting the strings. $ sIndex and $ eIndex between specified indexes is not deleted! Dependency deleteCharAt

  

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

  
Check whether the string ends with a string (str)

  

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

  
Check whether the string starts with a certain string

  

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

  
Compare the two strings to see if they are equal, case insensitive!

  

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

  
Insert the specified string to the end of the specified position! If the index is invalid, it will be appended to the end of the string.

  

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

  
Set the character at the specified position to another character or string. If the index is invalid, the system will return the result without any processing!

  

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

  
Extended basic class:
Replace the character, which is useful when you replace it with. For example, replace itDaysHours
  

  

  
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 < this.length; i++) {      var c = this.charAt(i);      target = typeof target == 'function' ? target.call(this, index) : target;      if (c == target) {        returnVal += typeof replaced == 'function' ? replaced.call(this, index) : replaced;        while (i < this.length - 1 && this.charAt(i + 1) == c) {          i++;        }        index++;      }else{        returnVal += c;      }    }     return returnVal;  }  
  

  
Sort this string in reverse order

  

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

  
Calculates the length. Each Chinese Character occupies two lengths, and each English character occupies one length.

  

  
String.prototype.ucLength = function(){   var len = 0;   for(var i=0;i
   
    255)len+=2;     else len++;   }   return len; } 
   
  

  
Fill in some specific characters on the left of the string

  

  
String.prototype.lpad = function(len, s) {   var a = new Array(this);   var n = (len - this.length);   for ( var i = 0; i < n; i++) {     a.unshift(s);   }   return a.join(""); } 
  

  
Fill in some specific characters on the right of the string

  

  
String.prototype.rpad = function(len, s) {   var a = new Array(this);   var n = (len - this.length);   for ( var i = 0; i < n; i++) {     a.push(s);   }   return a.join(""); } 
  

  
Converts the first letter of a string to uppercase.

  

  
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; } 
  

  
Convert a String in the format of 10:08:44 to a date (the value of the String object must be: 10:08:44)

  

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

  
Convert the decimal number represented by a string into a decimal floating point number: precision

  

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

  
Convert the decimal number represented by a string to a decimal integer.

  

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

  
Add two decimal numbers represented in the original string and return the result as a string: addend is the addition number.

  

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

  
The code for converting decimal to other hexadecimal formats is as follows: nextScale is in hexadecimal format, for example, 16.

  

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

  

Convert each other in hexadecimal notation:
This object must be an integer
@ Param preScale is a number in hexadecimal notation.
@ Param nextScale: Convert the data to a number in hexadecimal notation.
 

  

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

  
Fullwidth 2 halfwidth document. write ("ABC 123, we are all good friends ");
String. prototype. dbc2sbc = function (){
Return this. replace (/[\ uff01-\ uff5e]/g, function (a) {return String. fromCharCode (. charCodeAt (0)-65248 );}). replace (/\ u3000/g ,"");
}
  

Array extended functions:

  

  
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 <len; I ++) {if (I in this &&! Fun. call (thisp, this [I], I, this) return false;} return true ;}}if (! Array. prototype. filter) {Array. prototype. filter = function (fun/*, thisp */) {var len = this. length; if (typeof fun! = "Function") throw new TypeError (); var res = new Array (); var thisp = arguments [1]; for (var I = 0; I <len; I ++) {if (I in this) {var val = this [I]; // in case fun mutates this if (fun. call (thisp, val, I, this) res. push (val) ;}} return res ;};} if (! Array. prototype. forEach) {Array. prototype. forEach = function (fun/*, thisp */) {var len = this. length; if (typeof fun! = "Function") throw new TypeError (); var thisp = arguments [1]; for (var I = 0; I <len; I ++) {if (I in this) fun. call (thisp, this [I], I, this) ;}}}if (! Array. prototype. map) {Array. prototype. map = function (fun/*, thisp */) {var len = this. length; if (typeof fun! = "Function") throw new TypeError (); var res = new Array (len); var thisp = arguments [1]; for (var I = 0; I <len; I ++) {if (I in this) res [I] = fun. call (thisp, this [I], I, this) ;}return res ;}}if (! Array. prototype. some) {Array. prototype. some = function (fun/*, thisp */) {var len = this. length; if (typeof fun! = "Function") throw new TypeError (); var thisp = arguments [1]; for (var I = 0; I <len; I ++) {if (I in this & fun. call (thisp, this [I], I, this) return true ;}return false ;}} Array. prototype. sortNum = function () {return this. sort (function (a, B) {return a-B ;});}
   Array. prototype. find = function (searchStr) {var returnArray = false; for (I = 0; I
   
    

    
Randomly changing the sorting of Arrays

    

    
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; }   
      Array.prototype.compare = function(testArr) {   if (this.length != testArr.length) return false;   for (var i = 0; i < testArr.length; i++) {     if (this[i].compare) {        if (!this[i].compare(testArr[i])) return false;     }     if (this[i] !== testArr[i]) return false;   }   return true; } 
    

    
Remove the repeated values var a = new Array ("5", "7", "7"); a. unique ();

    

    
Array. prototype. unique = function () {var data = this | []; var a = {}; // declare an object, javascript objects can use for (var I = 0; I <data. length; I ++) {a [data [I] = true; // set the flag to use the value of the array as the subscript, so that duplicate values can be removed} data. length = 0; for (var I in a) {// traverses the object and restores the marked object to the array this [data. length] = I;} return data;} Array. prototype. addAll = function ($ array) {if ($ array = null | $ array. length = 0) return; for (var $ I = 0; $ I <$ array. length; $ I ++) this. push ($ array [$ I]);} Array. prototype. contains = function ($ value) {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 <0) this. unshift ($ value); else if ($ index> = this. length) this. push ($ value); else this. splice ($ index, 0, $ value );}
     
    

    

Deletes an element based on the subscript of the array.
  

    

    
Array. prototype. removeByIndex = function ($ n) {if ($ n <0) {// if n <0, no operation is performed. Return this;} else {return this. slice (0, $ n). concat (this. slice ($ n + 1, this. length ));}}
    

    
Dependent on 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
     
      
Len? Len: start? Start: 0; delLen = delLen <0? 0: delLen> len? Len: delLen? DelLen: len; var arr = [], res = []; var iarr = 0, ires = 0, I = 0; for (I = 0; I
      
       
= DelLen) arr [iarr ++] = this [I]; else {res [ires ++] = this [I]; if (item & ires = delLen) {arr [iarr ++] = item ;}} if (item & ires
       
        
  
Added separately. The key word is shallow copy. If an array is encountered, copy the elements in the array.

        

        
Array.prototype.concat = function(){   var i=0;   while(ilen?len:end?end:len;          var i=start;   var res = [];   while(i