JavaScript implements a simple Map sample introduction

  This article introduces the use of JavaScript to achieve a simple map, you can get the map, judge, delete, add, and so on, interested friends can understand the next

  Code as follows:/*  * Map object, realize map function   *  * Interface:  * size () Get the number of map elements   * IsEmpty () to determine if map is null   * CLE AR () Delete all elements of map   * PUT (key, value) to add element (key, value)   * Remove (key) to map to delete the element of the specified key, return true successfully, fail return false  * GE T (key) gets the element value value of the specified key, and the failure returns null  * Element (index) to get the element of the specified index (using Element.key,element.value to get key and value), Failure returns null   * ContainsKey (key) determines whether the map contains elements of the specified key   * Containsvalue (value) to determine if the map contains elements of the specified value   * VALUES () Gets the array (array)   * keys () of all the value in the map to get an array of all keys in the map (array)   *  * Example:  * var map = new map ();  *&nbsp ; * Map.put ("key", "value");  * var val = map.get ("key")   * ......  *  */  function map () {  this. elements = new Array ();   //Get the number of map elements   this.size = function () {  return this.elements.length; } ;   //Determine if map is empty   This.isempty = function () {  return (This.elements.length < 1); };  &N Bsp Delete all elements of map   This.clear = functIon () {  this.elements = new Array (); };   //add element (key, value)   This.put = function to map (_key, _ Value) {  This.elements.push ({  key: _key,  value: _value }); };   //delete the element of the specified key into Work returns TRUE, Failure returns false  This.removebykey = function (_key) {  var bln = false;  Try {  for (i = 0; i < th Is.elements.length; i++) {  if (This.elements[i].key = = _key {  this.elements.splice (i, 1);  return true; } }&nbsp ; catch (e) {  bln = false; }  return bln; };   //delete element of specified value, returns true successfully, failure returns false  T His.removebyvalue = function (_value) {//removebyvalueandkey  var bln = false;  Try {  for (i = 0; i < th Is.elements.length; i++) {  if (This.elements[i].value = = _value {  this.elements.splice (i, 1);  return true; } }& nbsp catch (e) {  bln = false; }  return bln; };   //delete element of specified value, successfulReturns TRUE, Failure returns false  This.removebyvalueandkey = function (_key,_value) {  var bln = false;  Try {  for (i = 0; i < this.elements.length; i++) {  if (This.elements[i].value = = _value && This.elements[i].key = _key) {  This.elements.splice (i , 1);  return true; } } } catch (e) {  bln = false; }  return bln; };  & nbsp Gets the element value value of the specified key, and the failure returns null  This.get = function (_key) {  try {  for (i = 0; i < this.elements.length i + +) {  if (This.elements[i].key = = _key) {  return this.elements[i].value; } } } catch (e) {&N Bsp Return false; }  return false; };   // Gets the element of the specified index (using Element.key,element.value to get key and value), and the failure returns null  this.element = function (_index) {  if (_index < 0 | | _index >= this.elements.length) {  return null; }  return this.elements[_index]; };   //Determine if the map contains the element   this for the specified key.ContainsKey = function (_key) {  var bln = false;  Try {  for (i = 0; i < this.elements.length; i++) {&NB Sp if (This.elements[i].key = = _key) {  bln = true; } } } catch (e) {  bln = false; }  return bln; };   //Determine if the map contains elements of the specified value   This.containsvalue = function (_value) {  var bln = FA lse;  try {  for (i = 0; i < this.elements.length i++) {  if (This.elements[i].value = _value) {  bln = true; } } } catch (e) {  bln = false; }  return bln; };   //Judge Ma P contains the element with the specified value   this.containsobj = function (_key,_value) {  var bln = false;  Try {  for (i = 0; I & Lt This.elements.length; i++) {  if (This.elements[i].value = = _value && This.elements[i].key = _key) {  bln = true; }&nbs P } } catch (e) {  bln = false; }  return bln; };   //Get an array of all the value in the map (array  this.values = function () {  var arr = new Array ();  for (i = 0; i < this.elements.length; i++) {&nbsp ; Arr.push (this.elements[i].value); }  return arr; };   //Get an array of all the value in the map (array)   This.valuesbykey = function (_key) {  var arr = new Array ();  for (i = 0; i < this.elements.length; i++) {&nbs P if (This.elements[i].key = = _key) {  arr.push (this.elements[i].value); } }  return arr; };& nbsp  //Get the Array (array)   This.keys = function () {  var arr = new Array ();  for all keys in the map (i = 0; i < THIS.E Lements.length; i++) {  Arr.push (this.elements[i].key); }  return arr; };   //Get key through value  This.keysbyvalue = function (_value) {  var arr = new Array ();  for (i = 0; i < this.elements.length; i++) {&N Bsp if (_value = this.elements[i].value) {  arr.push (this.elements[i].key); } }  return arr; };    //Get the Array (array)   this.keysremoveduplicate = function () {  var arr = new Array ();  for all keys in the map (i = 0; i < This.elements.length; i++) {  var flag = true;  for (var j=0;j<arr.length;j++) {  if (arr[j] = = THIS.ELEMENTS[I].KEY) {  fla g = false;  break; } }  if (flag) {  Arr.push (this.elements[i].key); } }  return arr; }; }