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hash散列中需要确定key和value的唯一确定关系。

hash散列便于快速的插入删除和修改，不便于查找最大值等其他操作

以下为字符和数字的hash散列：

function HashTable () {this.table = new Array(137);this.value = new Array();this.simpleHash = simpleHash;this.betterHash = betterHash;this.display = display;this.put = put;this.get = get;this.buildChains = buildChains; // 开链法解决碰撞
}function simpleHash (data) {var total = 0;for(var i =0; i<data.length; i++){total= total + data.charCodeAt(i);}return total % this.table.length;
}function betterHash (data) {var total = 0;const h = 37; // 挑选合适的质数data = data.toString();for(var i=0;i<data.length; i++){total = total*h + data.charCodeAt(i);}total = total % this.table.length;if(total<0) {return total+=this.table.length-1;}return parseInt(total);
}function put (key, value) {var pos = this.betterHash(key);if(this.table[pos] === undefined){this.table[pos] = key;this.value[pos] = value;}else{while(this.table[pos]!==undefined){pos++}this.table[pos] = key;this.value[pos] = value;}
}function get(key) {var hash = -1;hash = this.betterHash(key);if (hash > -1) {for (var i = hash; this.table[hash] != undefined; i++) {if (this.table[hash] == key) {return this.value[hash];}}}return undefined;
}function display () {var _this = this;this.value.forEach(function(item, index){if (item!==undefined) {console.log(_this.table[index] + ": " + item);}})
}function buildChains () {this.table.forEach(function (item, index) {item = new Array();})
}

hash的使用方法：

function buildChains () {this.table.forEach(function (item, index) {item = new Array();})
}var someNames = ["David", "Jennifer", "Donnie", "Raymond","Cynthia", "Mike", "Clayton", "Danny", "Jonathan", "Donnie"];var hs = new HashTable();
someNames.forEach(function(item, index){hs.put(item, item + "Val")
})
hs.display();console.log(hs.get("David"))