详解JavaScript数组和字符串中去除重复值的方法
原理在代码中表现得非常清晰，我们直接来看代码例子：
varages=array.map(function(obj){returnobj.age;});
ages=ages.filter(function(v,i){returnages.indexOf(v)==i;});
console.log(ages);//=>[17,35]
functionisBigEnough(element){
returnelement>=10;
}
varfiltered=[12,5,8,130,44].filter(isBigEnough);
//filteredis[12,130,44]
functiononlyUnique(value,index,self){
returnself.indexOf(value)===index;
}
//usageexample:
vara=['a',1,'a',2,'1'];
varunique=a.filter(onlyUnique);//returns['a',1,2,'1']
比较好使的Function(不兼容IE7)
functionunique(array){
returnarray.filter(function(el,index,arr){
returnindex==arr.indexOf(el);
});
}
比较好使的Function(兼容IE7)
//去除数组中重复值
functiongetNoRepeat(s){
returns.sort().join(",,").replace(/(,|^)([^,]+)(,,\2)+(,|$)/g,"$1$2$4").replace(/,,+/g,",").replace(/,$/,"").split(",");
}
vararr=["北京","上海","天津","武汉","上海","天津","武汉","北京","上海","天津","武汉","天津","武汉","天津","武汉","天津","武汉",
"北京","上海","天津","武汉","上海","天津","武汉","北京","上海","天津","武汉","天津","武汉","天津","武汉","天津","武汉",
"北京","上海","天津","武汉","上海","天津","武汉","北京","上海","天津","武汉","天津","武汉","天津","武汉","天津","武汉"];
arr=getNoRepeat(arr);
alert(arr.length);//4
alert(arr.toString());//"北京","上海","天津","武汉"
利用map原理
vararr=["北京","上海","天津","武汉","上海","天津","武汉","北京","上海","天津","武汉","天津","武汉","天津","武汉","天津","武汉",
"北京","上海","天津","武汉","上海","天津","武汉","北京","上海","天津","武汉","天津","武汉","天津","武汉","天津","武汉",
"北京","上海","天津","武汉","上海","天津","武汉","北京","上海","天津","武汉","天津","武汉","天津","武汉","天津","武汉"];
varjson={};
for(vari=0;i<arr.length;i++){
json[arr[i]]=arr[i];
}
arr=newArray();
for(varkeyinjson){
arr.push(key);
}
alert(arr.toString());
//"北京","上海","天津","武汉"