如何在数组中获得唯一值的列表?我总是必须使用第二个数组，或者在JavaScript中有类似于java的hashmap的东西吗?
我将只使用JavaScript和jQuery。不能使用其他库。
当前回答
Array.prototype.unique = function () {
var dictionary = {};
var uniqueValues = [];
for (var i = 0; i < this.length; i++) {
if (dictionary[this[i]] == undefined){
dictionary[this[i]] = i;
uniqueValues.push(this[i]);
}
}
return uniqueValues;
}
其他回答
你只需要香草JS找到唯一的数组。some和Array.reduce。在ES2015语法中，它只有62个字符。
a.reduce((c, v) => b.some(w => w === v) ? c : c.concat(v)), b)
数组中。some和Array。IE9+和其他浏览器支持。只需要在不支持ES2015语法的浏览器中修改常规函数的胖箭头函数即可。
var a = [1,2,3];
var b = [4,5,6];
// .reduce can return a subset or superset
var uniques = a.reduce(function(c, v){
// .some stops on the first time the function returns true
return (b.some(function(w){ return w === v; }) ?
// if there's a match, return the array "c"
c :
// if there's no match, then add to the end and return the entire array
c.concat(v)}),
// the second param in .reduce is the starting variable. This is will be "c" the first time it runs.
b);
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/some https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/Reduce
我在想我们能不能用线性搜索来消除重复项
JavaScript:
function getUniqueRadios() {
var x=document.getElementById("QnA");
var ansArray = new Array();
var prev;
for (var i=0;i<x.length;i++)
{
// Check for unique radio button group
if (x.elements[i].type == "radio")
{
// For the first element prev will be null, hence push it into array and set the prev var.
if (prev == null)
{
prev = x.elements[i].name;
ansArray.push(x.elements[i].name);
} else {
// We will only push the next radio element if its not identical to previous.
if (prev != x.elements[i].name)
{
prev = x.elements[i].name;
ansArray.push(x.elements[i].name);
}
}
}
}
alert(ansArray);
}
HTML:
<body>
<form name="QnA" action="" method='post' ">
<input type="radio" name="g1" value="ANSTYPE1"> good </input>
<input type="radio" name="g1" value="ANSTYPE2"> avg </input>
<input type="radio" name="g2" value="ANSTYPE3"> Type1 </input>
<input type="radio" name="g2" value="ANSTYPE2"> Type2 </input>
<input type="submit" value='SUBMIT' onClick="javascript:getUniqueRadios()"></input>
</form>
</body>
既然我在@Rocket的回答的评论中谈到了它，我不妨提供一个不使用库的示例。这需要两个新的原型功能，包含和唯一
Array.prototype.contains =函数(v) { For (var I = 0;I < this.length;我+ +){ If (this[i] === v)返回true; ｝ 返回错误; }; Array.prototype.unique = function() { Var arr = []; For (var I = 0;I < this.length;我+ +){ If (!arr.contains(this[i])) { arr.push(这[我]); ｝ ｝ 返回arr; ｝ Var duplicate = [1,3,4,2,1,2,3,8]; Var uniques = duplicate .unique();// result = [1,3,4,2,8] console.log(独立);
为了获得更高的可靠性，您可以用MDN的indexOf shim替换contains，并检查每个元素的indexOf是否等于-1:documentation
使用第二阵列的短而甜的解决方案;
var axes2=[1,4,5,2,3,1,2,3,4,5,1,3,4];
var distinct_axes2=[];
for(var i=0;i<axes2.length;i++)
{
var str=axes2[i];
if(distinct_axes2.indexOf(str)==-1)
{
distinct_axes2.push(str);
}
}
console.log("distinct_axes2 : "+distinct_axes2); // distinct_axes2 : 1,4,5,2,3
Array.prototype.unique = function () {
var dictionary = {};
var uniqueValues = [];
for (var i = 0; i < this.length; i++) {
if (dictionary[this[i]] == undefined){
dictionary[this[i]] = i;
uniqueValues.push(this[i]);
}
}
return uniqueValues;
}
