Javascript - 重新索引数组
声明：本页面是StackOverFlow热门问题的中英对照翻译，遵循CC BY-SA 4.0协议，如果您需要使用它，必须同样遵循CC BY-SA许可，注明原文地址和作者信息，同时你必须将它归于原作者（不是我）：StackOverFlow
原文地址: http://stackoverflow.com/questions/4759745/
Warning: these are provided under cc-by-sa 4.0 license. You are free to use/share it, But you must attribute it to the original authors (not me):
StackOverFlow
Javascript - Reindexing an array
提问by borayeris
Hereis my example. Can you tell me how can I make the array have consecutive keys
这是我的例子。你能告诉我如何让数组有连续的键吗
array[0]
array[1]
array[2]
when I have
当我有
var testArray = new Array();
testArray[3]="qwerty";
testArray[7]="asdfgh";
testArray[13]="zxcvbn";
var testString = testArray.join();
Editor's note:The asker wants to reindex his array.
编者按：提问者想要重新索引他的数组。
采纳答案by Exelian
If you don't mind using javascript 1.6: (note: this code uses the jQUery library)
如果您不介意使用 javascript 1.6：（注意：此代码使用 jQUEry 库）
var testArray = new Array();
testArray[3]="qwerty";
testArray[7]="asdfgh";
testArray[13]="zxcvbn";
var testString = testArray.filter(function (item) { return item != undefined }).join();
$(function(){
$('#write').text(testString);
});
filter prototype:
过滤器原型：
if (!Array.prototype.filter)
{
Array.prototype.filter = function(fun /*, thisp */)
{
"use strict";
if (this === void 0 || this === null)
throw new TypeError();
var t = Object(this);
var len = t.length >>> 0;
if (typeof fun !== "function")
throw new TypeError();
var res = [];
var thisp = arguments[1];
for (var i = 0; i < len; i++)
{
if (i in t)
{
var val = t[i]; // in case fun mutates this
if (fun.call(thisp, val, i, t))
res.push(val);
}
}
return res;
};
}
回答by Redsandro
Array.prototype.filter()is not executed on deleted or previously undefined items. So you can simply do:
Array.prototype.filter()不会对已删除或以前未定义的项目执行。所以你可以简单地做：
testArray.filter(function(val){return val});
..in order to re-index your array.
..为了重新索引你的数组。
Or ES6:
或 ES6：
testArray.filter(val => val)
回答by Arron
Super simple function:
超级简单的功能：
function reindex_array_keys(array, start){
var temp = [];
start = typeof start == 'undefined' ? 0 : start;
start = typeof start != 'number' ? 0 : start;
for(var i in array){
temp[start++] = array[i];
}
return temp;
}
testArray = reindex_array_keys(testArray);
Note: this will blow away any custom keys. the result will always be numerically indexed. you could add in checks for if it's an array or not but i tend to just not use functions i build other than they are intended to be used. you can also start the index higher if you like:
注意：这将吹走任何自定义键。结果将始终以数字索引。您可以添加检查它是否是数组，但我倾向于不使用我构建的函数，而不是打算使用的函数。如果您愿意，也可以将索引设置得更高：
testArray = reindex_array_keys(testArray, 3);
which will produce 3 'undefined' items at the beginning of the array. you can then add to it later but i think it would be better to do testArray.unshift('newValue')first then reindex personally.
这将在数组的开头产生 3 个“未定义”项。你可以稍后再添加它，但我认为最好先做testArray.unshift('newValue')然后亲自重新索引。
have fun
玩得开心
回答by Nina Scholz
You could filter the array by using a callback which returns trueor other truthyvalue, because Array#filteromits sparse elements.
您可以使用返回true或其他真实值的回调来过滤数组，因为Array#filter省略了稀疏元素。
If Booleanis taken, the result filters not only sparse items, but items which have a falsyvalue. To prevent this, take a callback which returns truefor every element.
如果Boolean采用，结果不仅会过滤稀疏项，还会过滤具有虚假值的项。为了防止这种情况，采取一个true为每个元素返回的回调。
array.filter(_ => true);
var array = [];
array[10] = 0;
array[20] = 0;
array[30] = 0;
console.log(array.filter(_ => true).join('|'))回答by capdragon
var testArray = new Array();
testArray[3] = "qwerty";
testArray[7] = "asdfgh";
testArray[13] = "zxcvbn";
var isEmpty = function(x) {
// returns true if x is null and false if it is not.
if(x!=null){
return true;
}else{
return false
}
}
var newArray=testArray.filter(isEmpty);
var testString2 = newArray.join();
$('#write').text(testString2);
回答by elasticrash
you mean without the commas? if so just do this var testString = testArray.join("");or you can add any char you want between.
你的意思是没有逗号？如果是这样，就这样做，var testString = testArray.join("");或者您可以在两者之间添加任何您想要的字符。
回答by Wazy
TryThis
试试这个
var testArray=testArray.join(" ");
