关联阵列拼接不起作用 [英] Associate Array splice does not work

问题描述

我试图理解为什么在nodejs数组中拼接不能在关联数组上工作.

I am trying to understand why in nodejs array splice does not work on an associate array.

var a = [];

a['x1'] = 234234;
a['x2'] = 565464;

console.log("Init-------");
showIt();

a.splice(0, 1);
console.log("After splice-------");
showIt();

delete a['x1'];
console.log("After delete-------");
showIt();

function showIt(){
    var keys = Object.keys(a);
    var len  = keys.length;
    var i=0;
    while (i < len) {
        console.log( '    ' + i +  ' ------------ ' + keys[i] );
        i++;
    }
}

结果:

Init-------
        0 ------------ x1
        1 ------------ x2
After splice-------
        0 ------------ x1
        1 ------------ x2
After delete-------
        0 ------------ x2

拼接数组无济于事...

Splicing the array does nothing...

浏览器中的结果相同...

Same results in a browser...

将数组定义为以下参数时，拼接工作正常:

Splice works as expected when the array is defined as:

var a = ['x1','x2','x3'];
console.log("Init-------");
console.log(a);

a.splice('x1', 1);
console.log("After splice-------");
console.log(a);

就像在第一个示例中一样，该数组被视为好像在第二个中被定义为对象{}一样，它被视为一个数组.

Looks like in the first example, the array is being treated as if is was defined as a object {} in the 2nd, it's being treated more like an array.

这实际上不是关于备用阵列的问题，它更多地是关于一个阵列的问题，该阵列从0开始并在几天内连续增长到1000万.随着阵列的增长，阵列中的数据将被删除，以便一次在阵列中存储大约1000个项目.

This is not really a question about spare arrays, it is more of a question of an array which is starting at 0 and growing sequentially to 10 million over a period of days. As it is growing the array is being deleted from so that around 1000 items are in the array at one time.

我正在考虑通过使用非数字键或将其定义为对象{}来强制使用哈希表，以便其作用类似于稀疏数组.

I am considering forcing the use of hash tables by using non-numeric keys or defining as a object {} so that the it acts like a sparse array.

最后，我不确定这是否重要...

In the end, I am not sure if it matters...

推荐答案

在JavaScript中，没有关联数组之类的东西-数组(如其他语言的普通数组)和对象(如其他语言的assoc数组)语言).在您的示例中，a是普通数组，但是您在其上设置了非数字键，因此普通数组方法(例如splice)看不到它.它们仅在0...a.length范围内.

In JavaScript there is no such thing as an associative array -- there are arrays (like normal arrays in other languages) and objects (like assoc. arrays in other languages). In your example a is a normal array but you set non-numerical keys on it, so the normal array methods (like splice) do not see it. They only look in the range 0...a.length.

制作a对象无济于事；无法拼接对象.尝试仅使用数字键([1]而不是['x1']).

Making a an object won't help; it is not possible to splice an object. Try using only numerical keys ([1] instead of ['x1']).

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