javascript 将值设置为关联数组
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javascript set value to Associative Arrays
提问by user319854
how set value in javascript to Associative Arrays?
如何将javascript中的值设置为关联数组？
Why in this case i get error: "car[0] is undefined"
为什么在这种情况下我收到错误：“汽车 [0] 未定义”
var car = new Array();
car[0]['name'] = 'My name';
回答by ThiefMaster
Because you never defined car[0]. You have to initialize it with an (empty) object:
因为你从来没有定义car[0]. 您必须使用（空）对象对其进行初始化：
var car = [];
car[0] = {};
car[0]['name'] = 'My name';
Another solution would be this:
另一种解决方案是这样的：
var car = [{name: 'My Name'}];
or this one:
或者这个：
var car = [];
car[0] = {name: 'My Name'};
or this one:
或者这个：
var car = [];
car.push({name: 'My Name'});
回答by Bj?rn
var car = [];
car.push({
'name': 'My name'
});
回答by Eric Bréchemier
You are taking two steps at once: the item 0 in the car array is undefined. You need an object to set the value of the 'name' property.
您同时采取两个步骤：汽车数组中的项目 0 未定义。您需要一个对象来设置“名称”属性的值。
You can initialize an empty object in car[0] like this:
您可以像这样在 car[0] 中初始化一个空对象：
car[0] = {};
There is no need to call the Array() constructor on the first line. This could be written:
不需要在第一行调用 Array() 构造函数。这可以写成：
var car = [];
and if you want to have an object in the array:
如果你想在数组中有一个对象：
var car = [{}];
回答by gion_13
in your example, car[0]is not initialized and it is undefined, and undefinedvariables cannot have properties (after all, setting an associative array's value means setting the object's method).
在您的示例中，car[0]未初始化并且是undefined，并且undefined变量不能具有属性（毕竟，设置关联数组的值意味着设置对象的方法）。
