javascript查找数组项的父级 [英] javascript find parent of array item
问题描述
我有一个像这样的数组项:
I have an array item like this:
var array = USA.NY[2];
// gives "Albany"
{"USA" : {
"NY" : ["New York City", "Long Island", "Albany"]
}}
我只想从数组中查找状态.我该怎么做呢?谢谢.
I want to find the state from just having the array. How do I do this? Thanks.
function findParent(array) {
// do something
// return NY
}
推荐答案
在Javascript中,数组元素没有引用包含它们的数组.
In Javascript, array elements have no reference to the array(s) containing them.
要实现此目的,您将需要引用"root"数组,这取决于您的数据模型.
假设USA是可访问的,并且仅包含数组,则可以执行以下操作:
To achieve this, you will have to have a reference to the 'root' array, which will depend on your data model.
Assuming USA is accessible, and contains only arrays, you could do this:
function findParent(item) {
var member, i, array;
for (member in USA) {
if (USA.hasOwnProperty(member) && typeof USA[member] === 'object' && USA[member] instanceof Array) {
array = USA[member];
for(i = 0; i < array.length; i += 1) {
if (array[i] === item) {
return array;
}
}
}
}
}
请注意,由于您传递的是值(和数组项),因此我已将 array
参数重命名为 item
,并且希望返回数组.
如果您想知道数组的名称,则应该返回 member
.
Note that I’ve renamed the array
parameter to item
since you’re passing along a value (and array item), and you expect the array to be returned.
If you want to know the name of the array, you should return member
instead.
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