Javascript 使用 Jquery $.grep 过滤对象数组而不使用对象包装器
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Filtering an Array of Objects using Jquery $.grep without an Object Wrapper
提问by Question Overflow
Filtering works fine for an object (data) wrapping around an array of objects:
过滤适用于data环绕对象数组的对象( )：
var arr = {"data":
[
{"name":"Alan","height":"171","weight":"66"},
{"name":"Ben","height":"182","weight":"90"},
{"name":"Chris","height":"163","weight":"71"}
]
};
var new_arr = $.extend(true, arr);
new_arr.data = $.grep(new_arr.data, function(n, i){
return n.weight > 70;
});
alert(new_arr.data.length); // answer is 2
However, filtering without the object wrapper doesn't.
但是，没有对象包装器的过滤不会。
var arr = [
{"name":"Alan","height":"171","weight":"66"},
{"name":"Ben","height":"182","weight":"90"},
{"name":"Chris","height":"163","weight":"71"}
];
var new_arr = $.extend(true, arr);
new_arr = $.grep(new_arr, function(n, i){
return n.weight > 70;
});
alert(new_arr.length); // answer is 1 instead of 2
I am not sure where is the problem. Can anyone point out. Thanks!
我不确定问题出在哪里。谁能指点一下。谢谢！
回答by Dane O'Connor
You're using extendincorrectly. You can't extend the new_arr with an array. Extend will add methods/props to an object but what methods/props will it create when it runs into your array? This is why it works with the object wrapper: 1) extend expects an object and 2) 'data' is a property that can be added to new_arry.
您使用的扩展不正确。你不能用数组扩展 new_arr 。Extend 将向对象添加方法/道具，但是当它运行到您的数组时会创建什么方法/道具？这就是它与对象包装器一起工作的原因：1）extend 需要一个对象，2）'data' 是一个可以添加到 new_arry 的属性。
Despite, in your second example, it doesn't look like you need to extend anything. Does this work?
尽管如此，在您的第二个示例中，您似乎不需要扩展任何内容。这行得通吗？
new_arr = $.grep(arr, function(n, i){ // just use arr
return n.weight > 70;
});
回答by David Lopes
You can use this to a object more deep,
您可以将其用于更深的对象，
var prodIds = [];
$.grep(this.prodOrders, function (n, i) {
$.grep(n.ProductionOrderLines, function (n2, i2) {
if (n2.ItemNo == resource) {
prodIds.push(n2.DocumentAbsoluteEntry);
}
});
});
