使用 Jquery $.grep 过滤对象数组而不使用对象包装器

发布于 2024-12-21 12:30:44 字数 810 浏览 0 评论 0原文

过滤对于包装对象数组的对象 (data) 效果很好：

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

但是，没有对象包装器的过滤则不然。

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

我不确定问题出在哪里。谁能指点一下。谢谢！

原文

Filtering works fine for an object (data) wrapping around an array of objects:

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.

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!

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七月上 2024-12-28 12:30:44

您错误地使用了 extend 。您不能使用数组扩展 new_arr 。 Extend 会将方法/道具添加到对象中，但是当它遇到数组时它将创建哪些方法/道具？这就是它与对象包装器一起使用的原因：1）extend 需要一个对象，2）“data”是一个可以添加到 new_arry 的属性。

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。这有效吗？

new_arr = $.grep(arr, function(n, i){ // just use arr
  return n.weight > 70;
});

You're using extend incorrectly. 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.

Despite, in your second example, it doesn't look like you need to extend anything. Does this work?

new_arr = $.grep(arr, function(n, i){ // just use arr
  return n.weight > 70;
});

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生死何惧 2024-12-28 12:30:44

您可以将其用于更深入的对象，

var prodIds = [];

        $.grep(this.prodOrders, function (n, i) { 

            $.grep(n.ProductionOrderLines, function (n2, i2) { 
                if (n2.ItemNo == resource) {
                    prodIds.push(n2.DocumentAbsoluteEntry);
                }
            });
        });

You can use this to a object more deep,

var prodIds = [];

        $.grep(this.prodOrders, function (n, i) { 

            $.grep(n.ProductionOrderLines, function (n2, i2) { 
                if (n2.ItemNo == resource) {
                    prodIds.push(n2.DocumentAbsoluteEntry);
                }
            });
        });

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~没有更多了~