如何通过比较对象的两个数组和对象中的不同元素来过滤数组? [英] How to filter array by comparing two arrays of objects with different elements in their objects?

问题描述

如何通过比较对象中两个具有不同元素的对象数组来过滤数组? 我有:

How to filter array by comparing two arrays of objects with different elements in their objects? I have:

arr1 =[{ x: 1, y: 2, z:3 }, { x: 2, y: 1, z:4 }];

arr2 = [{ x: 1, y: 2, a:5 }, { x: 2, y: 3, a:4 }];

我想比较两个数组中的x和y值，并从第一个数组中返回非宏对象，在上面的示例中，返回[{ x: 2, y: 1, z:4 }] 我尝试使用_.differenceWith(arr1, arr2, _.isEqual);，但是显然，数组应该具有类似的对象，而我不是这种情况.

I want to compare x and y values from both arrays and return the not macthing object from first array, in the above example return [{ x: 2, y: 1, z:4 }] I tried to use _.differenceWith(arr1, arr2, _.isEqual); but obviously for this the arrays should have similar objects which is not my case.

推荐答案

您非常接近正确的答案. lodash的_.differenceWith函数具有三个参数，要检查的数组，要排除的值，第三个参数是确定所需值的比较器.在您的情况下，使用_.isEqual查找完全相同的对象(据我了解，这不是您想要的行为).

You are very close to the right answer. The _.differenceWith function from lodash has three arguments, the array to inspect, the values to exclude and the third argument is a comparator which determines which values you need. In your case, using _.isEqual is looking for exactly the same object (which as far as I understood is not your desired behavior).

如果只关心具有相同的x和y值，请尝试使用自定义比较器，而不是lodash的_.isEqual函数.

If you only care about having same x and y values, try using your custom comparator instead of the _.isEqual function from lodash.

它看起来像这样:

const arr1 = [{ x: 1, y: 2, z:3 }, { x: 2, y: 1, z:4 }];    
const arr2 = [{ x: 1, y: 2, a:5 }, { x: 2, y: 3, a:4 }];

// this is your custom comparator which is called with each value from the two arrays
// I gave descriptive names to the arguments so that it is more clear
const customComparator = (valueFromFirstArray, valueFromSecondArray) =>
  valueFromFirstArray.x === valueFromSecondArray.x
  && valueFromFirstArray.y === valueFromSecondArray.y;

const result = _.differenceWith(arr1, arr2, customComparator);

console.log(result);
// will print [{x: 2, y: 1, z: 4}]

或者，如果您不熟悉箭头功能，则可以这样声明自定义比较器:

Or if you are not familiar with arrow functions, the custom comparator can be declared like this:

function customComparator(valueFromFirstArray, valueFromSecondArray) {
  return valueFromFirstArray.x === valueFromSecondArray.x
    && valueFromFirstArray.y === valueFromSecondArray.y
}

这是一个小提琴，您可以在其中与自定义比较器混合

Here is a fiddle where you can mingle around with the custom comparator if you'd like to.

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