如何在对象内部找到数组

Question

I have parkingSpots that is an array of objects which contains a property of coordinates which is also an array.

eg index 0:

_id: "5e03c83459d0c115589067ba"
capacity: 2
description: "safas"
title: "aa"
coordinates: (2) [-34.193705512748686, 150.2320126953125]

I'm trying to find the object that has the arrayToBeFound . I tries this solution and many others but still doesn't work.

    let arrayToBeFound = [e.latLng.lat(), e.latLng.lng()];
    let selectedParkingSpot = parkingSpots.find(x => x.coordinates === arrayToBeFound);

I keep getting undefined but it exists. Any help?

Answer 1

You need to compare two arrays by comparing each item of the first array with the corresponding item of another array. Directly comparing an array against another array will never work - they always be different, because JS compares arrays (objects) by their reference. Only if both references point to the same array they will be equal. The primitives however are compared by value.

 let selectedParkingSpot = parkingSpots.find(x => x.coordinates[0] === arrayToBeFound[0] && x.coordinates[1] === arrayToBeFound[1]);

Answer 2

我认为这是最简单的方法

let selectedParkingSpot = parkingSpots.find(x => x.coordinates[0] === arrayToBeFound[0] && x.coordinates[1] === arrayToBeFound[1]);

Answer 3

You can use the answers being posted here, I like them more except if you are going to add values to that array, or perform comparisons between other arrays and/or object, or if you don't care about your array's order.

Otherwise, you can use Lodash's isEqual to compare objects by their values.

Answer 4

 $(document).ready(function() { function arraysEqual(a, b) { if (a === b) return true; if (a == null || b == null) return false; if (a.length != b.length) return false; for (var i = 0; i < a.length; ++i) { if (a[i] !== b[i]) return false; } return true; } var arrayOfObjects = [{ _id: "5e03c83459d0c115589067ba", capacity: 2, description: "safas", title: "aa", coordinates: [-34.193705512748686, 160.2320126953125], }, { _id: "5e03c83459d0c115589067ba", capacity: 2, description: "safas", title: "aa", coordinates: [-34.193705512748686, 150.2320126953125], }]; var arrayToBeFound = [-34.193705512748686, 150.2320126953125]; $.each(arrayOfObjects, function(index, object){ if(arraysEqual(arrayToBeFound, object.coordinates)){ console.log(arrayOfObjects[index]); } }); });

 <script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>

Answer 5

You can't compare 2 arrays but if you stringify them it will work.

const data = [
    {
        _id: "5e03c83459d0c115589067ba",
        capacity: 2,
        description: "safas",
        title: "aa",
        coordinates: [-34.193705512748686, 150.2320126953125]
    }
]
const arrayToBeFound = [-34.193705512748686, 150.2320126953125]

let spot = data.find((ele)=>{
    return JSON.stringify(ele.coordinates) === JSON.stringify(arrayToBeFound)
})

// returns the object
console.log(spot)

// returns false
console.log(data[0].coordinates == arrayToBeFound)

//returns true
console.log(typeof data[0].coordinates === typeof arrayToBeFound)

The reason why you got undefined is because the comparison of x.coordinates == arrayToBeFound returns false there fore find won't return any thing and since selectedParkingSpot holds no value it will be undefined.