Question

我有两个json类型的数据“A”和“B”它们都有相同类型的类别

> db.orders.createIndex({item: 1})
{
    "createdCollectionAutomatically" : true,
    "numIndexesBefore" : 1,
    "numIndexesAfter" : 2,
    "ok" : 1
}
> db.orders.insert({item: undefined})
WriteResult({ "nInserted" : 1 })
> db.orders.find({item: {$type: 6}}).explain()
{
    "queryPlanner" : {
        "plannerVersion" : 1,
        "namespace" : "temp.orders",
        "indexFilterSet" : false,
        "parsedQuery" : {
            "item" : {
                "$type" : 6
            }
        },
        "winningPlan" : {
            "stage" : "FETCH",
            "filter" : {
                "item" : {
                    "$type" : 6
                }
            },
            "inputStage" : {
                "stage" : "IXSCAN",
                "keyPattern" : {
                    "item" : 1
                },
                "indexName" : "item_1",
                "isMultiKey" : false,
                "isUnique" : false,
                "isSparse" : false,
                "isPartial" : false,
                "indexVersion" : 1,
                "direction" : "forward",
                "indexBounds" : {
                    "item" : [
                        "[undefined, undefined]"
                    ]
                }
            }
        },
        "rejectedPlans" : [ ]
    },
    "serverInfo" : {
        "host" : "Andys-MacBook-Pro-2.local",
        "port" : 27017,
        "version" : "3.2.8",
        "gitVersion" : "ed70e33130c977bda0024c125b56d159573dbaf0"
    },
    "ok" : 1
}

是否有使用lodash功能？如果在“A”中有相同型号的车辆，则与“B”相比，模型将不会显示

Answer 1

使用原生Javascript，您可以使用array#filter和array#some。

这里将获取模型数组中没有模型的汽车。

＆＃13;

const cars = {"A":[{"id": "1","vehicle": {"model": "toyota"}},{"id":"2","vehicle": {"model": "vios"}},{"id":"3","vehicle": {"model": "honda"}},{"id":"4","vehicle": {"model": "eon"}},{"id":"5","vehicle": {"model": "motor"}}]};

const models = {"B":[{"model": "volkswagen"},{"model": "hyundai"},{"model": "honda"},{"model": "mitsubishi"},{"model": "bmw"}]};

var result = cars.A.filter((car) => {
  return !models.B.some((model) => model.model === car.vehicle.model ) 
});

console.log(result);

＆＃13;

.as-console-wrapper { max-height: 100% !important; top: 0; }

＆＃13;

如果您想要没有汽车的车型。

＆＃13;

const cars = {"A":[{"id": "1","vehicle": {"model": "toyota"}},{"id":"2","vehicle": {"model": "vios"}},{"id":"3","vehicle": {"model": "honda"}},{"id":"4","vehicle": {"model": "eon"}},{"id":"5","vehicle": {"model": "motor"}}]};

const models = {"B":[{"model": "volkswagen"},{"model": "hyundai"},{"model": "honda"},{"model": "mitsubishi"},{"model": "bmw"}]};

var result = models.B.filter((model) => {
  return !cars.A.some((car) => model.model === car.vehicle.model ) 
});

console.log(result);

＆＃13;

.as-console-wrapper { max-height: 100% !important; top: 0; }

＆＃13;

这是一个lodash解决方案：

＆＃13;

const cars = {"A":[{"id": "1","vehicle": {"model": "toyota"}},{"id":"2","vehicle": {"model": "vios"}},{"id":"3","vehicle": {"model": "honda"}},{"id":"4","vehicle": {"model": "eon"}},{"id":"5","vehicle": {"model": "motor"}}]};

const models = {"B":[{"model": "volkswagen"},{"model": "hyundai"},{"model": "honda"},{"model": "mitsubishi"},{"model": "bmw"}]};

var result = _.filter(models.B, (model) =>
    !_.some(cars.A, (car) => model.model === car.vehicle.model));

console.log(result);

＆＃13;

.as-console-wrapper { max-height: 100% !important; top: 0; }

＆＃13;

<script src='https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.4/lodash.js'></script>

＆＃13;

Answer 2

你可以使用_.isEqual，但你必须确保外部数组已经排序

var array1 = [['a', 'b'], ['b', 'c']];
var array2 = [['b', 'c'], ['a', 'b']];
_.isEqual(array1.sort(), array2.sort()); //true

也可以使用ES6：

array2.filter(e => !array1.includes(e));

Answer 3

不是在lodash中，而是在普通的javascript中。以下代码采用var A作为您在A中提供的内容，同样适用于B

const filterList = B.map(b => b.model);
const notInB = A.filter(a => filterList.indexOf(a.vehicle.model) < 0);

notInB中的值应包含A中不在B中的值，顾名思义。

修改

我提供了一个jsfiddle来说明这一点：https://jsfiddle.net/cattails27/zvc53j5g/

Answer 4

为什么不只是做一个普通的for循环，如果模型存在就使用_.find？

在lodash中是否存在比较两个对象数组的情况，如果结果相同则不会显示

4 个答案: