[英]How to extract multiple array of objects from Json data containing multiple array of objects?
[英]Extract 3 arrays of data from Array of JSON objects
我有一個定義如下的JSON對象數組:
[
{
key : "test1",
data : {
"Mercedes" : {
"ClassA" : [1, 2],
"ClassB" : [1]
},
"Benz" : {
"ClassA" : [1]]
}
}
},
{
key : "test2",
data : {
"Mercedes" : {
"ClassA" : [1, 2, 3],
"ClassB" : [1]
},
"Toty" : {
"ClassA" : [1]]
}
}
},...
]
我想檢索3個distinct數組:
result = ["Mercedes", "Benz", "Toty"]
type = ["ClassA", "ClassB"]
numbers = ["1", "2", "3"]
我如何檢索這3個數組而無需糾正多個循環?
這不是完美的,可以使用更清潔的“ JS-y”方式完成,但是在這里
var someArray = ...; // your input array
var uniqueCars = new Set();
var uniqueClasses = new Set();
for (var i = 0; i < someArray.length; i++) {
// iterate through all prop names
for (var carProp in someArray[i].data) {
uniqueCars.add(carProp);
for (var classProp in someArray[i].data[carProp]) {
uniqueClasses.add(classProp);
// Too lazy to do the last one, hopefully you can figure it out
}
}
}
var finalCars = Array.from(uniqueCars);
var finalClasses = Array.from(uniqueClasses);
// do the 3rd one you asked for
退房reduce
-的多種可能的方式,你可以做到這一點的。
var data = [{ key: "test1", data: { "Mercedes": { "ClassA": [1, 2], "ClassB": [1] }, "Benz": { "ClassA": [1] } } }, { key: "test2", data: { "Mercedes": { "ClassA": [1, 2, 3], "ClassB": [1] }, "Toty": { "ClassA": [1] } } } ]; var thing = data.reduce((acc, itm) => { for (var type in itm.data) { if (acc.types.indexOf(type) === -1) acc.types.push(type); for (var cls in itm.data[type]) { if (acc.classes.indexOf(cls) === -1) acc.classes.push(cls); for (var i = itm.data[type][cls].length; i--;) if (acc.numbers.indexOf(itm.data[type][cls][i]) === -1) acc.numbers.push(itm.data[type][cls][i]); } } return acc; }, { types: [], numbers: [], classes: [] }); console.log('Unique Types', thing.types); console.log('Unique Numbers', thing.numbers); console.log('Unique Classes', thing.classes);
這只是概念的證明,但我認為可以將其做成遞歸函數並變得更優雅。
let arr = [{ key: "test1", data: { "Mercedes": { "ClassA": [1, 2], "ClassB": [1] }, "Benz": { "ClassA": [1] } } }, { key: "test2", data: { "Mercedes": { "ClassA": [1, 2, 3], "ClassB": [1] }, "Toty": { "ClassA": [1] } } }], flatten = (a, b) => [...a, ...b], allUnq = a => [...new Set(a.reduce(flatten))], data = arr.map(o => o.data), vals = d => d.map(Object.values), keys = d => d.map(Object.keys), arr1 = allUnq(keys(data)), arr2 = allUnq(vals(data).map(keys).map(allUnq)), arr3 = allUnq(allUnq(vals(allUnq(vals(data))))); console.log(arr1); console.log(arr2); console.log(arr3);
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