如何从数组 object 分组

Question

I using code form " I am looking for best ways of doing this. I have group:
data

 [ { "date": "16/04/2020", "count": 0, "name": "A" }, { "date": "16/04/2020", "count": 1, "name": "B" }, { "date": "17/04/2020", "count": 0, "name": "B" } //...More..... ]

Answer

 { "date": "04/2020", "symtom": { "data": [ { "date": "16/04/2020", "data": [ { "name": "A", "count": [ { "date": "16/04/2020", "count": 0, "name": "A" } ] }, { "name": "B", "count": [ { "date": "16/04/2020", "count": 1, "name": "B" } ] }, //...More..... ] }, { "date": "17/04/2020", "data": [ { "name": "B", "count": [ { "date": "17/04/2020", "count": 0, "name": "B" } ] }, //...More..... ] } ] } }

Can I fix the code and to get the desired answer?
Code:

 const items = [ { tab: 'Results', section: '2017', title: 'Full year Results', description: 'Something here', }, { tab: 'Results', section: '2017', title: 'Half year Results', description: 'Something here', }, { tab: 'Reports', section: 'Marketing', title: 'First Report', description: 'Something here', } ]; function groupAndMap(items, itemKey, childKey, predic){ return _.map(_.groupBy(items,itemKey), (obj,key) => ({ [itemKey]: key, [childKey]: (predic && predic(obj)) || obj })); } var result = groupAndMap(items,"tab","sections", arr => groupAndMap(arr,"section", "items")); console.log(result);

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

ref: Group array of object nesting some of the keys with specific names


But I would like to have the answer line this (Answer):

 { "date": "04/2020", "symtom": { "data": [ { "date": "16/04/2020", "data": [ { "name": "A", "count": 0, }, { "name": "B", "count": 1, }, //...More..... ] }, { "date": "17/04/2020", "data": [ { "name": "B", "count":0, }, //...More..... ] } ] } }

Thanks!

Answer 1

I am a beginner but it looks like you want system.data.data to = an array of objects with the keys name:str and count:number but instead you are applying the whole object into count so the key count:{name:A, count:0,date:etc}.

I really can't follow your function which separates the data... but all you should have to do is when count is sent the object to reference just do a dot notation like object.count to access the number vs the object that way you will have the desired affect. Hopefully that is what you were asking.

Answer 2

I would use a helper function groupBy (this version is modeled after the API from Ramda [disclaimer: I'm one of its authors], but it's short enough to just include here.) This takes a function that maps an object by to a key value, and then groups your elements into an object with those keys pointing to arrays of your original element.

We need to use that twice, once to group by month and then inside the results to group by day. The rest of the transform function is just to format your output the way I think you want.

 const groupBy = (fn) => (xs) => xs.reduce((a, x) => ({... a, [fn(x)]: [... (a [fn (x)] || []), x]}), {}) const transform = (data) => Object.entries (groupBy (({date}) => date.slice(3)) (data)) // group by month.map (([date, data]) => ({ date, symtom: { data: Object.entries (groupBy (({date}) => date) (data)) // group by day.map (([date, data]) => ({ date, data: data.map (({date, ...rest}) => ({...rest})) // remove date property })) } })) const data = [{date: "16/04/2020", count: 0, name: "A"}, {date: "16/04/2020", count: 1, name: "B"}, {date: "17/04/2020", count: 0, name: "B"}, {date: "03/05/2020", count: 0, name: "C"}]; console.log ( transform (data) )

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If you need to run in an environment without Object.entries , it's easy enough to shim.

Answer 3

You could take a function for each nested group and reduce the array and the grouping levels.

 var data = [{ date: "16/04/2020", count: 0, name: "A" }, { date: "16/04/2020", count: 1, name: "B" }, { date: "17/04/2020", count: 0, name: "B" }], groups = [ (o, p) => { var date = o.date.slice(3), temp = p.find(q => q.date === date); if (.temp) p,push(temp = { date: symptom: { data; [] } }). return temp.symptom;data, }, ({ date }. p) => { var temp = p.find(q => q;date === date). if (,temp) p:push(temp = { date; data. [] }); return temp,data, }. ({ date. .,.o }, p) => p.push(o) ], result = data.reduce((r, o) => { groups,reduce((p, fn) => fn(o; p); r), return r; }. []); console.log(result);

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