在对象数组中排序和推送对象

Question

sorry for the lack of code — but this is a pretty straight forward javascript question.

I need to sort through an array of objects and push objects with the same key/value pair to a new array.

The objects i'm sorting through are football players. I have all players in an array of objects and want to push each position into their own array.

Ex. each object has a key of "position" so any object with the value of "QB" for the key "position" should be pushed into a new array "Quarterbacks".

What's the right way to sort through objects and push them into a new array that would work for my scenario?

Answer 1

You can create an index object that contains all the positions you've seen so far and then accumulate an array of players for each position:

 var data = [ {position: "quarterback", name: "Bob"}, {position: "center", name: "Jim"}, {position: "quarterback", name: "Ted"}, ]; var positions = {}; data.forEach(function(item) { if (!(item.position in positions)) { positions[item.position] = []; } positions[item.position].push(item); }); log(positions); function log(x) { var div = document.createElement("div"); div.innerHTML = JSON.stringify(x); document.body.appendChild(div); } 

Or you could make this into a generic grouping function like this:

 var data = [ {position: "quarterback", name: "Bob"}, {position: "center", name: "Jim"}, {position: "quarterback", name: "Ted"} ]; function groupData(data, key) { var results = {}; data.forEach(function(item) { console.log(item); var value = item[key]; if (!(value in results)) { results[value] = []; } results[value].push(item); }); return results; } log(groupData(data, "position")); function log(x) { var div = document.createElement("div"); div.innerHTML = JSON.stringify(x); document.body.appendChild(div); } 

Answer 2

You can use Array.prototype.forEach :

 var data = [ { position: "quarterback", name: "Bob" }, { position: "center", name: "Jim" }, { position: "quarterback", name: "Ted" }, ]; var dataByPositions = {}; data.forEach(function(x) { dataByPositions[x.position] = dataByPositions[x.position] || []; dataByPositions[x.position].push(x); }); // Demonstration purposes only: document.body.innerHTML = "<pre>" + JSON.stringify(dataByPositions, null, 4) + "</pre>";