Creating a new array by comparing an array of objects to an array

Question

I have a list of gameData and used athletes. I need to make a new array that only contains Athlete from gameData that is not in usedAthletes. I've honestly looked all over, tried lodash and various things over the past day or so. Any advise would be great. If there are ES6 methods that work it would be cool to know that too :)

const gameData = [
        {Athlete: "Peyton Manning", Img: "url"},
        {Athlete: "Tony Hawk", Img: "url"},
        {Athlete: "Tom Brady", Img: "url"},
        {Athlete: "Usain Bolt", Img: "url"},
        {Athlete: "Kevin Durant", Img: "url"},
        {Athlete: "Cristiano Ronaldo", Img: "url"},
        {Athlete: "Michael Phelps", Img: "url"},
        {Athlete: "Conor McGregor", Img: "url"},
        {Athlete: "Phil Mickelson", Img: "url"},
        {Athlete: "Stephen Curry", Img: "url"},
        {Athlete: "Rory McIlroy", Img: "url"},
        {Athlete: "Mike Trout", Img: "url"},
        {Athlete: "Danica Patrick", Img: "url"},
        {Athlete: "Drew Brees", Img: "url"},
        {Athlete: "Carmelo Anthony", Img: "url"},
        {Athlete: "Ryan Lochte", Img: "url"},
        {Athlete: "Eli Manning", Img: "url"},
        {Athlete: "Chris Paul", Img: "url"}
]

const usedAthletes = ["Peyton Manning", "Tony Hawk", "Tom Brady"];

gameData.forEach( x => {
  const gameDataNamesOnly = x.Athlete;
  newAnswerlist = [];
  usedAthletes.forEach( item => {
    if(gameDataNamesOnly != item){
        //I was trying to push to newAnswerList here but could get access to gameDataNamesOnly correctly or something.
    }
  })
  console.log(newAnswerlist)
})

pratZ · Accepted Answer · 2017-08-01 17:48:37Z

1

Use filter followed by map,

const newAnswerlist = gameData
.filter(data => usedAthletes.indexOf(data.Athlete) !== -1)
.map(data => data.Athlete);

Use only filter if you want the img information too,

const newAnswerlist = gameData
.filter(data => usedAthletes.indexOf(data.Athlete) !== -1);

edited Aug 1, 2017 at 17:48

answered Aug 1, 2017 at 17:33

pratZ

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3 Comments

SirFry Over a year ago

I tried this but when I console log newAnswerlist it returns an empty array.

pratZ Over a year ago

@SirFry There was a typo in Athelete, made it Athlete

SirFry Over a year ago

lul I missed that too, sorry at work right now. Thanks for the help!

Nina Scholz · Accepted Answer · 2017-08-01 17:31:04Z

You could use Array#filter with Array#includes and exclude the usedAthletes.

You solution does not work, because you initialize the result array in every iteration.

const
    gameData = [{ Athlete: "Peyton Manning", Img: "url" }, { Athlete: "Tony Hawk", Img: "url" }, { Athlete: "Tom Brady", Img: "url" }, { Athlete: "Usain Bolt", Img: "url" }, { Athlete: "Kevin Durant", Img: "url" }, { Athlete: "Cristiano Ronaldo", Img: "url" }, { Athlete: "Michael Phelps", Img: "url" }, { Athlete: "Conor McGregor", Img: "url" }, { Athlete: "Phil Mickelson", Img: "url" }, { Athlete: "Stephen Curry", Img: "url" }, { Athlete: "Rory McIlroy", Img: "url" }, { Athlete: "Mike Trout", Img: "url" }, { Athlete: "Danica Patrick", Img: "url" }, { Athlete: "Drew Brees", Img: "url" }, { Athlete: "Carmelo Anthony", Img: "url" }, { Athlete: "Ryan Lochte", Img: "url" }, { Athlete: "Eli Manning", Img: "url" }, { Athlete: "Chris Paul", Img: "url" }],
    usedAthletes = ["Peyton Manning", "Tony Hawk", "Tom Brady"],
    result = gameData.filter(o => !usedAthletes.includes(o.Athlete));
      
console.log(result);

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

Rahul Singh · Accepted Answer · 2017-08-01 17:38:15Z

const gameData = [
        {Athlete: "Peyton Manning", Img: "url"},
        {Athlete: "Tony Hawk", Img: "url"},
        {Athlete: "Tom Brady", Img: "url"},
        {Athlete: "Usain Bolt", Img: "url"},
        {Athlete: "Kevin Durant", Img: "url"},
        {Athlete: "Cristiano Ronaldo", Img: "url"},
        {Athlete: "Michael Phelps", Img: "url"},
        {Athlete: "Conor McGregor", Img: "url"},
        {Athlete: "Phil Mickelson", Img: "url"},
        {Athlete: "Stephen Curry", Img: "url"},
        {Athlete: "Rory McIlroy", Img: "url"},
        {Athlete: "Mike Trout", Img: "url"},
        {Athlete: "Danica Patrick", Img: "url"},
        {Athlete: "Drew Brees", Img: "url"},
        {Athlete: "Carmelo Anthony", Img: "url"},
        {Athlete: "Ryan Lochte", Img: "url"},
        {Athlete: "Eli Manning", Img: "url"},
        {Athlete: "Chris Paul", Img: "url"}
];

const usedAthletes = ["Peyton Manning", "Tony Hawk", "Tom Brady"];


var value = gameData.map((data) => {if(!usedAthletes.includes(data.Athlete)){return data;}}).filter((data) => data);

console.log(value);

Anthony Ngene · Accepted Answer · 2017-08-01 17:46:32Z

1

Try this:

const gameData = [
        {Athlete: "Peyton Manning", Img: "url"},
        {Athlete: "Tony Hawk", Img: "url"},
        {Athlete: "Tom Brady", Img: "url"},
        {Athlete: "Usain Bolt", Img: "url"},
        {Athlete: "Kevin Durant", Img: "url"},
        {Athlete: "Cristiano Ronaldo", Img: "url"},
        {Athlete: "Michael Phelps", Img: "url"},
        {Athlete: "Conor McGregor", Img: "url"},
        {Athlete: "Phil Mickelson", Img: "url"},
        {Athlete: "Stephen Curry", Img: "url"},
        {Athlete: "Rory McIlroy", Img: "url"},
        {Athlete: "Mike Trout", Img: "url"},
        {Athlete: "Danica Patrick", Img: "url"},
        {Athlete: "Drew Brees", Img: "url"},
        {Athlete: "Carmelo Anthony", Img: "url"},
        {Athlete: "Ryan Lochte", Img: "url"},
        {Athlete: "Eli Manning", Img: "url"},
        {Athlete: "Chris Paul", Img: "url"}
]

const usedAthletes = ["Peyton Manning", "Tony Hawk", "Tom Brady"];
const newAnswerlist = [];

gameData.forEach( data => {
  if (usedAthletes.indexOf(data.Athlete) == -1) {
    newAnswerlist.push(data.Athlete);
  }
});

newAnswerlist should contain the array you want.

edited Aug 1, 2017 at 17:46

answered Aug 1, 2017 at 17:39

Anthony Ngene

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2 Comments

SirFry Over a year ago

This works perfectly, I've been beating my head over this and had something a few tries ago looking similar to this but I must have messed something up. Thank you very much! :)

Anthony Ngene Over a year ago

Awesome, glad I could help.

Ori Drori · Accepted Answer · 2017-08-01 18:02:02Z

1

Lodash's _.differenceWith() creates an array of array values not included in the other given arrays using a comparator:

const gameData = [{"Athlete":"Peyton Manning","Img":"url"},{"Athlete":"Tony Hawk","Img":"url"},{"Athlete":"Tom Brady","Img":"url"},{"Athlete":"Usain Bolt","Img":"url"},{"Athlete":"Kevin Durant","Img":"url"},{"Athlete":"Cristiano Ronaldo","Img":"url"},{"Athlete":"Michael Phelps","Img":"url"},{"Athlete":"Conor McGregor","Img":"url"},{"Athlete":"Phil Mickelson","Img":"url"},{"Athlete":"Stephen Curry","Img":"url"},{"Athlete":"Rory McIlroy","Img":"url"},{"Athlete":"Mike Trout","Img":"url"},{"Athlete":"Danica Patrick","Img":"url"},{"Athlete":"Drew Brees","Img":"url"},{"Athlete":"Carmelo Anthony","Img":"url"},{"Athlete":"Ryan Lochte","Img":"url"},{"Athlete":"Eli Manning","Img":"url"},{"Athlete":"Chris Paul","Img":"url"}];

const usedAthletes = ["Peyton Manning", "Tony Hawk", "Tom Brady"];

const result = _.differenceWith(gameData, usedAthletes, ({ Athlete }, othVal) => Athlete === othVal);

console.log(result);

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

If you just need the athletes names, there is a simpler solution using _.difference():

const gameData = [{"Athlete":"Peyton Manning","Img":"url"},{"Athlete":"Tony Hawk","Img":"url"},{"Athlete":"Tom Brady","Img":"url"},{"Athlete":"Usain Bolt","Img":"url"},{"Athlete":"Kevin Durant","Img":"url"},{"Athlete":"Cristiano Ronaldo","Img":"url"},{"Athlete":"Michael Phelps","Img":"url"},{"Athlete":"Conor McGregor","Img":"url"},{"Athlete":"Phil Mickelson","Img":"url"},{"Athlete":"Stephen Curry","Img":"url"},{"Athlete":"Rory McIlroy","Img":"url"},{"Athlete":"Mike Trout","Img":"url"},{"Athlete":"Danica Patrick","Img":"url"},{"Athlete":"Drew Brees","Img":"url"},{"Athlete":"Carmelo Anthony","Img":"url"},{"Athlete":"Ryan Lochte","Img":"url"},{"Athlete":"Eli Manning","Img":"url"},{"Athlete":"Chris Paul","Img":"url"}];

const usedAthletes = ["Peyton Manning", "Tony Hawk", "Tom Brady"];

const result = _(gameData)
  .map('Athlete')
  .difference(usedAthletes)
  .value();

console.log(result);

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

edited Aug 1, 2017 at 18:02

answered Aug 1, 2017 at 17:31

Ori Drori

196k32 gold badges243 silver badges233 bronze badges

5 Comments

SirFry Over a year ago

This works too. I then mapped result to just an array of athletes. thanks!

Ori Drori Over a year ago

While you were jumping around accepting answers :) I've added a simpler solution for get an array of names.

SirFry Over a year ago

Thanks. I'm just making sure to look at all answers and make sure I understand why each one works and what they're doing. So I learn how to use things like filter or the lodash difference better!

Ori Drori Over a year ago

That's exactly what you should do - try and learn. It was just funny seeing the accept mark jumping around.

SirFry Over a year ago

haha yeah, I didn't realize I couldn't say more than one answer worked. It's not fair, everyone worked!

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