Merge/flatten multidimensional array and remove duplicates Javascript

Question

I have a multidimensional array that looks like this:

var workouts = [
  [0, Object, 0, 0, 0],
  [Object, 0, 0, 0, 0],
  [0, 0, 0, Object, 0]
];

I'd like to flatten/merge the array and remove the duplicates. The result should look something like this:

[Object, Object, 0, Object, 0]

Is it possible to perform?

How are you defining removing duplicates? Why is 0 in your result twice, is that not a duplicate? What have you tried? — UnknownFury
– UnknownFury, Commented Aug 11, 2016 at 10:49
only 2 zeroes are there in your expected Output.. Is that right? It supposed to have 3 zeroes isn't it? — Rajaprabhu Aravindasamy
– Rajaprabhu Aravindasamy, Commented Aug 11, 2016 at 10:51
Yes, it should be 2 zeros in the expected output. My plan is to loop the expected output and then render different elements depending on the 0 / the object. — malen
– malen, Commented Aug 11, 2016 at 10:55
Are you mapping the indices of inner arrays and mark the ones with the object if an inner array has an onbect at that index or 0 if not? — Redu
– Redu, Commented Aug 11, 2016 at 11:00

Arnauld · Accepted Answer · 2016-08-11 10:58:41Z

2

My understanding is that you want to keep the first encountered object in a given column if it exists.

You can do that with .map() and .reduce():

var workouts = [
  [0, {id:1}, 0, 0, 0],
  [{id:2}, 0, 0, 0, 0],
  [0, 0, 0, {id:3}, 0]
];

var res = workouts.reduce(function(a, b) {
  return b.map(function(e, i) { return a[i] instanceof Object ? a[i] : e; });
}, []);


console.log(JSON.stringify(res));

answered Aug 11, 2016 at 10:58

Arnauld

6,1882 gold badges17 silver badges34 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

vahdet · Accepted Answer · 2019-12-09 14:32:05Z

2

Late for the party, but I still want to make use of:

Array.prototype.flat() for reducing the dimension to 1,
Set for removing dupes
Spread Syntax for getting array out of that set.
JSON.stringify and parse back for handling dupes of Objects.

Here's the code and a very inspirational posts 1 and 2:

const myArray = [
  [0, {id:1}, 0, 0, 0],
  [{id:2}, 0, 0, 0, 0],
  [0, 0, 0, {id:2}, 0]
]

const myFlatArray = myArray.flat()
const result = [...new Set(myFlatArray.map(JSON.stringify))].map(JSON.parse)

console.log(JSON.stringify(result))

Note: ES6 must be supported for this solution

answered Dec 9, 2019 at 14:32

vahdet

6,78910 gold badges62 silver badges116 bronze badges

Comments

charsi · Accepted Answer · 2016-08-11 11:04:33Z

0

var workouts = [
  [0, {id:1}, 0, 0, 0],
  [{id:2}, 0, 0, 0, 0],
  [0, 0, 0, {id:3}, 0]
];

function flattenArray (array){
  var newArray = [];
  for (i=0; i<array.length; i++){
    var subArray = array[i];
    for (ii=0; ii<subArray.length; ii++){
      if (newArray.indexOf(subArray[ii]) == -1){
      newArray.push(subArray[ii]);
      }
    }
  }
  return newArray;
}
console.log(flattenArray(workouts));

http://codepen.io/anon/pen/WxLrqL

answered Aug 11, 2016 at 11:04

charsi

4,14728 silver badges44 bronze badges

Comments

Redu · Accepted Answer · 2016-08-11 11:08:55Z

0

I would do like this;

var workouts = [[0, {a:1}, 0, 0, 0],
                [{b:2}, 0, 0, 0, 0],
                [0, 0, 0, {c:3}, 0]
               ],
      result = workouts.reduce((p,c) => p = c.map((e,i) => e || p[i] || 0 ),[])
console.log(result);

answered Aug 11, 2016 at 11:08

Redu

26.3k6 gold badges61 silver badges84 bronze badges

1 Comment

Piotr Kula Over a year ago

I don't understand anything :( all the inline code and non explanatory variables makes its super hard to read

Collectives™ on Stack Overflow

Merge/flatten multidimensional array and remove duplicates Javascript

4 Answers 4

Comments

Comments

Comments

1 Comment

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

4 Answers 4

Comments

Comments

Comments

1 Comment

Your Answer

Sign up or log in

Post as a guest

Linked

Related