change order of array based on another array

Question

Let say we have our array like this:

let myArray = ["A", "B", "C", "D"]

What if we want to modify the order of elements in myArray based on modifier array so that, if myArray includes any element of modifier then we send that element to the end of the myArray

Like this:

let modifier =  ["B"] 
myArray = ["A", "C", "D", "B"] // B is sent to the end of myArray

And if we have this:

let modifier =  ["A", "C"]
myArray = ["B", "D", "A", "C"] // A and C are sent to the end of the array

I have tried looping and checking each array element against another but it went complicated...

Any help would be greatly appreciated.

Bilal Siddiqui · Accepted Answer · 2019-10-05 10:31:07Z

3

Very simple.

Step-1: Remove elements of modifier array from original array

 myArray = myArray.filter( (el) => !modifier.includes(el) );

Step-2: Push modifier array into original array

myArray = myArray.concat(modifier)

Update

As per demands in comments by seniors :) If use case is to move multiple data:

var myArray = ["A", "A", "A", "B", "B", "B", "C", "D", "E"];
var modifier = ["A", "B"];

// get static part
staticArray = myArray.filter( (el) => !modifier.includes(el) );

// get moving part
moveableArray = myArray.filter( (el) => modifier.includes(el) );

// merge both to get final array
myArray = staticArray.concat(moveableArray);

console.log(myArray);

edited Oct 5, 2019 at 10:31

answered Oct 5, 2019 at 9:14

Bilal Siddiqui

3,6491 gold badge16 silver badges22 bronze badges

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

3 Comments

Bilal Siddiqui Over a year ago

@JonasWilms what is your use case ? Please provide an example.

georg Over a year ago

e.g. array=AAABBBCDE, modifier=AB

Bilal Siddiqui Over a year ago

@georg : I have updated my answer with your use case as well.

Nina Scholz · Accepted Answer · 2019-10-05 09:19:50Z

3

You could sort the array and move the items of modifier to the end of the array.

function sort(array, lastValues) {
    var last = Object.fromEntries(lastValues.map((v, i) => [v, i + 1]));
    return array.sort((a, b) => (last[a] || - Infinity) - (last[b] || - Infinity));
}

var array = ["A", "B", "C", "D"];

console.log(...sort(array, ["B"]));
console.log(...sort(array, ["A", "C"]));

answered Oct 5, 2019 at 9:19

Nina Scholz

388k26 gold badges367 silver badges417 bronze badges

1 Comment

georg Over a year ago

Fun fact: Infinity-Infinity = NaN. Since you already do i+1, why not just 0?

Abhishek Tiwari · Accepted Answer · 2019-10-05 09:29:32Z

1

Simply use this to get desired result

    let myArray = ["A", "B", "C", "D"];
let modifier =  ["A", "C"];

for(let i=0;i<modifier.length;i++){
   if(myArray.includes(modifier[i])){
     myArray.splice(myArray.indexOf(modifier[i]), modifier[i]);
     myArray.push(modifier[i]);
   }
}
console.log(myArray);

answered Oct 5, 2019 at 9:29

Abhishek Tiwari

1437 bronze badges

Collectives™ on Stack Overflow

change order of array based on another array

3 Answers 3

3 Comments

1 Comment

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

3 Comments

1 Comment

Comments

Your Answer

Sign up or log in

Post as a guest

Related