Merge several arrays into a single array using an algorithm

Question

Merge several arrays into a single array using an algorithm

Hey everyone, I'm facing a little problem here.

Basically, I have this object that contains 3 arrays...

items = {
    a: ['STRAWBERRY', 'PEANUT'],
    b: ['John', 'Doe', 'Scarface'],
    c: ['Circle', 'Square', 'Triangle', 'Rectangle'],
}

What I'm looking for is this specific output:

[
    'STRAWBERRY',
    'John',
    'Circle',
    'PEANUT',
    'Doe',
    'Square',
    'Scarface',
    'Triangle',
    'Rectangle'
]

IMPORTANT NOTE: THE OUTPUT NEEDS TO INTERLEAVE BETWEEN EACH VALUE OF THE ARRAYS INSIDE THE 'ITEMS' OBJECT

I've been trying to come up with an efficient way to achieve this without having to write a massive amount of code full of loops.

Does anyone know of a quick and optimized solution for this?

P.S.: I am open to using any available framework.

UPDATE Thanks to @evillive's response, I managed to adapt the approach into CoffeeScript

SOLUTION USING COFFEE SCRIPT

result = []
col = -1
loop
  col++
  run = false
  for k of Items
    Items[k][col] and (run = result.push(Items[k][col]))
  unless run
    break

console.log result

javascript arrays merge

Answer 1

Answer №1

If you want to maintain the order, follow these steps: http://jsfiddle.net/o5k965ze/

var items = {
    a: ['STRAWBERRY', 'PEANUT'],
    b: ['John', 'Doe', 'Scarface'],
    c: ['Circle', 'Square', 'Triangle', 'Rectangle'],
};

function getLength (obj) {
    var length = 0;
    for (var key in obj) {
        if (obj.hasOwnProperty(key)) {
            if (obj[key].length > length) {
                length = obj[key].length;
            }
        }
    }
    return length;
}

function merge () {
    var newArray = [];
    var length = getLength(items);
    console.log(length);
    var index = 0;
    for ( ; index < length; index++) {
        for (var key in items) {
            if (items[key][index]) {
                newArray.push(items[key][index]);
            }
        }
    }
    console.log(newArray)
}

merge();

Using this method will ensure that you achieve the desired order, even when working with more than three arrays in the object.

Answer 2

If you want to maintain the order, follow these steps: http://jsfiddle.net/o5k965ze/

var items = {
    a: ['STRAWBERRY', 'PEANUT'],
    b: ['John', 'Doe', 'Scarface'],
    c: ['Circle', 'Square', 'Triangle', 'Rectangle'],
};

function getLength (obj) {
    var length = 0;
    for (var key in obj) {
        if (obj.hasOwnProperty(key)) {
            if (obj[key].length > length) {
                length = obj[key].length;
            }
        }
    }
    return length;
}

function merge () {
    var newArray = [];
    var length = getLength(items);
    console.log(length);
    var index = 0;
    for ( ; index < length; index++) {
        for (var key in items) {
            if (items[key][index]) {
                newArray.push(items[key][index]);
            }
        }
    }
    console.log(newArray)
}

merge();

Using this method will ensure that you achieve the desired order, even when working with more than three arrays in the object.

Answer 3

Answer №2

In this solution, there is no need to specify a maximum length parameter for the lookup process.

var result = [];
while(Object.getOwnPropertyNames(items).length){
  for(var k in items){
    result.push(items[k].shift());
    if (items[k].length == 0) delete items[k];
  }
}

UPDATE: After realizing that using shift and delete impacts performance negatively, I have rewritten the code to optimize its speed significantly.

var result = [], col = -1, run;
do {
    col++; run = false;
    for(var k in items){
        items[k][col] && (run = result.push(items[k][col]))
    }
} while(run)

Answer 4

In this solution, there is no need to specify a maximum length parameter for the lookup process.

var result = [];
while(Object.getOwnPropertyNames(items).length){
  for(var k in items){
    result.push(items[k].shift());
    if (items[k].length == 0) delete items[k];
  }
}

UPDATE: After realizing that using shift and delete impacts performance negatively, I have rewritten the code to optimize its speed significantly.

var result = [], col = -1, run;
do {
    col++; run = false;
    for(var k in items){
        items[k][col] && (run = result.push(items[k][col]))
    }
} while(run)

Answer 5

Answer №3

With the power of lodash, you can easily achieve this:

_.flattenDeep(_.values(list));

Answer 6

With the power of lodash, you can easily achieve this:

_.flattenDeep(_.values(list));

Answer 7

Answer №4

let Objects = {
  x: ['APPLE', 'BANANA'],
  y: ['Alice', 'Bob', 'Cindy'],
  z: ['Circle', 'Square', 'Triangle', 'Rectangle'],
};
let totalLength = 0;
let currentIndex = 0;
let finalOutput = [];

for (let key in Objects) {
  totalLength = Math.max(totalLength, Objects[key].length);
}

if (!totalLength) return finalOutput;

for (currentIndex; currentIndex < totalLength; currentIndex++) {
  for (let key in Objects) {
    let objectItem = Objects[key][currentIndex];
    objectItem && finalOutput.push(objectItem);
  }
}

return finalOutput;

Answer 8

let Objects = {
  x: ['APPLE', 'BANANA'],
  y: ['Alice', 'Bob', 'Cindy'],
  z: ['Circle', 'Square', 'Triangle', 'Rectangle'],
};
let totalLength = 0;
let currentIndex = 0;
let finalOutput = [];

for (let key in Objects) {
  totalLength = Math.max(totalLength, Objects[key].length);
}

if (!totalLength) return finalOutput;

for (currentIndex; currentIndex < totalLength; currentIndex++) {
  for (let key in Objects) {
    let objectItem = Objects[key][currentIndex];
    objectItem && finalOutput.push(objectItem);
  }
}

return finalOutput;

Merge several arrays into a single array using an algorithm

Answer №1

Answer №2

Answer №3

Answer №4

Similar questions

What is the best way to display two radio buttons side by side in HTML?

MongoDB aggregation function returning zero rather than the correct sum of numbers within an array

Error message: The function pokemon.map does not exist

What is the method for utilizing string interpolation in Angular/Typescript in order to retrieve a value from a variable?

Having trouble receiving values sent through AJAX POST requests to PHP

React: Struggling to render values within {} of a multidimensional object

Vue project encounters disappeared DOM element

Implementing a Dropdown Menu Within a React Form

Delay in displaying Promise API call in NextJS

Increase and decrease buttons using the 'keydown' event (ArrowUp and ArrowDown)

Set a character to an array of characters within a structure that is nested inside an array of structures, which in turn is nested inside another array of structures within a final array

How can I locate a specific car brand within the car index I compiled earlier?

Incorporating a rigged and animated asset into a preexisting scene using Three.js

Utilizing local storage, store and access user's preferred layout options through a click function

The functionality of $watch is not functioning correctly within the Modal, despite implementing it with $scope.user={pwd1:''}

JavaScript: An object containing a unified handler for all method invocations

Error: CSS and JavaScript files cannot be found

Error: The function Stripe.customers.cancel is not recognized in Stripe version 14.18.0

What is the method for creating a new array of objects in Typescript with no initial elements?

Angular Resolution Verification