I have the following arrays:
var a = ["F", "M"];
var b = ["female", "male"];
var c = ["fa-female", "fa-male"];
and I am able to assign b to a using for loop with:
ans[a[i]] = values[i]; // { M: "male", F: "female" }
how would I go about adding the third array and assign it to a as well?
{ M: {"male", "fa-male"}, F: {"female", "fa-female"} }
or something similar?
EDIT: Result could either be an array or an object.
Using Object.fromEntries(), you can build an array of [key, value] pairs by mapping (.map()) each key (ie: value) from a to an array of values from the same index from all the other arrays:
const a = ["F", "M"];
const b = ["female", "male"];
const c = ["fa-female", "fa-male"];
const buildObj = (keys, ...values) => Object.fromEntries(keys.map(
(key, i) => [key, values.map(arr => arr[i])]
));
const res = buildObj(a, b, c);
console.log(res);Object.fromEntries() has limited browser support, however, it can easily be polyfilled. Alternatively, instead of using an object, you could use a Map, which would remove the need of .fromEntries():
const a = ["F", "M"];
const b = ["female", "male"];
const c = ["fa-female", "fa-male"];
const buildMap = (keys, ...values) => new Map(keys.map(
(key, i) => [key, values.map(arr => arr[i])]
));
const res = buildMap(a, b, c);
console.log("See browser console:", res); // see browser console for output
var resultArray = []; to var resultArray = {}; if you're going to use the accepted answer as you really want an object as your output ;)
Object.fromEntries is definitely the way to go IMHO, so +1. It's a shame it doesn't provide a function for handling collision.
fromEntries method. It's important to note the enumerable nature to using object {} budji. object.key or object[key].You could combine your arrays to form key/value pairs for Object.fromEntries:
Object.fromEntries([['M', 'male'], ['F', 'female']]);
//=> {M: 'male', F: 'female'}
However Object.fromEntries does not handle collisions:
Object.fromEntries([['M', 'male'], ['F', 'female'], ['F', 'fa-female']]);
//=> {M: 'male', F: 'fa-female'}
As you can see, the previous value for F just got overridden :/
We can build a custom fromEntries function that puts values into arrays:
const fromEntries =
pairs =>
pairs.reduce((obj, [k, v]) => ({
...obj,
[k]: k in obj
? [].concat(obj[k], v)
: [v]
}), {});
fromEntries([['M', 'male'], ['M', 'fa-male'], ['F', 'female'], ['F', 'fa-female']]);
//=> {M: ["male", "fa-male"], F: ["female", "fa-female"]}
How do you create key/value pairs then?
One possible solution: zip
const zip = (x, y) => x.map((v, i) => [v, y[i]]);
zip(['F', 'M'], ['female', 'male']);
//=> [["F", "female"], ["M", "male"]]
So to produce all pairs (and your final object)
fromEntries([
...zip(['F', 'M'], ['female', 'male']),
...zip(['F', 'M'], ['fa-female', 'fa-male'])
]);
use this one.
var a = ["F", "M"];
var b = ["female", "male"];
var c = ["fa-female", "fa-male"];
var resultArray = [];
for(var i = 0; i < a.length; i++) {
resultArray [a[i]] = [b[i], c[i]];
}
var resultObject = Object.assign({});.. same loop for assignment. difference would be type handling on resultObject with enumeration and property accessor support. i.e. resultObject.m or resultObject["m"], and the enumeration for(key in resultObject) resultObject[key] var a = ["male","female"];
var b = ["m","f"];
var c = ["fa male","fa female"];
var result = a.reduce((res,val,key) => {
var temp = [b,c];
res[val] = temp.map((v) => v[key]);
return res;
},{});
This is bit expensive. It is a nested loop.
Here is one line with forEach. Another way using reduce and Map.
var a = ["F", "M"];
var b = ["female", "male"];
var c = ["fa-female", "fa-male"];
const ans = {};
a.forEach((key, i) => (ans[key] = [b[i], c[i]]));
console.log(ans)
// Alternate way
var ans2 = Object.fromEntries(
a.reduce((acc, curr, i) => acc.set(curr, [b[i], c[i]]), new Map())
);
console.log(ans2);
A solution using map and filter
var a = ["M", "F"];
var b = ["female", "male"];
var c = ["fa-female", "fa-male"];
const bAndC = b.concat(c);
let returnObj = {};
a.map(category => {
let catArray = []
if(category === 'F') {
catArray = bAndC.filter(item => item.includes('female'));
} else {
catArray = bAndC.filter(item => item.includes('male') && !item.includes('female'));
}
return returnObj[category] = catArray;
});
