How to turn a string onto a map?

Question

I need to turn a string formatted like that:

string = "John:31,Miranda:28"

Onto this;

obj = { "John" => 31, "Miranda" => 28 }

I did this :

const class = new Map();
array = string.split(",");

And obviously I do not know what do with it because after the split I get something like this:

["John:31", "Miranda:28"]

And I don't know how to turn it onto an object (using the ":" as a arrow)... Maybe I don't need to use the array as an intermediary? Any thoughts? Thanks

what is with the arrows in the object? That is fat arrow syntax..... Do you actually want it to be functions? — epascarello, Aug 04 '19 at 15:54

T.J. Crowder · Accepted Answer · 2019-08-04T15:59:12.370

You can use split to split by comma, and then map on the resulting strings to split again by colon, and feed the resulting array of arrays into the Map constructor.

For instance, if you want the map keyed by the names, which I suspect you do:

const string = "John:31,Miranda:28"
const map = new Map(string.split(",").map(entry => entry.split(":")));
console.log(map.get("John")); // "31" (a string)

If you want the numbers to be numbers, not strings, you'll need to convert them:

const string = "John:31,Miranda:28"
const map = new Map(string.split(",").map(entry => {
    const parts = entry.split(":");
    parts[1] = +parts[1];
    return parts;
}));
console.log(map.get("John")); // 31 (a number)

My answer here goes into some detail on your options for converting from string to number.

If you want the map keyed by value instead (which I suspect you don't, but...), you just have to reverse the order of the inner array entries:

const string = "John:31,Miranda:28"
const map = new Map(string.split(",").map(entry => {
    const [name, num] = entry.split(":");
    return [num, name];
}));
console.log(map.get("31")); // John

It works; but I need to turn the value from a string to an integer... any idea? — , Aug 04 '19 at 15:58
@JeanhDev - Heh, I guessed you might, and *just* updated the answer... :-) — T.J. Crowder, Aug 04 '19 at 15:59
Thank you so much! such a comprehensive and complete answer! have a great day :) — , Aug 04 '19 at 16:01

Joss Classey · Answer 2 · 2019-08-04T16:04:47.910

0

You could try something like this:

const data = "John:31,Miranda:28"

const splitData = data.split(',')

const result = splitData.reduce((newObject, item) => {
  const [name, age] = item.split(':')
  return {
    ...newObject,
    [name]: parseInt(age)
  }
}, {})

console.log(result)

edited Aug 04 '19 at 16:04

answered Aug 04 '19 at 15:57

Joss Classey

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score 0 · Answer 3 · answered Aug 04 '19 at 15:58

So split on the commas, loop over it and split on the colon, and build the object.

var myString = "John:31,Miranda:28"
var myObj = myString.split(',').reduce(function (obj, part) {
  var pieces = part.split(':')
  obj[pieces[0]] = pieces[1]
  return obj
}, {})

score 0 · Answer 4 · answered Aug 04 '19 at 16:25

I'll just add this here:

Basically, split string by the comma, then the colon.
Combine result into a map

const test = "John:31,Miranda:28"; 
console.log(test);
const obj = test.split(/,/).map(item => item.split(/:/));
console.log(obj);
const _map = new Map(obj);
console.log(_map);
console.log(_map.get("John"))

How to turn a string onto a map?

4 Answers4