Mapping an array to a object with lodash

Question

I have this array:

[ [ '2018-05-28T21:51:00Z',
    0.00000858,
    0.00000857,
    0.00000860,
    0.00000855,
    12511.81490226 ],
  [ '2018-05-28T21:52:00Z',
    0.00000853,
    0.00000850,
    0.00000856,
    0.00000847,
    12687.20140187 ],
  [ '2018-05-28T21:53:00Z',
    0.00000848,
    0.00000847,
    0.00000850,
    0.00000846,
    12708.9320888 ]
]

And i need to transform it to this:

{ 
    T: [ '2018-05-28T21:51:00Z', '2018-05-28T21:52:00Z', '2018-05-28T21:53:00Z' ],
    O: [ 0.00000858, 0.00000853, 0.00000848],
    C: [ 0.00000857, 0.00000850, 0.00000847],
    H: [ 0.00000860, 0.00000856, 0.00000850],
    L: [ 0.00000855, 0.00000847, 0.00000846],
    V: [ 12511.81490226, 12687.20140187, 12708.9320888 ]
}

It's predefined places, the first values is always 'T', the second values is always 'O' and so on.

Tried with lodash like this

_.zipObject(['T', 'O', 'H', 'L', 'C'], s.values)

But the results are not the expected. Some advices?

CertainPerformance · Accepted Answer · 2018-05-29 22:04:43Z

3

No need for a library, you can accomplish this easily with plain Javascript:

const input=[['2018-05-28T21:51:00Z',0.00000858,0.00000857,0.00000860,0.00000855,12511.81490226],['2018-05-28T21:52:00Z',0.00000853,0.00000850,0.00000856,0.00000847,12687.20140187],['2018-05-28T21:53:00Z',0.00000848,0.00000847,0.00000850,0.00000846,12708.9320888]]
const keys = ['T', 'O', 'C', 'H', 'L', 'V'];
const arrs = input.reduce((accum, item) => {
  keys.forEach((key, i) => accum[key].push(item[i]));
  return accum;
}, keys.reduce((a, key) => { a[key] = []; return a }, {}));
console.log(arrs);

answered May 29, 2018 at 22:04

CertainPerformance

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Henri Benoit · Accepted Answer · 2018-05-29 22:11:16Z

2

You can do it by just using zip and zipobject:

var input = [ [ '2018-05-28T21:51:00Z',
    0.00000858,
    0.00000857,
    0.00000860,
    0.00000855,
    12511.81490226 ],
  [ '2018-05-28T21:52:00Z',
    0.00000853,
    0.00000850,
    0.00000856,
    0.00000847,
    12687.20140187 ],
  [ '2018-05-28T21:53:00Z',
    0.00000848,
    0.00000847,
    0.00000850,
    0.00000846,
    12708.9320888 ]
];

var output = _.zipObject(['T', 'O', 'H', 'L', 'C'], _.zip.apply(_, input));

<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/1.2.1/lodash.min.js"></script>

answered May 29, 2018 at 22:11

Henri Benoit

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Comments

obey · Accepted Answer · 2018-05-29 22:10:31Z

0

You can achieve this by doing so:

const trans  = data[0].map((col, i) => data.map(row => row[i]));

_.zipObject(['T', 'O', 'H', 'L', 'C'], trans)

data is your initial array.

answered May 29, 2018 at 22:10

obey

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