goz / data-engineer-interview

Do you have what it takes to be an Avant data engineer?

Data Engineering Recombinator Challenge

If you stumbled on this challenge and enjoyed trying it, feel free to send a note over to [email protected] and talk directly to the director of data science. We're constantly chatting with awesome developers. Even if you're purely into open source... if you think playing with data is cool we think you're cool.

Context

Being able to easily manipulate data (aka munging) is an important part of our day-to-day here at Avant. Please write a small CLI tool that works as described below. You may use the language of your choice.

Input

Your program should expect valid JSON representing a two dimensional matrix. It will be in one of the following two formats:

A) a list of lists

The expected format is [ [variable names], [first row], [second row], ... ]

recombinator '[ ["a","b","c"], [1,2,null], [null,3,4], [5,null,6] ]'

B) a list of objects

JSON objects are simply unordered collections of key:value pairs.

Each row is represented by an object containing the variables set for that row.

Accordingly, this form of input is convenient for sparse data sets.

recombinator '[ { "a":1, "b":2 }, { "b":3, "c":4 }, { "c":6, "a":5 } ]'

Output

Your program should transform the input into a single JSON object mapping variable names to lists of values.

For input type (B), any variables that are missing in a row should be imputed with null.

The order of the values in each variable's list should be the same as the order of the rows.

'{ "a": [1,null,5], "b": [2,3,null], "c": [null,4,6] }'