Join datasets

- Data is inherently messy.…And in this next challenge,…our instructor has to clean it up.…Datasets are stored in different formats.…Sometimes as flat files with simple rows…and column relationships.…Sometimes as key value pairs…as found in JSON or XML files.…Sometimes data is stored and distributed…with built-in relationships.…These are often found in SQL files.…To make things more complex,…data is also stored in various formats.…

For example, sometimes dates are stored as strings,…other times as the number of seconds…since January 1st, 1970…also known as the Epoch.…Numbers can be stored as strings, integers, or floats.…Locations can be represented as longitude and latitude…or it can defined as zip code, county,…or a magnitude of other formats.…Because of this, datasets often need to be reformatted.…Data scientists refer to this…as the Extract, Transform, and Load process or ETL.…

Extraction is the simple operation of opening a data file.…The instructor did this in the previous chapter.…Transform is the process of converting data…