Today was the first time I ever opened Tableau Prep ever, it was intimidating at first but Carl's amazing tangents helped me wrap my head around the new concepts!
Tableau Prep:
Tableau Prep is used to clean and reshape data so we can analyze and communicate it. Fields represent a column in the dataset whereas, a row is one single instance of information. The fields can contain different datatypes including; strings, integers, Booleans, date etc. In this case, we compare measures and categories e.g. number of sales to products - granularity explains how detailed the dataset is.
Planning:
Planning can be very time efficient before trying to jump into the dataset and clean it. Identifying datatypes, fields and rows helps you understand what you want your cleaned up data to look like (this includes splitting fields into measures and categories). The best way to plan in my opinion is to make a check list of what needs to be done conceptually.
Using Tableau Prep:
This was the most difficult part of the day, understanding technical concepts. Completing the Tableau Prep challenges is a good chance to get first hand experience rather than just reading about all the steps that you can do. Using a dataset on weather in different cities, we identified that:
- City field needs to cleaned (group similar spelling)
- Pivot to turn min/max temp into fields
- Merge metric and measures (adding units)
- Adjusting data types (string to date)
Having a check list like this helps with not getting overwhelmed. The one element I really could not understand was Aggregation. To put it simply, it is the concept of grouping categories to view certain measures, summarizing the data. You can also view the average or total measures using the aggregate step. Branching off of the first cleaning step is also useful to save time and prevents unnecessary steps being made. Once the cleaning and reshaping is done you can output (which I forgot to do in one of the challenges) and save the file and flow.
Summary:
A) Plan using a checklist
B) Understand all the steps you can do in Tableau Prep
C) Remember to output!