Introduction to the workspace

Exploring the tableau prep builder interface

The Tableau Prep Builder interface and different sections of it is shown here.

How to connect your dataset with Tableau Prep

In order to connect Tableau Prep to a local dataset, click on Connect to Data button and choose your file type under the To a File section. The file types supported by Tableau Prep are:

  • Microsoft Access

  • PDF file

  • Microsoft Excel

  • Statistical file

  • Tableau extract

  • Text file

  • The COVID-19 dataset, that will be used in this materials, is a text file with the name us-counties.csv and after a successful opening by clicking on "Text file" button, you should see these information about the dataset.

  • Connections: shows the files or dataset/databases connected to the workspace.

  • Tables: shows the tables included in this dataset. The text files would have only one tables, but other data types such as the Microsoft Excel could contain more than one spreadsheet or have multiple tables.

  • Settings: you can define that the first line of the text file is contains the header or what is the separator type as well as text qualifier and character set in this section. For the loaded us-counties.csv file indeed the first line contains the headers and the separator for each column or field is a comma.

  • In the Data Sample section, we could define the sampling algorithm of the Tableau Prep.

  • It is possible to Use all data, which by definition would use all the rows available in your dataset.

  • This method would be slow for very large dataset. By default, Tableau Prep would load a certain number of rows from your dataset based on the number of fields available and their data type.

  • Also, it is possible to fix the number of rows to be loaded into the Tableau Prep. Finally, it is possible to enable random sampling.

In this materials, we choose Use all data option.

Ways of filtering and analyzing the information in the dataset

In order to choose certain rows in the dataset, filtering helps to identify them based on a certain condition. Click on Filter Values to open up the section for writing the condition for filtering.

  • Now, we want to write the condition for filtering here, which would be to choose only South Carolina state or in Tableau Prep syntax as:

[state] = 'South Carolina'

  • Then click on Apply to enforce this filtering.

  • All the changes made to the dataset could be seen, removed, or modified in the Changes section or in front of the field name that is changed.

The packaged flow created in this section is shared here for reproducibility: https://bit.ly/2Tucsu9