We will begin with type conversions because you cannot create properly functioning calculated fields without having the fields in the right format. For instance, aggregations work on numeric fields, string functions work on strings, and date functions work on dates. Tableau Public automatically identifies the type of field based on its contents, but this may not meet your needs to aggregate or create calculations. Publicly available data sources, such as the ones available at http://public.tableau.com/s/resources, often have issues with either the format or the quality of the data. This will make it necessary for you to convert fields into different types, and it is quite likely that you will need to strip bad data and identify replacement values as well.
If you are familiar with relational database management, you are probably aware that there are many different field types, some of which are used to govern the field length within a database. Tableau Public focuses on the...
