dplyr Databases

Source and Query

This is a follow up to the Basic Queries filtering problem.

It is clear Dr. Undómiel appreciates your skill working with large databases and she seems to expect you will maintain your benevolence. (Such is a fair expectation of a true wizard). This time though, she’s looking for some extra detail in her queries. She’s curious if desert rodents are dimorphic in size.

1. Download a new copy of the Portal database.
2. Connect to portal_mammals.sqlite as object portaldb using dplyr.
3. Start by reminding yourself about which tables are in the database using src_tbls()
4. Then remind yourself of the fields in the surveys and plots tables using the list subset operator $ops$vars.
5. Select and print out the average hind foot length and average weight of:
   • all Dipodomys spectabilis individuals on the control plots
   • male D. spectabilis on the control plots
   • female D. spectabilis on the control plots

[click here for output]