Database CSV (Data Frames)
Throughout this course we will slowly build on integrating database management with R coding. The first and most basic way to get data from your database into R is to export it from the database and then import it into R.
Download a new copy
of the portal_mammals.sqlite database. Using the SQLite Manager, write a query
to extract the year of capture, genus, species, and weight of the 500 largest
individuals captured at the site. Save your query as a View and export it to as
a csv file using the Export Wizard. You can initiate the Export Wizard by
clicking on the view’s Structure tab and choosing Export or by selecting
Export View from either the View menu or the right click menu for the
view. You should check the First row contains column names box so that it is
clear what is in your exported file, and save the file as
500-Largest-Individuals.csv in your working directory.
Import the 500-Largest-Individuals.csv file into R and complete the following
tasks:
- Use
str()to show the structure of the data frame and its individual columns - Use the
unique()function to print the genus and the species for each species represented in the 500 largest individuals sampled. - Use the
nrow()andunique()functions to determine how many years are represented in this dataset. - Use the
min()andmax()functions to check how much smaller (as a percent) the 500th largest individual is than the largest (i.e., (max - min) / max * 100). - Calculate the average size of a Neotoma Albigula in this dataset.