Introducing dplyr

According to the dplyr documentation at http://dplyr.tidyverse.org/, dplyr is a grammar of data manipulation, providing a consistent set of verbs that help you solve the most common data manipulation challenges, as follows:

• mutate(): Adds new variables that are functions of existing variables
• select(): Picks variables based on their names
• filter(): Picks cases based on their values
• summarize(): Reduces multiple values down to a single summary
• arrange(): Changes the ordering of the rows
• group_by(): Allows you to perform any operation by group

While each of the verbs corresponds to a particular function in dplyr, a verb can be thought of more generally as particular action that transform the data in a certain way.

Note

In addition to the verbs listed here, there is also functionality in dplyr that can be used to merge (or join) data from different sources though I won't be covering these features here.

In the following sections, I will demonstrate each of these functions individually...