The team at RStudio have just released an update to the immensely useful dplyr package, making it even more powerful for manipulating data frame data in R. The new 0.4.0 version adds new "verbs" to the syntax for mutating joins (left join, right join, etc.), filtering joins, and set operations (intersection and union). There's also some new documentation to help you get started with dplyr, including a vignette on using data frames with dplyr and a printable cheatsheet on data wrangling with dplyr and tidyr. Check out all the updates at the RStudio blog post linked below.
RStudio blog: dplyr 0.4.0