Merging data with dplyr

In a SQL operation, we can perform a join operation to combine two different datasets. In dplyr, we have the same join operation that enables us to merge data easily. In this recipe, we explain how join works in dplyr.

Getting ready

Ensure that you completed the Enhancing a data.frame with a data.table recipe to load purchase_view.tab and purchase_order.tab as both data.frame and data.table into your R environment.

How to do it…

Perform the following steps to merge data with dplyr:

1. First, we generate a product.dt data table by calculating the amount of purchased items:

   > product.dt <- order.dt[,.(Buy = length(Action)),by=Product]
   > head(product.dt[order(-Buy)])
             Product Buy
   1:    P0005772981 821
   2:    P0024239865 729
   3:    P0004607050 584
   4:    P0003425855 552
   5:    P0014252066 438
   6: P0006587250014 357
   

2. Next, we can calculate the number of views by product, and put the calculation result into view.dt:

   > view.dt <- purchase.dt[, .(n_views = length...