Exercise

Accessing and subsetting data frames (1)

Even more often than with vectors, you are going to want to subset your data frame or access certain columns. Again, one of the ways to do this is to use [ ]. The notation is just like matrices! Here are some examples:

Select the first row: cash[1, ]

Select the first column: cash[ ,1]

Select the first column by name: cash[ ,"company"]

Instructions

100 XP

Select the third row and second column of cash.
Select the fifth row of the "year" column of cash.