Interlude: How R thinks about data (1)
It was mentioned that R stores data in data frames, which you might think of as a type of spreadsheet. Each row is a different observation (a different respondent) and each column is a different variable (the first is genhlth, the second exerany and so on).
This means you can also retrieve values from our data frame using the indices (positions) of the rows and columns you want. For example, to see the sixth variable (which happens to be weight) of the 567th respondent, use the format cdc[567, 6]. This is called the row-and-column notation. Note that indices start at 1.
This exercise is part of the course
Data Analysis and Statistical Inference
Exercise instructions
- Assign the
heightof the 1337th respondent toheight_1337using the row-and-column notation. (Usenamesto see what the index ofheightis.) - Assign the
weightof the 111th respondent toweight_111using the row-and-column notation.
Hands-on interactive exercise
Have a go at this exercise by completing this sample code.
# The cdc data frame is already loaded into the workspace
# Create the subsets
height_1337 <-
weight_111 <-
# Print the results
height_1337
weight_111