Interlude (3)
What if you want all variables but only for the first 10 respondents? Yes, you could use cdc[1:10, 1:9], but that would mean you have to count the number of variables in our set. Fortunately, R makes it easy: if you want all rows or columns, you just leave it empty. So the former can be rewritten as cdc[1:10, ].
By leaving out an index or a range (as you didn't type anything between the comma and the square bracket), you get all the columns. When starting out in R, this is a bit counterintuitive. Similarly, if you leave out an index or range for the rows, you get all the observations. Typing cdc[, 6] will give you all the weights for all 20,000 respondents.
So yes, typing cdc[,] will simply give you the entire data frame cdc.
This exercise is part of the course
Data Analysis and Statistical Inference
Exercise instructions
- Assign all variables for the 205th respondent to
resp205. - Assign the variables height and weight for all respondents to
ht_wt.
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
resp205 <-
ht_wt <-
# Print the subsets
resp205
head(ht_wt)