Selection of data frame elements (2)
Instead of using numerics to select elements of a data frame, you can also use the variable names to select columns of a data frame.
Suppose you want to select the first three elements of the type column. One way to do this is
planets_df[1:3,2]
A possible disadvantage of this approach is that you have to know (or look up) the column number of type, which gets hard if you have a lot of variables. It is often easier to just make use of the variable name:
planets_df[1:3,"type"]
This exercise is part of the course
Introduction to R
Exercise instructions
Select and print out the first 5 values in the "diameter" column of planets_df.
Hands-on interactive exercise
Have a go at this exercise by completing this sample code.
# The planets_df data frame from the previous exercise is pre-loaded
# Select first 5 values of diameter column