Practice: Data Tables

Exercises

1. How can you tell if an object is a tibble? (Hint: try printing mtcars, which is a regular data frame).

2. Compare and contrast the following operations on a data.frame and equivalent tibble. What is different? Why might the default data frame behaviours cause you frustration?

   df <- data.frame(abc = 1, xyz = "a")
   df$x
   df[, "xyz"]
   df[, c("abc", "xyz")]

3. If you have the name of a variable stored in an object, e.g. var <- "mpg", how can you extract the reference variable from a tibble?

4. Practice referring to non-syntactic names in the following data frame by:

   1. Extracting the variable called 1.

   2. Plotting a scatterplot of 1 vs 2.

   3. Creating a new column called 3 which is 2 divided by 1.

   4. Renaming the columns to one, two and three.

   annoying <- tibble(
     `1` = 1:10,
     `2` = `1` * 2 + rnorm(length(`1`))
   )

5. What does tibble::enframe() do? When might you use it?

6. What option controls how many additional column names are printed at the footer of a tibble?

Source: H. Wickham and G. Grolemund, https://r4ds.had.co.nz/tibbles.html
This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.