Wow, that is a lot of cars!
Working with large data sets is not uncommon in data analysis. When you work with (extremely) large data sets and data frames, your first task as a data analyst is to develop a clear understanding of its structure and main elements. Therefore, it is often useful to show only a small part of the entire data set.
So how to do this in R? Well, the function head() enables you to show the first observations of a data frame. Similarly, the function tail() prints out the last observations in your data set.
Both head() and tail() print a top line called the 'header', which contains the names of the different variables in your data set.
Call head() on the mtcars data set to have a look at the header and the first observations.
# Call head() on mtcars
# Call head() on mtcars
head(mtcars)
test_function("head", "x", incorrect_msg = "Have you correctly passed `mtcars` to the `head()` function?")
test_output_contains("head(mtcars)", incorrect_msg = "Simply print out the result of the `head()` call, no need to assign it to a new variable.")
success_msg("Wonderful! So, what do we have in this data set? For example, `hp` represents the car's horsepower; the Datsun has the lowest horse power of the 6 cars that are displayed. For a full overview of the variables' meaning, type `?mtcars` in the console and read the help page. Continue to the next exercise!");
head(mtcars) will show the first observations of the mtcars data frame.