R Tutorial: The arrange verb

Want to learn more? Take the full course at https://learn.datacamp.com/courses/introduction-to-the-tidyverse at your own pace. More than a video, you'll learn hands-on coding & quickly apply skills to your daily work. --- In the last video, you learned the filter verb, for extracting a subset of your observations based on a condition. Now you'll learn the arrange verb. arrange sorts the observations in a dataset, in ascending or descending order based on one of its variables. This is useful, for example, when you want to know the most extreme values in a dataset. Just like filter, you use the arrange verb after the pipe operator. You would type gapminder, then the pipe operator- percent, greater than, percent- and then arrange. Within those parentheses, you tell it what column you want to arrange by. The observations are now sorted in ascending order, with the lowest GDP per capita appearing first. Look at the rightmost column: notice that it starts with 241, the smallest value in the dataset, then keeps increasing. You can see that the country-year pair with the lowest GDP per capita was the Democratic Republic of the Congo in 2002. Just like with filter, the gapminder object itself is unchanged: arrange is just giving you a new, sorted dataset. Arrange also lets you sort in descending order. To do that, you'd put the D-E-S-C- for descending- around the variable you're sorting by. This lets us see that the country-year pair with the highest GDP per capita was Kuwait in the year 1957. Looking across all countries and all years might not be that useful. Suppose you wanted to find the highest GDP-per-capita countries in just one year. To do that, you can combine the two verbs you've already learned: filter, and arrange. You start with the gapminder dataset, then a pipe to give the dataset to filter. Then you specify that you want to filter for year equals equals 2007. Then you use another pipe. This takes the result of the filter, and gives it to arrange. Yo