R Tutorial: The filter and arrange verbs

Key Takeaways

you've learned how to select particular variables or columns that you're interested in now you'll explore the data to find interesting observations or rows we start with code for selecting four columns of interest the state county population and unemployment rate we could start by assigning that to the variable counties underscore selected will work with that variable from now on right now notice that the observations are in alphabetical order by state and county we might instead be interested in the counties that have the highest population the arranged verb sorts your data based on one or more variables you can start with your counties selected variable then the pipe operator then arranged inside the parentheses put population to specify the variable you want to sort by this shows us the counties with the lowest population which are indeed pretty small one county in Hawaii has only 85 people we might be more interested in the counties with the highest population to find these you change your code only a little bit add descending around population it looks like the highest population is Los Angeles California which is one of the biggest cities in the United States a range is thus a useful verb for finding the most interesting observations in the data set from now on we'll keep showing multiple verbs at a time to get you in the habit of typing many verbs together another useful verb is filter you can use the filter verb to extract only particular observations from a dataset based on a condition recall that after your first verb you can add a pipe operator then add another verb you can pipe any number of verbs together to transform your data set for example after the arranged you could add filters state equals equals quote New York to get only counties in the state of New York notice that the observations are filtered but they're still sorted by population thanks to your arranged besides equals equals you can filter based on logical operators like less than or greater than for example you could filter for counties that have an unemployment rate of less than 6% the condition in the filter would be unemployment less than 6 this tells you that the largest counties with an unemployment rate below 6% are Fairfax Virginia and Salt Lake Utah finally you can combine multiple conditions together in a filter you filtered for the state of New York and for unemployment below 6% but you can do both at the same time if you separate them with a comma it looks like only a few counties in New York have an unemployment rate that low throughout the court