Dive into dplyr (tutorial)

Data Manipulation Using R (& dplyr) by Ram Narasimhan, PDF slides

Data Manipulation with dplyr brief tutorial

Aggregating and analyzing data with dplyr tutorial by Data Carpentry

Introduction to dplyr for Faster Data Manipulation in R tutorial and a 40 min video Hands-on dplyr tutorial for faster data manipulation in R

Animations of tidyverse verbs using R, the tidyverse, and gganimate - visual explanation of dplyr operations

Pivoting, reformatting data into long/wide formats

A graphical introduction to tidyr’s pivot

Reusing Tidyverse code - dplyr/tidyverse data manipulation lecture slides

What is the difference between read_xls() and read_xlsx() functions? What message do you get if reading an .xlsx file using read_xls() function?

What does the skip argument do?

Do we need to refer to a sheet within an excel file as a number, or can we refer to it as the sheet name instead?

What does the guess_max argument do?

What happens if columns in the Excel worksheet are of different length?

Use the starwars dataset that is loaded with the tidyverse. Accomplish the following in one long string of pipes.

• Keep only observations with weight and height recorded.
• Create a variable called bmi that calculates the character’s BMI.
• Summarize the BMI variable, grouping observations by homeworld.
• Print this summary in decreasing order of average BMI.

Read in the following data into R. This data is from the American Community Survey and references the population of three cities in Virginia between 2009 and 2012. cities <- data.frame(name = rep(c("richmond", "norfolk", "charlottesville")), pop2009 = c(1202494,236071,191515), pop2010 = c(1235565,242143,197279), pop2011 = c(1248271,241943,199675), pop2012 = c(1260202,243056,210909)) In one long string of pipes, convert the data from wide (2009 to 2012 population values) to long format, naming the new column of populations pop, group by city, create a summary variable that is the ratio of the largest population value to smallest population value for the city, and arrange by this ratio value in decreasing order.