Date mischief and data joins

Getting started

The research crew wants to determine if there is a relationship between isotope levels and temperature. We have temperature data for each of the islands which have been helpfully uploaded to GitHub.

• https://raw.githubusercontent.com/tidy-MN/R-camp-penguins/main/public/data/Biscoe_temperatures.csv
• https://raw.githubusercontent.com/tidy-MN/R-camp-penguins/main/public/data/Dream_temperatures.csv
• https://raw.githubusercontent.com/tidy-MN/R-camp-penguins/main/public/data/Torgersen_temperatures.csv

Let’s get all of this data into R so we can combine it with our penguin data. Hint: use read_csv.

biscoe <- read_csv("https://raw.githubusercontent.com/tidy-MN/R-camp-penguins/main/public/data/Biscoe_temperatures.csv")

dream <- read_csv("https://raw.githubusercontent.com/tidy-MN/R-camp-penguins/main/public/data/Dream_temperatures.csv")

torg <- read_csv("https://raw.githubusercontent.com/tidy-MN/R-camp-penguins/main/public/data/Torgersen_temperatures.csv")

Clean-up time

The island names are in the file name, but are not in the data itself. Let’s add the island names to use for joining later. Remember that R is picky about names matching, so it’s important to make sure the names are exactly correct including caps. The island names are Biscoe, Dream, and Torgersen. Copy/paste is your friend here.

biscoe <- biscoe %>%
  mutate(island = "Biscoe")

dream <- dream %>%
  mutate(island = "Dream")

torg <- torg %>%
  mutate(island = "Torgersen")

Do you notice anything about the dates? They are all in different formats! Luckily we have lubridate to come to the rescue. Let’s convert those dates.

biscoe <- biscoe %>%
  mutate(date = mdy(date))

dream <- dream %>%
  mutate(date = dmy(date))

torg <- torg %>%
  mutate(island = ymd(date))

Putting it all together

To join the temperature data to our penguin data easily, we want to combine all 3 data frames into one data frame. Keeping in mind tidy data, what is the best way to do this?

temps <- rbind(biscoe, dream, torg)

Now that we have a tidy penguin data frame and a tidy temperature data frame, it’s time to combine them into one mega data frame. Both data frames have an island name and a date. What operation do we want to use? Which type is most appropriate here? The resulting data frame should have the same number of rows as the penguin data frame.

#inner join works the same in this instance
penguins_temps <- left_join(penguins_raw, temps,
                            by = c("Island" = "island",
                                   "Date Egg" = "date")
                            )