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R in 3 Months (Fall 2025)

select()

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View code shown in video 
# Load Packages -----------------------------------------------------------

library(tidyverse)

# Import Data -------------------------------------------------------------

penguins <- read_csv("penguins.csv")

# select() ----------------------------------------------------------------

penguins

# With select() we can select variables from the larger data frame.

penguins |> 
  select(bill_length_mm)

# We can also use select() for multiple variables:

penguins |>
  select(bill_length_mm, bill_depth_mm)

# select() has several helper functions for selecting variables.

# The contains() function finds any variable with certain text 
# in the variable name:

penguins |>
  select(contains("bill"))

# The starts_with() function allows us to select variables 
# that start with certain text:

penguins |> 
  select(starts_with("bill"))

# The ends_with() function allows us to select variables that end with certain text:

penguins |> 
  select(ends_with("mm"))

# We can select a range of columns using the var1:var2 pattern

penguins |> 
  select(species:bill_length_mm)

# We can drop variables using the -var format:

penguins |> 
  select(-bill_length_mm)

# We can drop a set of variables using the -(var1:var2) format:

penguins |> 
  select(-(bill_length_mm:flipper_length_mm))

Your Turn

Copy the code below into your R script file and complete the exercises. Please make sure you are using the CSV file that you downloaded from https://rfor.us/penguins. If you use the penguins_data.csv file from the Getting Started with R course or continue to use the penguins object you created in that course, you will run into problems!

# Load Packages -----------------------------------------------------------

# Load the tidyverse package

library(tidyverse)

# Import Data -------------------------------------------------------------

# Download data from https://rfor.us/penguins
# Copy the data into the RStudio project
# Create a new R script file and add code to import your data

penguins <- read_csv("penguins.csv")

# select() ----------------------------------------------------------------

# Use select() to keep only the sex variable

# YOUR CODE HERE

# Use select() to keep the island and sex variables

# YOUR CODE HERE

# Use one of the select() helper functions to keep all variables that have the letter s in their names

# YOUR CODE HERE

# Use one of the select() helper functions to keep all variables that start with the letter b

# YOUR CODE HERE

# Use select() to keep the variables from island to the end

# YOUR CODE HERE

# Use the dropping syntax with - to keep the same variables as above (island to the end)

# YOUR CODE HERE

# Drop all variables from bill_length_mm to body_mass_g
			
# YOUR CODE HERE

Learn More

To learn more about the select() function, check out Chapter 3 of R for Data Science.

Have any questions? Put them below and we will help you out!

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Course Content

128 Lessons