select()

This lesson is called select(), part of the Fundamentals of R course. This lesson is called select(), part of the Fundamentals of R course.

Transcript

Click on the transcript to go to that point in the video. Please note that transcripts are auto generated and may contain minor inaccuracies.

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

Solution

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

# Load the tidyverse package

library(tidyverse)

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

# Download data from https://rfor.us/penguins
# Copy the data into your Positron project where you downloaded the penguins data
# Overwrite your R code that you created previously with the code below

penguins <- read_csv("penguins.csv")

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

# Use select() to keep only the sex variable

penguins |> 
  select(sex)

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

penguins |> 
  select(island, sex)

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

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

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

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

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

penguins |> 
  select(island:year)

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

penguins |> 
  select(-species)

# Drop all variables from bill_length_mm to body_mass_g

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

Copy the code below into your R script file and complete the exercises.

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

# Load the tidyverse package

library(tidyverse)

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

# Download data from https://rfor.us/penguins
# Copy the data into your Positron project where you downloaded the penguins data
# Overwrite your R code that you created previously with the code below

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