Plot Labels

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

library(tidyverse)

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

penguins <- read_csv("penguins.csv")
			
# Plot Labels -------------------------------------------------------------

# To start, let's make a new data frame

penguin_bill_length_by_island_and_sex <- penguins |> 
  drop_na(sex) |> 
  group_by(island, sex) |> 
  summarize(mean_bill_length = mean(bill_length_mm))

# Now let's plot this data frame using a bar chart.

ggplot(data = penguin_bill_length_by_island_and_sex,
       mapping = aes(x = island,
                     y = mean_bill_length,
                     fill = sex)) +
  geom_col()

# The bars are stacked by default. 
# To put them side by side, we use the 
# position = "dodge" argument within geom_col().

ggplot(data = penguin_bill_length_by_island_and_sex,
       mapping = aes(x = island,
                     y = mean_bill_length,
                     fill = sex)) +
  geom_col(position = "dodge")

# To add labels to our plot, we use labs().

# We can add a title to the plot with the title argument.

ggplot(data = penguin_bill_length_by_island_and_sex,
       mapping = aes(x = island,
                     y = mean_bill_length,
                     fill = sex)) +
  geom_col(position = "dodge") +
  labs(title = "Males have longer bills than females")

# We can also add a subtitle and caption

ggplot(data = penguin_bill_length_by_island_and_sex,
       mapping = aes(x = island,
                     y = mean_bill_length,
                     fill = sex)) +
  geom_col(position = "dodge") +
  labs(title = "Males have longer bills than females",
       subtitle = "But they're all good penguins",
       caption = "Data from the palmerpenguins R package")

# We can change the x and y axis labels using the x and y arguments.

ggplot(data = penguin_bill_length_by_island_and_sex,
       mapping = aes(x = island,
                     y = mean_bill_length,
                     fill = sex)) +
  geom_col(position = "dodge") +
  labs(title = "Males have longer bills than females",
       subtitle = "But they're all good penguins",
       caption = "Data from the palmerpenguins R package",
       x = "Island",
       y = "Mean Bill Length in Millimeters")

# To change the legend title, 
# we use the name of the aesthetic that is being shown.

ggplot(data = penguin_bill_length_by_island_and_sex,
       mapping = aes(x = island,
                     y = mean_bill_length,
                     fill = sex)) +
  geom_col(position = "dodge") +
  labs(title = "Males have longer bills than females",
       subtitle = "But they're all good penguins",
       caption = "Data from the palmerpenguins R package",
       x = "Island",
       y = "Mean Bill Length in Millimeters",
       fill = "Sex")

# You can remove plot labels using NULL

ggplot(data = penguin_bill_length_by_island_and_sex,
       mapping = aes(x = island,
                     y = mean_bill_length,
                     fill = sex)) +
  geom_col(position = "dodge") +
  labs(title = "Males have longer bills than females",
       subtitle = "But they're all good penguins",
       caption = "Data from the palmerpenguins R package",
       x = NULL,
       y = "Mean Bill Length in Millimeters",
       fill = NULL)