Customizing tables is fun (seriously) with gt

It really just works…

Make a table of the first 5 observations in the ‘rock’ dataset.

rock %>% # Get 'rock' data
  head(5) %>% # First 5 lines only
  gt() # Make a table, it just works. 

The first try at customization

Biological oxygen demand table (BOD)

Use the built-in dataset BOD to create a simple customized table. The BOD dataset (see ?BOD for documentation) has two columns: Time and demand (both numeric).

BOD %>% # Get the data...
gt() %>% # use 'gt' to make an awesome table...
  tab_header( 
    title = "BOD Table Woooooo!", # ...with this title
    subtitle = "Hooray gt!") %>% # and this subtitle
  fmt_number( # A column (numeric data)
    columns = vars(Time), # What column variable? BOD$Time
    decimals = 2 # With two decimal places
    ) %>% 
  fmt_number( # Another column (also numeric data)
    columns = vars(demand), # What column variable? BOD$demand
    decimals = 1 # I want this column to have one decimal place
  ) %>% 
  cols_label(Time = "Time (hours)", demand = "Demand (mg/L)") # Update labels

The one where I added colors and footnotes

ToothGrowth (VitC effect on tooth growth in guinea pigs)

See ?ToothGrowth for dataset documentation. The ToothGrowth dataset has three variables: len (tooth length), supp (supplement ID), dose (dosage). I use group_by() + summarize() here to find mean tooth length grouped by supplement and dosage first, then create a table of the means.

# Some wrangling (grouped means by supplement + dosage):

tooth_length <- ToothGrowth %>% 
  group_by(supp, dose) %>% 
  summarize(
    mean_len = mean(len)
  ) %>% 
  as_tibble() 

# A gt table: 
tooth_length %>% # Take tooth_length
  gt() %>% # Make a gt table with it
  tab_header(
    title = "A title just like that", # Add a title
    subtitle = "(with something below it!)" # And a subtitle
  ) %>%
  fmt_passthrough( # Not sure about this but it works...
    columns = vars(supp) # First column: supp (character)
  ) %>% 
  fmt_number(
    columns = vars(mean_len), # Second column: mean_len (numeric)
    decimals = 2 # With 4 decimal places
  ) %>% 
  fmt_number(
    columns = vars(dose), # Third column: dose (numeric)
    decimals = 2 # With 2 decimal places
  ) %>% 
  data_color( # Update cell colors...
    columns = vars(supp), # ...for supp column!
    colors = scales::col_factor( # <- bc it's a factor
      palette = c(
        "green","cyan"), # Two factor levels, two colors
      domain = c("OJ","VC")# Levels
  )
  ) %>% 
  data_color( # Update cell colors...
    columns = vars(dose), # ...for dose column 
    colors = scales::col_numeric( # <- bc it's numeric
      palette = c(
        "yellow","orange"), # A color scheme (gradient)
      domain = c(0.5,2) # Column scale endpoints
  )
  ) %>% 
  data_color( # Update cell colors...
    columns = vars(mean_len), # ...for mean_len column
    colors = scales::col_numeric(
      palette = c(
        "red", "purple"), # Overboard colors! 
      domain = c(7,27) # Column scale endpoints
  )
  ) %>% 
  cols_label(supp = "Supplement", dose = "Dosage (mg/d)", mean_len = "Mean Tooth Length") %>% # Make the column headers
  tab_footnote(
    footnote = "Baby footnote test", # This is the footnote text
    locations = cells_column_labels(
      columns = vars(supp) # Associated with column 'supp'
      )
    ) %>% 
    tab_footnote(
    footnote = "A second footnote", # Another line of footnote text
    locations = cells_column_labels( 
      columns = vars(dose) # Associated with column 'dose'
      )
    )

Updating NAs, hiding columns

Using first 10 observations in the ‘airquality’ dataset. Existing variables: Ozone, Solar.R, Wind, Temp, Month, Day

airquality %>% # Take the 'airquality' dataset...
  head(10) %>% # Then just grab the first 10 observations...
  gt() %>% # Then make a gt table
  tab_header(
    title = "Air Quality dataset", # Add a title
    subtitle = "...also with a subtitle" # And a subtitle
  ) %>%
  fmt_missing( # Then reassign the 'NA' values to something new
    columns = vars(Ozone), # For variable 'Ozone', make "NA"s
    missing_text = "Teddy" # ...to "Teddy" instead
  ) %>% 
  fmt_missing( # Reassign NAs for another column
    columns = vars(Solar.R), # For variable 'Solar.R', make "NA"s
    missing_text = "Dog" # ...to "Dog" instead
  ) %>% 
  cols_hide( # Then hide the 'Wind' and 'Month' variables
    columns = vars(Wind, Month)
  )

Scientific notation (…and more colors, can’t help it…)

I’ll just make some data here (tibble ‘fake’):

fake <- tribble( # Create a tibble...
  ~Species, ~Height, ~Mass, # These will be the column names (variables)
  "Blarg", 20500, 1980, # Row 1
  "Gorple", 17000, 775, # Row 2
  "Roglob", 11820, 20, # Row 3
  "Fwerpy", 8005, 352 # Row 4
) %>% 
  arrange(-Mass) # Arrange high-to-low by values in Mass column

Then make a little table of ‘fake’ with values in scientific notation:

fake %>% 
  gt() %>% 
  tab_header(
    title = "Fake species data", # Add a title
    subtitle = "another useful subtitle" # And a subtitle
  ) %>%
  fmt_scientific( # Reformat to scientific notation...
    columns = vars(Height), # The values for the 'Height' variable
    decimals = 3 # Keeping 3 decimal places
  ) %>% 
  fmt_scientific( # Reformat to scientific notation...
    columns = vars(Mass), # The values for the 'Mass' variable
    decimals = 1 # Keeping 1 decimal place
  ) %>% 
  data_color( # Update cell colors...
    columns = vars(Mass), # ...for Mass column 
    colors = scales::col_numeric( # <- bc it's numeric
      palette = c(
        "yellow", "red", "purple"), # A color scheme (gradient)
      domain = c(1e1, 2e3) # Column scale endpoints
  )
  )

Date formatting + column spanning labels

First, I’ll make a little tibble with dates:

date_trial <- tribble( # Create a tibble...
  ~Date, ~Temp, ~Rain, ~Flavor, # These will be the variables (column names)
  "1980-01-04", 75, 0.4, "Grape", # Row 1 
  "1975-05-28", 80, 0.2, "Strawberry", # Row 2
  "1993-09-02", 94, 0.1, "Chocolate" # Row 3
)

Then into a nice table:

date_trial %>% 
  gt() %>% 
  fmt_date(
    columns = vars(Date),
    date_style = 5 # Try different numbers here to reformat! So cool!
  ) %>% 
  tab_spanner(
    label = "Weather",
    columns = vars(Temp, Rain)
  )

Give gt a whirl! For me, the trade-off of writing more lines- but ones that I can easily understand and control when customizing tables - is well worth it, and actually pretty fun.