The Complete Sherlock Holmes

library(tidyverse) # ggplot, lubridate, dplyr, stringr, readr...
library(praise)
library(tidytext)
library(rvest)

The Data

This week we’re exploring the complete line-by-line text of the Sherlock Holmes stories and novels, made available through the {sherlock} R package by Emil Hvitfeldt. The dataset includes the full collection of Holmes texts, organized by book and line number, and is ideal for stylometry, sentiment analysis, and literary exploration.

“The name is Sherlock Holmes and the address is 221B Baker Street.” Holmes is a consulting detective known for his keen observation, logical reasoning, and use of forensic science to solve complex cases. Created by Sir Arthur Conan Doyle, Holmes has become one of the most famous fictional detectives in literature.

• Are there patterns in how Watson narrates versus how Holmes speaks?
• How does sentence length vary between stories?
• Can we detect shifts in tone when Watson is the narrator versus when Holmes speaks directly?
• Does sentiment shift as the mystery unfolds?

Thank you to Darakhshan Nehal for curating this week’s dataset.

holmes <- readr::read_csv('https://raw.githubusercontent.com/rfordatascience/tidytuesday/main/data/2025/2025-11-18/holmes.csv') |> 
  mutate(book = tolower(book)) |> 
  mutate(book = str_squish(book))

First we find the dates of each of the Sherlock Holmes texts from Wikipedia. Using regular expressions, we are able to pull out the dates.

holmes_wiki <- read_html("https://en.wikipedia.org/wiki/Canon_of_Sherlock_Holmes") |> 
  html_elements("p+ ol li , p+ ol a") |> 
  html_text() |> 
  as_tibble() |> 
  filter(!is.na(str_extract(value, "\\d{4}"))) |> 
  mutate(date = str_extract(value, "\\d{4}")) |> 
  mutate(title = str_extract(value, '^"?([^"(]+)"?')) |> 
  mutate(title = str_replace_all(title, '"', '')) |> 
  mutate(title = tolower(title)) |> 
  mutate(title = str_squish(title))


holmes <- holmes |> 
  left_join(holmes_wiki, by = c("book" = "title"))

Next we use the AFINN sentiment analysis to identify the sentiment (or sentiments) associated with each line in the text.

afinn_sentiments <- tidytext::get_sentiments("afinn") 
nrc_sentiments <- tidytext::get_sentiments("nrc") |> 
  filter(sentiment != "positive", sentiment != "negative")

sent_data <- holmes |> 
  tidytext::unnest_tokens(words, text) |> 
  anti_join(stop_words, by = c("words" = "word")) |> 
  left_join(nrc_sentiments, by = c("words" = "word"), relationship = "many-to-many") |> 
  group_by(date, sentiment) |> 
  summarize(n = n()) |> 
  filter(!is.na(sentiment)) |> 
  mutate(prop = n / sum(n)) |> 
  mutate(date = as.numeric(date))

sent_data |> 
  ggplot(aes(x = date, y = prop)) + 
  geom_line(aes(color = sentiment)) + 
  geom_point(aes(color = sentiment)) + 
  scale_color_brewer(palette = "Dark2") + 
  geom_vline(xintercept = c(1893, 1903)) + 
  labs(title = "proportion of each sentiment",
       y = "", x = "") + 
  geom_text(label = "Holmes dies", x = 1894, y = 0.22) +
  geom_text(label = "Holmes resurrected", x = 1904, y = 0.22)

Sentiment proportion over all lines from books published in a given year.

It was too hard to put all the titles on the graph, so we list them here, by date.

holmes |> 
  distinct(date, book) |> 
  filter(!is.na(date)) |> 
  arrange(date) |> 
  gt::gt()

date	book
1887	a study in scarlet
1890	the sign of the four
1891	a scandal in bohemia
1891	the red-headed league
1891	a case of identity
1891	the boscombe valley mystery
1891	the five orange pips
1891	the man with the twisted lip
1892	the adventure of the blue carbuncle
1892	the adventure of the speckled band
1892	the adventure of the engineer's thumb
1892	the adventure of the noble bachelor
1892	the adventure of the beryl coronet
1892	the adventure of the copper beeches
1893	the adventure of the cardboard box
1901	the hound of the baskervilles
1903	the adventure of the empty house
1903	the adventure of the norwood builder
1903	the adventure of the dancing men
1904	the adventure of the solitary cyclist
1904	the adventure of the priory school
1904	the adventure of black peter
1904	the adventure of charles augustus milverton
1904	the adventure of the six napoleons
1904	the adventure of the three students
1904	the adventure of the golden pince-nez
1904	the adventure of the missing three-quarter
1904	the adventure of the abbey grange
1904	the adventure of the second stain
1908	the adventure of wisteria lodge
1908	the adventure of the bruce-partington plans
1910	the adventure of the devil's foot
1911	the adventure of the red circle
1911	the disappearance of lady frances carfax
1913	the adventure of the dying detective
1914	the valley of fear
1917	his last bow

praise()

[1] "You are astonishing!"