# The easiest way to get rvest is to install the whole tidyverse:
install.packages("tidyverse")
# Alternatively, install just rvest:
install.packages("rvest")

library(rvest)
# Start by reading a HTML page with read_html():
starwars <- read_html("https://rvest.tidyverse.org/articles/starwars.html")
# Then find elements that match a css selector or XPath expression
# using html_elements(). In this example, each <section> corresponds
# to a different film
films <- starwars %>% html_elements("section")
films
#> {xml_nodeset (7)}
#> [1] <section><h2 data-id="1">\nThe Phantom Menace\n</h2>\n<p>\nReleased: 1999 ...
#> [2] <section><h2 data-id="2">\nAttack of the Clones\n</h2>\n<p>\nReleased: 20 ...
#> [3] <section><h2 data-id="3">\nRevenge of the Sith\n</h2>\n<p>\nReleased: 200 ...
#> [4] <section><h2 data-id="4">\nA New Hope\n</h2>\n<p>\nReleased: 1977-05-25\n ...
#> [5] <section><h2 data-id="5">\nThe Empire Strikes Back\n</h2>\n<p>\nReleased: ...
#> [6] <section><h2 data-id="6">\nReturn of the Jedi\n</h2>\n<p>\nReleased: 1983 ...
#> [7] <section><h2 data-id="7">\nThe Force Awakens\n</h2>\n<p>\nReleased: 2015- ...
# Then use html_element() to extract one element per film. Here
# we the title is given by the text inside <h2>
title <- films %>% 
  html_element("h2") %>% 
  html_text2()
title
#> [1] "The Phantom Menace"      "Attack of the Clones"   
#> [3] "Revenge of the Sith"     "A New Hope"             
#> [5] "The Empire Strikes Back" "Return of the Jedi"     
#> [7] "The Force Awakens"
# Or use html_attr() to get data out of attributes. html_attr() always
# returns a string so we convert it to an integer using a readr function
episode <- films %>% 
  html_element("h2") %>% 
  html_attr("data-id") %>% 
  readr::parse_integer()
episode
#> [1] 1 2 3 4 5 6 7

html <- read_html("https://en.wikipedia.org/w/index.php?title=The_Lego_Movie&oldid=998422565")
html %>% 
  html_element(".tracklist") %>% 
  html_table()
#> # A tibble: 29 × 4
#>    No.   Title                       `Performer(s)`                       Length
#>    <chr> <chr>                       <chr>                                <chr> 
#>  1 1.    "\"Everything Is Awesome\"" "Tegan and Sara featuring The Lonel… 2:43  
#>  2 2.    "\"Prologue\""              ""                                   2:28  
#>  3 3.    "\"Emmett's Morning\""      ""                                   2:00  
#>  4 4.    "\"Emmett Falls in Love\""  ""                                   1:11  
#>  5 5.    "\"Escape\""                ""                                   3:26  
#>  6 6.    "\"Into the Old West\""     ""                                   1:00  
#>  7 7.    "\"Wyldstyle Explains\""    ""                                   1:21  
#>  8 8.    "\"Emmett's Mind\""         ""                                   2:17  
#>  9 9.    "\"The Transformation\""    ""                                   1:46  
#> 10 10.   "\"Saloons and Wagons\""    ""                                   3:38  
#> # ℹ 19 more rows