EVOLUTION-MANAGER

Edit File: rvest.R

## ---- echo=FALSE--------------------------------------------------------------
knitr::opts_chunk$set(comment = "#>", collapse = TRUE)

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library(rvest)

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html <- read_html("http://rvest.tidyverse.org/")
class(html)

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html <- minimal_html("
 This is a paragraph
 <ul>
 <li>This is a bulleted list</li>
 </ul>
")
html

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html <- minimal_html("
 <h1>This is a heading</h1>
 This is a paragraph
 This is an important paragraph
")

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html %>% html_element("h1")
html %>% html_elements("p")
html %>% html_elements(".important")
html %>% html_elements("#first")

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html <- minimal_html("
 <ol>
 <li>apple &amp; pear</li>
 <li>banana</li>
 <li>pineapple</li>
 </ol>
")
html %>% 
 html_elements("li") %>% 
 html_text2()

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html %>% 
  html_elements("li") %>% 
  html_text()

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html <- minimal_html("<body>
 
 This is
 a
 paragraph.This is another paragraph.
 
 It has two sentences.
")

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html %>% 
  html_element("body") %>% 
  html_text2() %>% 
  cat()

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html %>% 
  html_element("body") %>% 
  html_text() %>% 
  cat()

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html <- minimal_html("
 <a href='https://en.wikipedia.org/wiki/Cat'>cats</a>
 <img src='https://cataas.com/cat' width='100' height='200'>
")

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html %>% 
  html_elements("a") %>% 
  html_attr("href")

html %>% 
  html_elements("img") %>% 
  html_attr("src")

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html %>% 
  html_elements("img") %>% 
  html_attr("width")

html %>% 
  html_elements("img") %>% 
  html_attr("width") %>% 
  as.integer()

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html <- minimal_html("
 <table>
 <tr>
 <th>x</th>
 <th>y</th>
 </tr>
 <tr>
 <td>1.5</td>
 <td>2.7</td>
 </tr>
 <tr>
 <td>4.9</td>
 <td>1.3</td>
 </tr>
 <tr>
 <td>7.2</td>
 <td>8.1</td>
 </tr>
 </table>
 ")

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html %>% 
  html_node("table") %>% 
  html_table()

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html <- minimal_html("
 <ul>
 <li>C-3PO is a droid that weighs 167 kg</li>
 <li>R2-D2 is a droid that weighs 96 kg</li>
 <li>Yoda weighs 66 kg</li>
 <li>R4-P17 is a droid</li>
 </ul>
 ")

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html %>% html_elements("b") %>% html_text2()
html %>% html_elements("i") %>% html_text2()
html %>% html_elements(".weight") %>% html_text2()

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characters <- html %>% html_elements("li")

characters %>% html_element("b") %>% html_text2()
characters %>% html_element("i") %>% html_text2()
characters %>% html_element(".weight") %>% html_text2()

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data.frame(
  name = characters %>% html_element("b") %>% html_text2(),
  species = characters %>% html_element("i") %>% html_text2(),
  weight = characters %>% html_element(".weight") %>% html_text2()
)