如何使用 R 中的 rvest 通过以下方式从 Wikipedia 获取“类别”？

Posted 2023-03-24

【中文标题】如何使用 R 中的 rvest 通过以下方式从 Wikipedia 获取“类别”？

【英文标题】：How can I obtain "Categories" from Wikipedia in the following way using rvest in R?

【发布时间】：2018-02-15 16:40:20

【问题描述】：

我希望使用 R 中的 rvest 获取类别（***页面的最底部）。我使用 SelectorGadget 来识别用于类别提取的 html 节点。我使用的代码如下

thepage <- read_html("https://en.wikipedia.org/wiki/San_Diego")
Categories <- thepage %>% 
            html_nodes("#mw-normal-catlinks") %>%
            html_text()
Categories

得到的结果如下：

"Categories: San Diego1769 establishments in California1850 establishments in CaliforniaCities in San Diego County, CaliforniaCounty seats in CaliforniaIncorporated cities and towns in CaliforniaPopulated coastal places in CaliforniaPopulated places established in 1769San Antonio-San Diego Mail LineSan Diego County, CaliforniaSan Diego metropolitan areaSpanish mission settlements in North AmericaSpecial economic zones of the United StatesStagecoach stops in the United States"

如您所见，类别之间没有分隔符。第一类是“圣地亚哥”，第二类是“加利福尼亚州的 1769 家机构”。如何在列表中获取这些类别或以某种方式分隔？

【参考方案1】：

每个类别都是一个列表项，所以需要进入列表：

thepage %>% 
  html_nodes(".mw-normal-catlinks ul li") %>% 
  html_text()

 [1] "San Diego"                                    "1769 establishments in California"           
 [3] "1850 establishments in California"            "Cities in San Diego County, California"      
 [5] "County seats in California"                   "Incorporated cities and towns in California" 
 [7] "Populated coastal places in California"       "Populated places established in 1769"        
 [9] "San Antonio-San Diego Mail Line"              "San Diego County, California"                
[11] "San Diego metropolitan area"                  "Spanish mission settlements in North America"
[13] "Special economic zones of the United States"  "Stagecoach stops in the United States"