rvest::html_nodes returns 部分列表（只有几项）

Question

使用 rvest 包，我试图从电影肯尼迪 (https://www.imdb.com/title/tt0102138/fullcredits?ref_=tt_ql_1) 的 IMDB 页面中抓取 actors/actresses 的名字。

SelectorGadget 说我想找的地方是每个人的 "td:nth-child(2)"。

这是我正在使用的代码。

        library(rvest)
        library(stringr)

        startFilm <- "tt0102138" #JFK
        personsNames <- c()
        pagePath <- paste("https://www.imdb.com/title/", startFilm, "/?ref_=nv_sr_1?ref_=nv_sr_1", sep = "")
        moviePage <- read_html(pagePath)
        personNodes <- html_nodes(moviePage, "td:nth-child(2)")
        personText <- html_text(personNodes)
        for (i in 1:length(personText)){
                actor <- (unlist(str_split(personText[i], "\n")))[2]
                personsNames[i] <- substring(actor, 2, nchar(actor))
        }
        personsNames

根据 https://www.imdb.com/title/tt0102138/fullcredits?ref_=tt_ql_1 的网站，此列表应该相当长。

然而，当我运行代码时，我只得到 15 个名字。

[1] "Sally Kirkland"  "Anthony Ramirez" "Ray LePere"      "Steve Reed"      "Jodie Farber"    "Columbia Dubose"
[7] "Randy Means"     "Kevin Costner"   "Jay O. Sanders"  "E.J. Morris"     "Cheryl Penland"  "Jim Gough"
[13] "Perry R. Russo"  "Mike Longman"    "Edward Asner"

为什么名单 t运行被分类了？

我应该如何调整我的代码以获得电影中 actors/actresses 的完整列表？

Answer 1

从 html_nodes

获取名称后，您需要进行一些数据清理

url <- "https://www.imdb.com/title/tt0102138/fullcredits?ref_=tt_ql_1"
library(rvest)

url %>%
   read_html() %>%
   html_nodes("td:nth-child(2)") %>%
   html_text() %>%
   grep("...", ., invert = TRUE, value = TRUE, fixed = TRUE) %>%
   trimws %>%
  .[. != ""]

#  [1] "Sally Kirkland"             "Anthony Ramirez"            "Ray LePere"                
#  [4] "Steve Reed"                 "Jodie Farber"               "Columbia Dubose"      
#  [7] "Randy Means"                "Kevin Costner"              "Jay O. Sanders"   
# [10] "E.J. Morris"                "Cheryl Penland"             "Jim Gough"      
# [13] "Perry R. Russo"             "Mike Longman"               "Edward Asner"    
# [16] "Jack Lemmon"                "Vincent D'Onofrio"          "Gary Oldman"
#....

Answer 2

这是我所做的。如果你只是需要actors/actresses，你可以运行下面的代码。我确定了具体位置。这样就可以精确的得到actors/actresses的名字；无需字符串操作。

library(rvest)
library(stringi)

read_html("https://www.imdb.com/title/tt0102138/fullcredits?ref_=tt_ql_1") %>% 
html_nodes("td.primary_photo") %>% 
html_nodes("img") %>% 
html_attr("alt")

#  [1] "Sally Kirkland"             "Anthony Ramirez"            "Ray LePere"                 "Steve Reed"                
#  [5] "Jodie Farber"               "Columbia Dubose"            "Randy Means"                "Kevin Costner"  
#[249] "Mark Edward Walters"        "Earl Warren"                "John B. Wells"              "Jim White"                 
#[253] "Phillip L. Willis"          "Rosemary Willis"            "Louis Steven Witt"          "Angus G. Wynne III"

作为奖励，如果你想创建一个包含名字和角色名字的数据框，你可以尝试以下方法。

mydf <- tibble(actors = read_html("https://www.imdb.com/title/tt0102138/fullcredits?ref_=tt_ql_1") %>% 
                 html_nodes("td.primary_photo") %>% 
                 html_nodes("img") %>% 
                 html_attr("alt"),
               characters = read_html("https://www.imdb.com/title/tt0102138/fullcredits?ref_=tt_ql_1") %>% 
                 html_nodes(".character") %>% 
                 html_text() %>% 
                 stri_replace_all_regex(pattern = "\n|\s{2,}", replacement = ""))

#  actors          characters                             
#   <chr>           <chr>                                  
# 1 Sally Kirkland  Rose Cheramie                          
# 2 Anthony Ramirez Epileptic                              
# 3 Ray LePere      Zapruder                               
# 4 Steve Reed      John F. Kennedy - Double               
# 5 Jodie Farber    Jackie Kennedy - Double(as Jodi Farber)
# 6 Columbia Dubose Nellie Connally - Double               
# 7 Randy Means     Gov. Connally - Double                 
# 8 Kevin Costner   Jim Garrison                           
# 9 Jay O. Sanders  Lou Ivon                               
#10 E.J. Morris     Plaza Witness #1

rvest::html_nodes returns 部分列表（只有几项）

rvest::html_nodes returns a partial list (only a few items)

r

imdb

web-scraping

rvest