Question

我试图抓取页面https://en.wikipedia.org/wiki/UEFA_Euro_2012_squads，并且可以使用rvest取消文本数据

library(plyr)
library(XML)
library(rvest)
library(dplyr)
library(magrittr)
library(data.table)

for(i in 1:16)
{
float <- paste("squad", i, sep ="")
print(float)
html = read_html("https://en.wikipedia.org/wiki/UEFA_Euro_2012_squads")
assign(float, html_table(html_nodes(html, "table")[[i]]))
}

但是也希望在俱乐部的每张桌子上添加一个额外的列。例如对于小队1（页面上的波兰小队，截断以显示前5名球员）

     0#0 Pos.              Player                    Date of birth (age) Caps Goals                Club
1   1  1GK  Wojciech SzczÄ™sny    (1990-04-18)18 April 1990 (aged 22)   11     0             Arsenal
2   2  2DF  Sebastian Boenisch  (1987-02-01)1 February 1987 (aged 25)    9     0       Werder Bremen
3   3  2DF Grzegorz Wojtkowiak  (1984-01-26)26 January 1984 (aged 28)   19     0        Lech PoznaÅ„
4   4  2DF    Marcin KamiÅ„ski  (1992-01-15)15 January 1992 (aged 20)    3     0        Lech PoznaÅ„
5   5  3MF       Dariusz Dudka  (1983-12-09)9 December 1983 (aged 28)   65     2             Auxerre
6   6  3MF     Adam Matuszczyk (1989-02-14)14 February 1989 (aged 23)   20     1 Fortuna DÃ¼sseldorf

我希望在“clubURL”的“俱乐部”之后的专栏中显示该俱乐部的维基百科网址。例如，第一个球员为阿森纳效力，所以要把桌面上的链接拿给阿森纳并创造：

0#0 Pos.             Player                 Date of birth (age) Caps Goals    Club
1   1  1GK Wojciech SzczÄ™sny (1990-04-18)18 April 1990 (aged 22)   11     0 Arsenal
                                     clubURL
1 https://en.wikipedia.org/wiki/Arsenal_F.C.

依此类推。我发现rvest table scraping including links但是无法让这个例子起作用，也不能让我想做的事情。对不起，如果在其他地方被问过，

感谢，

Answer 1

我使用页面上的第一个表格做了一个例子。您可以根据需要进行扩展。

首先，抓住第一个表并使用html_table保存。然后我创建了一个辅助函数，在给定链接文本的情况下从表中提取链接。然后我使用sapply填充数据框中的新列。

library("rvest")
url <- "https://en.wikipedia.org/wiki/UEFA_Euro_2012_squads"
mytable <- read_html(url) %>% html_nodes("table") %>% .[[1]] 
df <- mytable %>% html_table()

get_link <- function(html_table, team){
  html_table %>% 
    html_nodes(xpath=paste0("//a[text()='", team, "']")) %>% 
    .[[1]] %>% 
    html_attr("href")
}

df$club_link <- sapply(df$Club, function(x)get_link(mytable, x))
> head(df)
  0#0 Pos.              Player
1   1  1GK  Wojciech SzczÄ™sny
2   2  2DF  Sebastian Boenisch
3   3  2DF Grzegorz Wojtkowiak
4   4  2DF    Marcin KamiÅ„ski
5   5  3MF       Dariusz Dudka
6   6  3MF     Adam Matuszczyk
                     Date of birth (age) Caps Goals
1    (1990-04-18)18 April 1990 (aged 22)   11     0
2  (1987-02-01)1 February 1987 (aged 25)    9     0
3  (1984-01-26)26 January 1984 (aged 28)   19     0
4  (1992-01-15)15 January 1992 (aged 20)    3     0
5  (1983-12-09)9 December 1983 (aged 28)   65     2
6 (1989-02-14)14 February 1989 (aged 23)   20     1
                 Club                     club_link
1             Arsenal            /wiki/Arsenal_F.C.
2       Werder Bremen        /wiki/SV_Werder_Bremen
3        Lech PoznaÅ„        /wiki/Lech_Pozna%C5%84
4        Lech PoznaÅ„        /wiki/Lech_Pozna%C5%84
5             Auxerre              /wiki/AJ_Auxerre
6 Fortuna DÃ¼sseldorf /wiki/Fortuna_D%C3%BCsseldorf

从维基百科表中抓取网址

1 个答案: