问题描述
我正在使用 R rvest 库来读取包含表格的 html 页面.不幸的是，这些表格的列数不一致.
I am using the R rvest library to read an html page containing tables.Unfortunately the tables have inconsistent number of columns.
这是我阅读的表格示例:
Here is an example of the table I read:
<table>
<tr class="alt">
<td>1</td>
<td>2</td>
<td class="hidden">3</td>
</tr>
<tr class="tr0 close notule">
<td colspan="9">4</td>
</tr>
</table>
和我在 R 中读取表格的代码:
and my code to read the table in R:
require(rvest)
url = "table.html"
x <- read_html(url)
(x %>% html_nodes("table")) %>% html_table(fill=T)
# [[1]]
# X1 X2 X3 X4 X5 X6 X7 X8 X9
# 1 1 2 3 NA NA NA NA NA NA
# 2 4 4 4 4 4 4 4 4 4
我想避免考虑隐藏类的 td 和类 'tr0 close notule' 的 tr，所以我只能得到如下表:
I would like to avoid considering the td of class hidden and the tr of class 'tr0 close notule', so that I ony get a table as follows:
X1 X2
1 2
有没有办法用 rvest 做到这一点?
Is there a way to do that with rvest?
推荐答案
通过使用 xml_remove()，你可以从字面上删除那些节点
By using xml_remove(), you can literally remove those nodes
text <- '<table>
<tr class="alt">
<td>1</td>
<td>2</td>
<td class="hidden">3</td>
</tr>
<tr class="tr0 close notule">
<td colspan="9">4</td>
</tr>
</table>'
html_tree <- read_html(text)
#select nodes you want to remove
hidden_nodes <- html_tree %>%
html_nodes(".hidden")
close_nodes <- html_tree %>%
html_nodes(".tr0.close.notule")
#remove those nodes
xml_remove(hidden_nodes)
xml_remove(close_nodes)
html_tree %>%
html_table()
我检查了 css，发现这些节点的 css 类似于:tr0 close notule,tr1 close notule,...,tr{n} close notule，所以你需要更一般地选择所有这些节点
I examined the css and found that the css for those nodes are like: tr0 close notule,tr1 close notule,...,tr{n} close notule, so you need to be more general to select all those nodes
library(purrr)
library(rvest)
my_session <- html_session("https://www.zone-turf.fr/cheval/greaty-lion-592958/")
#select all table nodes
tables <- my_session %>%
html_nodes(".inner2 > table")
# remove nodes with class of "close and notule"
close_nodes <- tables %>%
html_nodes(".close.notule")
xml_remove(close_nodes)
#use map to create all tables and store them in a list.
map(tables,~ .x %>% html_table())
调整要删除的节点的 css 选择器后，它应该可以工作:
After adjusting the css selector for nodes to remove, it should work:
#sample output --------------
[[8]]
RangRg Cheval S/A CordeC PoidsPds Jockey Cote Ecart
1 1 Latita F2 3 57,5 T. Piccone 6.3 1'56"05 NA
2 2 Youmzain Star M2 6 59 F. Veron 4.7 3/4 NA
3 3 Pharrell M2 1 59 J.B. Eyquem 1.9 1 NA
4 4 King Bubble M2 4 58 N. Perret 15.5 1 NA
5 5 Dark Side M2 5 57 A. Hamelin 12.4 8 NA
6 6 Greaty Lion F2 2 57,5 F. Blondel 6.8 15 NA
[[9]]
RangRg Cheval S/A CordeC PoidsPds Jockey Cote Ecart
1 1 Marianafoot M2 4 59 N. Perret 2.1 1'40"25 lire
2 2 Ballet de la Reine F2 2 54 H. Journiac 3.4 1 1/2
3 3 Greaty Lion F2 5 57,5 F. Blondel 7.0 2
4 4 Beau Massagot M2 6 54 E. Cieslik 9.7 5
5 5 London Look M2 3 58 T. Piccone 8.8 5,5
6 6 Spirit Louve F2 1 53 L. Grosso 18.8 Tête
[[10]]
RangRg Cheval S/A CordeC PoidsPds Jockey Cote Ecart
1 1 Greaty Lion F2 12 58 F. Blondel 3.6 1'43"84 NA
2 2 Maeghan F2 11 58 G. Millet 5.1 1 NA
3 3 Neige Eternelle F2 8 58 A. Roussel 3.8 1 3/4 NA
4 4 Fair la Joie F2 9 58 G. Congiu 11.6 1/4 NA
5 5 Nicky Green F2 7 58 R. Thomas 6.4 1/4 NA
6 6 Coral Slipper F2 5 58 A. Fouassier 28.4 1 1/4 NA
7 7 Gaia de Cerisy F2 13 58 D. Breux 32.5 1 NA
8 8 Luna Riska F2 1 58 N. Larenaudie 58.3 Encolure NA
9 9 Belle Vendome F2 2 56 A. Teissieux 49.9 2 1/2 NA
10 0 Rebel Dream F2 3 58 S. Leger 56.6 NA
11 0 Facinateur F2 4 56 M. Berto 21.2 NA
12 0 Giovanna F2 10 56 F. Garnier 27.8 NA
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