rvest scraping, getting td for particular th (tranlsation from Python) - r

Question

Hi StackOverflow users,
Sorry for a silly question.
My question is a bit general, but here's an example:
Suppose I'm scraping Wikipedia infobox info on official webpages of US cities. So for a given list of Wikipedia URLs I need last row of infobox (the box on the right of the page) with the information on website.
In Python I will do it in this way. However, I cannot understand how to do it in R. So
r = requests.get("https://en.wikipedia.org/wiki/Los_Angeles")
if r:
text = r.text
soup = BeautifulSoup(text, 'lxml')
def get_website(soup):
for tr in soup.find("table",
class_="infobox")("tr"):
if tr.th and 'Website' in tr.th.text:
print(tr.td)
s = tr.td.p.string
return (s)

Answer 1

There's a better way in both Python & R via XPath.
library(rvest)
pg <- read_html("https://en.wikipedia.org/wiki/Los_Angeles")
html_node(pg, xpath=".//table[contains(#class,'infobox') and
tr[contains(., 'Website')]]/tr[last()]/td//a") -> last_row_link
html_text(last_row_link)
## [1] "Official website"
html_attr(last_row_link, "href")
## [1] "https://www.lacity.org/"
I made an assumption that you really wanted the href attribute of the link in the last <tr> but the las() expression in the XPath was the essential ingredient. The last td//a says (essentially) "once you find the <td> in the <tr> we just found, look where in the element subtree tree for and anchor tag".

Answer 2

Is there any particular identifier for the td or th you want?
But if you want tr element for table with class infobox similar to your code, here is what I would do:
require(rvest)
# read the webpage
webpage <- read_html("https://en.wikipedia.org/wiki/Los_Angeles")
# extract the url-link element of table with class infobox
your_infobox_tr <- webpage %>% html_nodes(".infobox") %>% html_nodes(".url>a")
# extract the href link content
your_href <- your_infobox_tr %>% html_attr(name='href')
Or if you like a one-liner
your_wanted_link <- read_html("https://en.wikipedia.org/wiki/Los_Angeles") %>% html_nodes(".infobox") %>% html_nodes(".url>a") %>% html_attr(name="href")
FYI: if you do not know what %>% is, it is a pipe operator which can be obtained by installing magrittr package.