R 使用下拉菜单抓取 [英] R scraping with a dropdown menu
问题描述
我试图从网站上抓取 NBA 每日 ROS 预测:
I am attempting to scrape the NBA daily ROS projections from the site:https://hashtagbasketball.com/fantasy-basketball-projections.
Problem is the default number of players selected is 200, I would want 400 (or ALL would work too).
This code retrieves the first 200 no problem:
> url <- 'https://hashtagbasketball.com/fantasy-basketball-projections'
>
> page <- read_html(url)
>
> projs <- html_table(page)[[3]] %>% ### anything after this just cleans the df
+ rename_all(~gsub('3pm','threes',gsub('\\%','pct',tolower(.)))) %>%
+ mutate_at(vars(matches('pct$')),~stringr::str_sub(.,1,4)) %>%
+ mutate(player = stringr::word(player,1, 2, sep = ' ')) %>%
+ mutate(pos = stringr::word(pos,1,1,sep = ',')) %>%
+ mutate(pos2 = gsub('P','',pos)) %>%
+ drop_na(player) %>%
+ mutate_at(vars(-c(player,matches('pos'),team)),~as.numeric(.)) %>%
+ select(player, matches('pos'),everything(),-`r#`) %>%
+ head(2)
> projs
player pos pos2 team gp mpg fgpct ftpct threes pts treb ast stl blk to total
1 James Harden PG G HOU 64 36.3 0.44 0.86 4.7 34.4 6.6 9.3 1.7 0.8 4.6 17.68
2 Anthony Davis PF F LAL 65 34.8 0.50 0.84 1.3 26.6 9.4 3.2 1.5 2.3 2.5 14.56
That creates a table with all desired categories. However, when I use the code below does not extract all the statistical categories (only gp and mpg):
> pgsession <- html_session(url)
> pgform <-html_form(pgsession)[[1]]
> filled_form <-set_values(pgform,
+ "ctl00$ContentPlaceHolder1$DDSHOW" = "400")
>
> d <- submit_form(session=pgsession, form=filled_form)
Submitting with '<unnamed>'
>
> y <- d %>%
+ html_nodes("table") %>%
+ .[[3]] %>%
+ html_table(header=TRUE) %>%
+ mutate(PLAYER = stringr::word(PLAYER,1, 2, sep = ' ')) %>%
+ head(2)
> y
R# PLAYER POS TEAM GP MPG TOTAL
1 1 James Harden PG,SG HOU 64 36.3 0.00
2 2 Anthony Davis PF,C LAL 65 34.8 0.00
Any idea what I'm doing wrong? Thanks
The problem seems to be that the check boxes for those other variables are not checked when you submit your form. You will have to set them manually. This shows you how to get ftm
and ftpct
. I will leave the rest to you:
library(tidyverse)
library(rvest)
url <- 'https://hashtagbasketball.com/fantasy-basketball-projections'
pgsession <- html_session(url)
pgform <-html_form(pgsession)
pgform[[1]][[5]][["ctl00$ContentPlaceHolder1$CBFTM"]]$value <- "checked"
pgform[[1]][[5]][["ctl00$ContentPlaceHolder1$CBFTP"]]$value <- "checked"
filled_form <-set_values(pgform[[1]],"ctl00$ContentPlaceHolder1$DDSHOW" = "400")
d <- submit_form(session=pgsession, form=filled_form)
d %>%
html_nodes("table") %>%
.[[3]] %>%
html_table() %>%
rename_all(~gsub('3pm','threes',gsub('\\%','pct',tolower(.)))) %>%
mutate_at(vars(matches('pct$')),~stringr::str_sub(.,1,4)) %>%
mutate(player = stringr::word(player,1, 2, sep = ' ')) %>%
mutate(pos = stringr::word(pos,1,1,sep = ',')) %>%
mutate(pos2 = gsub('P','',pos)) %>%
drop_na(player) %>%
mutate_at(vars(-c(player,matches('pos'),team)),~as.numeric(.)) %>%
select(player, matches('pos'),everything(),-`r#`) %>%
head(2)
# player pos pos2 team gp mpg ftm ftpct total
#1 James Harden PG G HOU 64 36.3 10.4 0.86 10.95
#2 Devin Booker SG SG PHX 70 35.6 6.7 0.91 7.99
In case you weren't aware, you can get the checkbox names by right clicking and choosing "Inspect" in Chrome:
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