时间戳

首页 > 解决方案 > 遍历 url 列表并下载 html 表 R

r - 遍历 url 列表并下载 html 表 R

问题描述

我正在尝试从篮球参考下载球员信息。

我有一个 csv，我已将其作为数据框 (data_allplayers) 导入，它有两列，一列带有 url，另一列带有我想将该文件另存为的名称。

https://www.basketball-reference.com/players/g/gordoaa01/gamelog/2020
Aaron Gordon
2
https://www.basketball-reference.com/players/h/holidaa01/gamelog/2020
Aaron Holiday
3
https://www.basketball-reference.com/players/n/naderab01/gamelog/2020
Abdel Nader

等529行。

我想遍历它并将该位置的每个 url 和主数据表保存到一个数据框，然后将其与玩家姓名一起存储。

我可以完美下载这些表格，但我手动/单独使用：

#player1  
webpage <- read_html("https://www.basketball-reference.com/players/g/gordoaa01/gamelog/2020")
tbls <- html_nodes(webpage, "table") %>% 
  html_table(fill = TRUE)
Aaron_Gordon <- as.data.frame(tbls[8])

但是我不喜欢使用列表中已经填充的 url 将它变成一个循环。我尝试过的完整代码如下，非常感谢任何帮助！

# Load libraries
library(dplyr) 
library(readxl)
library(rvest)
library(data.table) 
library(readr)
library(plyr)



data_allplayers <- read_csv("NBA_rebounds - players1.csv")
#delete the unwanted columns, add headers
data_allplayers <- select(data_allplayers, url, full_name)
header <- c("url", "name")
setnames(data_allplayers, header)
#removes first row
data_allplayers <- data_allplayers[-c(1), ]


#attempt at loop that doesn't work

for(i in 1:nrow(data_allplayers)){
  webpage <- read_html(data_allplayers$url[[i,]])
  tbls <- html_nodes(webpage, "table") %>% 
    html_table(fill = TRUE)
  Data_scrape <- as.data.frame(tbls[8])
  Report1_Name <- data_allplayers$name[[i,]]
  write.csv(Data_scrape, paste0(Report1_Name,".csv"))
}

标签： rloopsweb-scraping

解决方案

这是一种方法Map：

library(rvest)

Map(function(x, y) {
  read_html(x) %>%
    html_nodes('table') %>%
    html_table(fill = TRUE) %>%
    .[[8]] %>%
    write.csv(paste0(y, '.csv'), row.names = FALSE)
}, data_allplayers$url, data_allplayers$name)

对于您共享的 3 个值，这对我来说很好。

data_allplayers <- structure(list(url = c("https://www.basketball-reference.com/players/g/gordoaa01/gamelog/2020 ", 
"https://www.basketball-reference.com/players/h/holidaa01/gamelog/2020 ", 
"https://www.basketball-reference.com/players/n/naderab01/gamelog/2020 "
), name = c(" Aaron Gordon", " Aaron Holiday", " Abdel Nader"
)), class = "data.frame", row.names = c(NA, -3L))

推荐阅读