循环遍历 R 中的 csv 文件

Question

I need to get the results from all formula 1 races from the year 2021. Here I would like to loop through all of these url's and read the files. You can see my current code below. The url's are nearly the same, only the x here "http://ergast.com/api/f1/2021/x/driverStandings" changes for example. Is there a way to? Thank you very much in advance!

baseurl = "http://ergast.com/api/f1/2021/"

results
x=1
while (x <= 22) 
{
baseurl = baseurl + x + "/driverStandings"
data = GET(baseurl)
x = x+1

}

Answer 1

library(tidyverse)
library(xml2)

get_races <- function(round) {
  data <- paste0("https://ergast.com/api/f1/2021/",
                 round,
                 "/driverStandings") %>%
    read_xml() %>%
    xml_ns_strip()
  
  df <- tibble(
    position = data %>%
      xml_child() %>%
      xml_child() %>%
      xml_children() %>%
      xml_attr("position") %>%
      as.numeric(),
    name = data %>% xml_find_all(xpath = "//GivenName") %>%
      xml_text() %>%
      paste(data %>% xml_find_all(xpath = "//FamilyName") %>%
              xml_text()),
    constructor = data %>%
      xml_find_all(xpath = "//Name") %>%
      xml_text(),
    points = data %>%
      xml_child() %>%
      xml_child() %>%
      xml_children() %>%
      xml_attr("points") %>%
      as.numeric(),
    wins = data %>%
      xml_child() %>%
      xml_child() %>%
      xml_children() %>%
      xml_attr("wins") %>%
      as.numeric(),
    season = data %>%
      xml_child() %>%
      xml_attr("season") %>%
      as.numeric(),
    round = data %>%
      xml_child() %>%
      xml_attr("round") %>%
      as.numeric()
  )
  return(df)
}

Get all races from 1 to 22

all_races <- map_dfr(1:22, get_races)

# A tibble: 450 × 7
   position name             constructor  points  wins season round
      <dbl> <chr>            <chr>         <dbl> <dbl>  <dbl> <dbl>
 1        1 Lewis Hamilton   Mercedes         25     1   2021     1
 2        2 Max Verstappen   Red Bull         18     0   2021     1
 3        3 Valtteri Bottas  Mercedes         16     0   2021     1
 4        4 Lando Norris     McLaren          12     0   2021     1
 5        5 Sergio Pérez     Red Bull         10     0   2021     1
 6        6 Charles Leclerc  Ferrari           8     0   2021     1
 7        7 Daniel Ricciardo McLaren           6     0   2021     1
 8        8 Carlos Sainz     Ferrari           4     0   2021     1
 9        9 Yuki Tsunoda     AlphaTauri        2     0   2021     1
10       10 Lance Stroll     Aston Martin      1     0   2021     1
# … with 440 more rows