如何下载含数字开头年份文件的文件夹？rvest下载Zip变量为空求助

First, let's tackle why your zips variable is empty—you've got a small typo in your code, plus a couple of tweaks to make it more reliable:

1. Correct the Variable Name & Selector #

You assigned the parsed HTML to rh, but then tried to use an undefined pg variable in html_nodes(pg, ...)—that's the main reason nothing was found. Let's fix that, plus adjust the selector to target all ZIP files directly (more robust than filtering by the year prefix):

library(rvest)
library(purrr) # For easy iteration over files

# Base URL of the folder
base_url <- "https://danepubliczne.imgw.pl/data/dane_pomiarowo_obserwacyjne/dane_meteorologiczne/dobowe/synop/2011/"

# Parse the webpage
page <- read_html(base_url)

# Extract all links pointing to ZIP files
zips <- page %>%
  html_elements("a[href$='.zip']") %>% # Target links ending with .zip
  html_attr("href")

Now zips should contain all the ZIP filenames from the page.

2. Download All ZIP Files to a Local Folder #

Once you have the list of ZIPs, combine each filename with the base URL and download them to an organized local folder:

# Create a local folder to store downloads (if it doesn't exist)
local_folder <- "imgw_2011_synop_data"
if (!dir.exists(local_folder)) dir.create(local_folder)

# Download each file (add a small delay to avoid overwhelming the server)
walk(zips, function(zip_file) {
  file_url <- paste0(base_url, zip_file)
  local_path <- file.path(local_folder, zip_file)
  download.file(file_url, local_path, mode = "wb") # mode="wb" for binary files
  Sys.sleep(0.5) # Optional polite delay to prevent hitting server limits
})

Web servers typically don't support direct "folder downloads" via browser or R, but the method above effectively replicates that by:

1. Scraping all relevant file links from the folder's webpage
2. Downloading each file individually to a local folder

If you're comfortable with command-line tools, you can also use wget (available on most operating systems) to do this in one line:

wget -r -np -A.zip https://danepubliczne.imgw.pl/data/dane_pomiarowo_obserwacyjne/dane_meteorologiczne/dobowe/synop/2011/

• -r: Enable recursive download
• -np: Don't traverse to parent directories
• -A.zip: Only download files ending with .zip

内容的提问来源于stack exchange，提问作者Tom