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Get URL subdomains

Source: R/accessors.R
get_subdomain.Rd

Extracts the subdomain component of a URL.

Usage

get_subdomain(
  url,
  protocol_handling = "keep",
  www_handling = "none",
  source = c("all", "private", "icann"),
  include_www = FALSE,
  format = c("string", "labels"),
  host_encoding = c("keep", "idna", "unicode")
)

Arguments

url

A character vector of URLs.

protocol_handling

A character string specifying how to handle protocols. Defaults to "keep".

  • "keep": If a scheme exists (http, https, ftp, ftps), it's used. If no scheme, "http://" is added.

  • "none": If a scheme exists, it's used. If no scheme, then no scheme is used (scheme component will be NA).

  • "strip": Any existing scheme is removed (scheme component will be NA).

  • "http": The scheme is forced to be "http".

  • "https": The scheme is forced to be "https".

www_handling

A character string specifying how to handle "www" and "www[number]" prefixes in the host. Defaults to "none".

  • "none": (Default) Leaves the host's www prefix (or lack thereof) untouched.

  • "strip": Removes any "www." or "www[number]." prefix.

  • "keep": Ensures the host starts with "www.". If it has "www[number].", it's normalized to "www.". If no www prefix, "www." is added. An empty input host remains empty.

  • "if_no_subdomain": If the host is a bare registered domain (e.g., "example.com"), "www." is added. If the host already has a "www." or "www[number]." prefix, it is normalized to "www." (e.g., "www1.example.com" becomes "www.example.com"; "www1.sub.example.com" becomes "www.sub.example.com"). If a non-www subdomain exists (e.g., "sub.example.com" or the normalized "www.sub.example.com"), the host is not further altered. An empty input host remains empty.

source

Which PSL source to use: "all", "private", or "icann".

include_www

Logical; if FALSE (default), removes a leading www/www[0-9]* label only when it is the sole subdomain label.

format

Return format: "string" (default) or "labels" for a character vector of labels.

host_encoding

How to present the host in `clean_url`. Defaults to "keep".

  • "keep": Leave host as parsed by curl (may preserve original case).

  • "idna": Convert Unicode host labels to Punycode (IDNA) for the cleaned URL.

  • "unicode": Decode Punycode labels to Unicode for the cleaned URL.

Value

A character vector (format="string") or list of label vectors (format="labels").

Examples

get_subdomain("http://www.blog.example.co.uk")
#> [1] "www.blog"
get_subdomain("http://www.blog.example.co.uk", format = "labels")
#> [[1]]
#> [1] "www"  "blog"
#>