Read HTML or XML.
read_xml(x, encoding = "", ..., as_html = FALSE,
options = "NOBLANKS")read_html(x, encoding = "", ..., options = c("RECOVER", "NOERROR",
"NOBLANKS"))
# S3 method for character
read_xml(x, encoding = "", ..., as_html = FALSE,
options = "NOBLANKS")
# S3 method for raw
read_xml(x, encoding = "", base_url = "", ...,
as_html = FALSE, options = "NOBLANKS")
# S3 method for connection
read_xml(x, encoding = "", n = 64 * 1024,
verbose = FALSE, ..., base_url = "", as_html = FALSE,
options = "NOBLANKS")
A string, a connection, or a raw vector.
A string can be either a path, a url or literal xml. Urls will
be converted into connections either using base::url
or, if
installed, curl::curl
. Local paths ending in .gz
,
.bz2
, .xz
, .zip
will be automatically uncompressed.
If a connection, the complete connection is read into a raw vector before being parsed.
Specify a default encoding for the document. Unless otherwise specified XML documents are assumed to be in UTF-8 or UTF-16. If the document is not UTF-8/16, and lacks an explicit encoding directive, this allows you to supply a default.
Additional arguments passed on to methods.
Optionally parse an xml file as if it's html.
Set parsing options for the libxml2 parser. Zero or more of
recover on errors
substitute entities
load the external subset
default DTD attributes
validate with the DTD
suppress error reports
suppress warning reports
pedantic error reporting
remove blank nodes
use the SAX1 interface internally
Implement XInclude substitition
Forbid network access
Do not reuse the context dictionary
remove redundant namespaces declarations
merge CDATA as text nodes
do not generate XINCLUDE START/END nodes
compact small text nodes; no modification of the tree allowed afterwards (will possibly crash if you try to modify the tree)
parse using XML-1.0 before update 5
do not fixup XINCLUDE xml:base uris
relax any hardcoded limit from the parser
parse using SAX2 interface before 2.7.0
ignore internal document encoding hint
Store big lines numbers in text PSVI field
When loading from a connection, raw vector or literal html/xml, this allows you to specify a base url for the document. Base urls are used to turn relative urls into absolute urls.
If file
is a connection, the number of bytes to read per
iteration. Defaults to 64kb.
When reading from a slow connection, this prints some output on every iteration so you know its working.
An XML document. HTML is normalised to valid XML - this may not be exactly the same transformation performed by the browser, but it's a reasonable approximation.
When performing web scraping tasks it is both good practice --- and often required ---
to set the user agent request header
to a specific value. Sometimes this value is assigned to emulate a browser in order
to have content render in a certain way (e.g. Mozilla/5.0 (Windows NT 5.1; rv:52.0) Gecko/20100101 Firefox/52.0
to emulate more recent Windows browsers). Most often,
this value should be set to provide the web resource owner information on who you are
and the intent of your actions like this Google scraping bot user agent identifier:
Googlebot/2.1 (+http://www.google.com/bot.html)
.
You can set the HTTP user agent for URL-based requests using httr::set_config()
and httr::user_agent()
:
httr::set_config(httr::user_agent("me@example.com; +https://example.com/info.html"))
httr::set_config()
changes the configuration globally,
httr::with_config()
can be used to change configuration temporarily.
# NOT RUN {
# Literal xml/html is useful for small examples
read_xml("<foo><bar /></foo>")
read_html("<html><title>Hi<title></html>")
read_html("<html><title>Hi")
# From a local path
read_html(system.file("extdata", "r-project.html", package = "xml2"))
# }
# NOT RUN {
# From a url
cd <- read_xml(xml2_example("cd_catalog.xml"))
me <- read_html("http://had.co.nz")
# }
Run the code above in your browser using DataLab