How to detect with python if the string contains html code?

static picture static · Jul 21, 2014 · Viewed 21.3k times · Source

How to detect either the string contains an html (can be html4, html5, just partials of html within text)? I do not need a version of HTML, but rather if the string is just a text or it contains an html. Text is typically multiline with also empty lines

Update:

example inputs:

html:

<head><title>I'm title</title></head>
Hello, <b>world</b>

non-html:

<ht fldf d><
<html><head> head <body></body> html

Answer

alecxe picture alecxe · Jul 21, 2014

You can use an HTML parser, like BeautifulSoup. Note that it really tries it best to parse an HTML, even broken HTML, it can be very and not very lenient depending on the underlying parser:

>>> from bs4 import BeautifulSoup
>>> html = """<html>
... <head><title>I'm title</title></head>
... </html>"""
>>> non_html = "This is not an html"
>>> bool(BeautifulSoup(html, "html.parser").find())
True
>>> bool(BeautifulSoup(non_html, "html.parser").find())
False

This basically tries to find any html element inside the string. If found - the result is True.

Another example with an HTML fragment:

>>> html = "Hello, <b>world</b>"
>>> bool(BeautifulSoup(html, "html.parser").find())
True

Alternatively, you can use lxml.html:

>>> import lxml.html
>>> html = 'Hello, <b>world</b>'
>>> non_html = "<ht fldf d><"
>>> lxml.html.fromstring(html).find('.//*') is not None
True
>>> lxml.html.fromstring(non_html).find('.//*') is not None
False