replacing html tag and its content using ruby gsub - ruby

Question

I am trying to replace a <p>..</p> tag content in html content with empty string by doing the following.
string = \n <img alt=\"testing artice breaking news\" src=\"something.com" />\n <p>\n \tnew vision content for testing rss feeds\n </p>\n "
When I did
string.gsub!(/<p.*?>|<\/p>/, '')
It just replaced the <p> and </p> with empty string but the content remained. How can I remove both the tag and its content ?

Answer 1

Apparently, your regex does not match <p>...</p> (<p> and its content). Try this:
string.gsub!(/<p>.*<\/p>/, '')
test = '\n <img alt=\"testing artice breaking news\" src=\"something.com" />\n <p>\n \tnew vision content for testing rss feeds\n </p>\n "'
test.gsub(/<p>.*<\/p>/, '')
Return
"\\n <img alt=\\\"testing artice breaking news\\\" src=\\\"something.com\" />\\n \\n \""
Also, please consider #Tom Lord's comment, you can use Nokogiri to manipulate HTML.

Answer 2

First of all, consider using HTML parsers when parsing HTML, see How do I remove a node with Nokogiri?.
If you want to do it with a regex, you can use
string.gsub(/<p(?:\s[^>]*)?>.*?<\/p>/m, '')
See the Rubular regex demo. This will work with tags that cannot be nested. Details:
<p(?:\s[^>]*)?> - <p, and an optional sequence of a whitespace and zero or more chars other than > (as many as possible), and then >
.*? - due to /m, any zero or more chars as few as possible
<\/p> - </p> string.
If the tags can be nested, you still can use a regex:
tagname = "p"
rx = /<#{tagname}(?:\s[^>]*)?>(?:[^<]*(?:<(?!#{tagname}[\s>]|\/#{tagname}>)[^<]*)*|\g<0>)*<\/#{tagname}>/
p string.gsub(rx, '')
# => "\n <img alt=\"testing artice breaking news\" src=\"something.com\" />\n \n"
See the Rubular regex demo. Details:
<#{tagname} - < and tag name
(?:\s[^>]*)?> - an optional sequence of whitespace and then zero or more chars other than <
(?:[^<]*(?:<(?!#{tagname}[\s>]|\/#{tagname}>)[^<]*)*|\g<0>)* - zero or more occurrences of
(?:[^<]*(?:<(?!#{tagname}[\s>]|\/#{tagname}>)[^<]*)* - zero or more chars other than < and then zero or more sequences of < that is not followed with tag name + > or whitespace or / + tag name + > followed with zero or more chars other than < chars
|
\g<0> - the whole regex pattern recursed
<\/#{tagname}> - </ + tag name + >.
See a Ruby demo:
string = "\n <img alt=\"testing artice breaking news\" src=\"something.com\" />\n <p>\n \tnew vision content for testing rss feeds\n </p>\n"
p string.gsub(/<p(?:\s[^>]*)?>.*?<\/p>/m, '')
tagname = "p"
rx = /<#{tagname}(?:\s[^>]*)?>(?:[^<]*(?:<(?!#{tagname}[\s>]|\/#{tagname}>)[^<]*)*|\g<0>)*<\/#{tagname}>/m
p string.gsub(rx, '')```
# => "\n <img alt=\"testing artice breaking news\" src=\"something.com\" />\n \n"