Help with regular expression
ryan
block and replace it with ''. This is because when I'm showing snippets
of a post, I don't want a piece of code to be in the snippet. Anyway,
here's what I'm doing:
# works perfect (only for pre)
def strip_pre_block
text.gsub(/<pre>[^<]*<\/pre>/,'')
end
Now, I want to do the same with blockquote. How can I combine the two?
Something like this:
# doesn't work at all (for either one)
def strip_pre_and_quote_blocks
text.gsub(/(^<pre>[^<]*<\/pre>$|^<blockquote>.*<\/blockquote>$)/,'')
end
When I try that, it doesn't replace either one of the "pre" or
"blockquote" blocks with '', but the first method works perfect for the
"pre" block only. I can't even get the blockquote one to work by
itself.
Can someone help out with this??? Thanks in advance...
--
Posted via http://www.ruby-forum.com/.
ryan
<blockquote>
<p>Quote goes here</p>
</blockquote>
I may have been ignoring the "p" tags so it didn't work.
Still can't get it. Any help is greatly appreciated.
Phlip
> # doesn't work at all (for either one)
> def strip_pre_and_quote_blocks
> text.gsub(/(^<pre>[^<]*<\/pre>$|^<blockquote>.*<\/blockquote>$)/,'')
> end
Here are some general suggestions. Write a test case for this regexp, have
it print out a result, and run it over and over again as you incrementally
add elements. I note this because you appear to have leapt directly from a
simple to a complex regexp without incrementally examining the reaction to
each individual symbol. Get used to writing test cases as experiments, and
frequently running them (with one keystroke preferrably).
Next, put the ^ and $ outside the (), on principle.
Next, try (<pre>|<blockquote>).
Next, [^<]* is always tempting, but you can get less greedy IIRC with .*?.
That will look-ahead a little more.
Next, post this to a Ruby or Regex newsgroup, because it's not about Rails.
Next, treat your HTML as XHTML and parse it with REXML. You can use XPath to
reach in and nab each pre, and change its tag or contents to whatever you
want. Then write it all back as XHTML.
Next, each < probably needs an escape, like \<
> When I try that, it doesn't replace either one of the "pre" or
> "blockquote" blocks with '', but the first method works perfect for the
> "pre" block only. I can't even get the blockquote one to work by
> itself.
You could run two gsubs; one with <pre> and one with <blockquote>.
To strip, you could just yank all 4 items with 4 gsubs, too.
--
Phlip
http://www.greencheese.us/ZeekLand <-- NOT a blog!!!
Rob Biedenharn
If you're trying to get rid of just the tags, then this might work.
However, if you intend to remove the content between the tags, too
("The <pre>stuff doesn't</pre> work" => "The work"), then you either
need to specifically match the newlines or just use the 'm' modifier
on your regexp to use multi-line mode.
If you want to remove <pre> and <blockquote> along with the contents
(inner_html) of those, then you can try something like this:
irb>> regexp = %r{<(pre|blockquote)\b[^>]*>.*?</\1>}m
=> /<(pre|blockquote)\b[^>]*>.*?<\/\1>/m
irb>> html_fragment = <<EOF
And then someone said:
<blockquote>
When I try that, it doesn't replace either one of the "pre" or
"blockquote" blocks with '', but the first method works perfect for the
"pre" block only. I can't even get the blockquote one to work by
itself.
</blockquote>
So I told them to use this code:
<pre class="ruby">
regexp = %r{<(pre|blockquote)\\b[^>]*>.*?</\\1>}m
my_string = <<-EOS
And then someone said:
<blockquote>
When I try that, it doesn't replace either one of the "pre" or
"blockquote" blocks with '', but the first method works perfect for the
"pre" block only. I can't even get the blockquote one to work by
itself.
</blockquote>
EOS
my_string.gsub!(regexp, '...')
</pre>
<blockquote>
When I try that, it doesn't replace either one of the "pre" or
"blockquote" blocks with '', but the first method works perfect for the
"pre" block only. I can't even get the blockquote one to work by
itself.
</blockquote>
So I told them to use this code:
<pre class="ruby">
regexp = %r{<(pre|blockquote)\\b[^>]*>.*?</\\1>}m
my_string = <<-EOS
And then someone said:
<blockquote>
When I try that, it doesn't replace either one of the "pre" or
"blockquote" blocks with '', but the first method works perfect for the
"pre" block only. I can't even get the blockquote one to work by
itself.
</blockquote>
EOS
my_string.gsub!(regexp, '...')
</pre>
EOF
=> "And then someone said:\n<blockquote>\nWhen I try that, it doesn't
replace either one of the \"pre\" or\n\"blockquote\" blocks with '',
but the first method works perfect for the\n\"pre\" block only. I
can't even get the blockquote one to work by\nitself.\n</blockquote>
\nSo I told them to use this code:\n<pre class=\"ruby\">\n regexp = %
r{<(pre|blockquote)\\b[^>]*>.*?</\\1>}m\n my_string = <<-EOS\nAnd
then someone said:\n<blockquote>\nWhen I try that, it doesn't replace
either one of the \"pre\" or\n\"blockquote\" blocks with '', but the
first method works perfect for the\n\"pre\" block only. I can't even
get the blockquote one to work by\nitself.\n</blockquote>\n EOS\n
my_string.gsub!(regexp, '...')\n</pre>\n"
irb>> html_fragment.gsub(regexp, '...')
=> "And then someone said:\n...\nSo I told them to use this code:\n...
\n"
irb>> puts _
And then someone said:
...
So I told them to use this code:
...
=> nil
irb>>
In addition to using an XML parser as Philip suggests, you might want
to actually read about regular expressions. You can start with the
pickaxe (Programming Ruby, The Pragmatic Programmers' Guide, 2nd ed.)
pages 68-70, 324-328, 600-603.
-Rob
Rob Biedenharn http://agileconsultingllc.com
R...@AgileConsultingLLC.com
Mark Thomas
I agree with Phlip. This has crossed into territory better served by a
real HTML parser. Something like this (untested):
require 'hpricot'
doc =
Hpricot("Keep<pre>Toss</pre>Keep<blockquote>Toss<p>Toss</p>Toss</blockquote>")
doc.search("//pre").each do |pre|
pre.remove
end
doc.search("//blockquote").each do |bq|
bq.remove
end
puts doc