I'm trying to store regexes in a database but they're not working when used in a .sub(), even though the same regex works when used directly in .sub() as a string.
regex = Class.object.field // Class.object is an active record containing "\w*\s\/\s"
mystring = "first / second"
mystring.sub(/#{regex}/, '')
// => nil
mystring.sub(/\w*\s\/\s/, '')
// => second
Any insight appreciated!
Thanks,
Matt.
Editing to correct class/object terminology (thanks) & correcting my 2nd example as I had shown #{} wrapped around the working regex (cut & paste SNAFU).
To answer your question: It is not quite what kind of thing your Class.object is. If it's an ActiveRecord, it won't work.
Edit: You obviously found that the problem is Rails escaping the regexp.
An ActiveRecord cannot "contain" your regular expression directly; the regexp will be in one of the fields of your record. In which case you'd want to do something like regexp = Class.object.field_containing_the_regexp.
Even if that is not the case, I suspect that the problem is that your regexp is something other than a string. You can quickly test this by using
puts "My regexp: #{regexp}"
The string that you will see in the output will be the one that is used for the regexp.
A String is not a Regexp. You have to create a Regexp object first.
regex = Regexp.new("\w*\s\/\s")
Turns out my regexp didn't cater for all cases - \w didn't account for symbols. After checking in rails console, and seeing the screwey escaping I was alreasdy half-way down the wrong track.
Thanks for the help.
Related
I have a value called "FooBar". I want to replace this text with the quotes to Enr::Rds::FooBar without quotes.
Update:
For example, #question.answer_model gives the value "FooBar" (with the quotes)
I am a newbie and somebody please refer me how would i start to know about regex? What is the best way to practice in online?
Since you want to: a) drop the quotes and b) prepend FooBar with Enr::Rds::, I would suggest you preform exactly what is intended, literally:
'"FooBar"'.delete('"').gsub(/\A/, "Enr::Rds::")
# => "Enr::Rds::FooBar"
I think you are trying to convert a string to a constant. try the following
"Enr::Rds::#{#question.answer_model.gsub('"', '')}".constantize.find(...)
I am getting text from a feed that has alot of characters like:
Insignia™ 2.0 Stereo Computer Speaker System (2-Piece) - Black
4th-Generation Apple® iPod® touch
Is there an easy way to get rid of these, or do I have to anticipate which characters I want to delete and use the delete method to remove them? Also, when I try to remove
&
with
str.delete("&")
It leaves behind "amp;" Is there a better way to delete this type of character? Do I need to re-encode the text?
String#delete is certainly not what you want, as it works on characters, not the string as a whole.
Try
str.gsub /&/, ""
You may also want to try replacing the & with a literal ampersand, such as:
str.gsub /&/, "&"
If this is closer to what you really want, you may get the best results unescaping the HTML string. If so try this:
CGI::unescapeHTML(str)
Details of the unescapeHTML method are here.
If you are getting data from a 'feed', aka RSS XML, then you should be using an XML parser like Nokogiri to process the XML. This will automatically unescape HTML entities and allow you to get the proper string representation directly.
For removing try to use gsub method, something like this:
text = "foo&bar"
text.gsub /\b&\b/, "" #=> foobar
I'm building an app in Rails 3 and I need a method to extract all urls from a string and store them in a hash or something. I know I need to use regular expressions but I don't know where exactly to begin with them.
Also, I know about auto_link, but it doesn't quite do what I'm trying to achieve. I just simply need a hash of all the url's from a string.
Thanks!
From http://www.regular-expressions.info/ruby.html
"To collect all regex matches in a string into an array, pass the regexp object to the string's scan() method, e.g.: myarray = mystring.scan(/regex/)."
So you probably need strings that start with "http". So check the docs for that :)
I don't program in Ruby and I'm not very good with regex but maybe this will help you out:
http://www.ozzu.com/programming-forum/url-regex-t104809.html
I am creating a parser that wards off against spamming and harvesting of emails from a block of text that comes from tinyMCE (so it may or may not have html tags in it)
I've tried regexes and so far this has been successful:
/\b[A-Z0-9._%+-]+#[A-Z0-9.-]+\.[A-Z]{2,4}\b/i
problem is, i need to ignore all email addresses with mailto hrefs. for example:
test#mail.com
should only return the second email add.
To get a background of what im doing, im reversing the email addresses in a block so the above example would look like this:
moc.liam#tset
problem with my current regex is that it also replaces the one in href. Is there a way for me to do this with a single regex? Or do i have to check for one then the other? Is there a way for me to do this just by using gsub or do I have to use some nokogiri/hpricot magicks and whatnot to parse the mailtos? Thanks in advance!
Here were my references btw:
so.com/questions/504860/extract-email-addresses-from-a-block-of-text
so.com/questions/1376149/regexp-for-extracting-a-mailto-address
im also testing using this:
http://rubular.com/
edit
here's my current helper code:
def email_obfuscator(text)
text.gsub(/\b[A-Z0-9._%+-]+#[A-Z0-9.-]+\.[A-Z]{2,4}\b/i) { |m|
m = "<span class='anti-spam'>#{m.reverse}</span>"
}
end
which results in this:
<a target="_self" href="mailto:<span class='anti-spam'>moc.liamg#tset</span>"><span class="anti-spam">moc.liamg#tset</span></a>
Another option if lookbehind doesn't work:
/\b(mailto:)?([A-Z0-9._%+-]+#[A-Z0-9.-]+\.[A-Z]{2,4})\b/i
This would match all emails, then you can manually check if first captured group is "mailto:" then skip this match.
Would this work?
/\b(?<!mailto:)[A-Z0-9._%+-]+#[A-Z0-9.-]+\.[A-Z]{2,4}\b/i
The (?<!mailto:) is a negative lookbehind, which will ignore any matches starting with mailto:
I don't have Ruby set up at work, unfortunately, but it worked with PHP when I tested it...
Why not just store all the matched emails in an array and remove any duplicates? You can do this easily with the ruby standard library and (I imagine) it's probably quicker/more maintainable than adding more complexity to your regex.
emails = ["email_one#example.com", "email_one#example.com", "email_two#example.com"]
emails.uniq # => ["email_one#example.com", "email_two#example.com"]
I am somewhat of a Rails newbie so bear with me, I have most of the application figured out except for this one part.
def linkup_mentions_and_hashtags(text)
text.gsub!(/#([\w]+)(\W)?/, '#\1\2')
text.gsub!(/#([\w]+)(\W)?/, '#\1\2')
text
end
I found this example here: http://github.com/jnunemaker/twitter-app
The link to the helper method: http://github.com/jnunemaker/twitter-app/blob/master/app/helpers/statuses_helper.rb
Perhaps you could use Regular Expressions to look for "#..." and then replace the matches with the corresponding link?
You could use a regular expression to search for #sometext{whitespace_or_endofstring}
You can use regular expressions, i don't know ruby but the code should be almost exactly as my example:
Regex.Replace("this is an example #AlbertEin",
"(?<type>[##])(?<nick>\\w{1,}[^ ])",
"${type}${nick}");
This example would return
this is an example <a href="http://twitter.com/AlbertEin>#AlbertEin</a>
If you run it on .NET
The regex (?<type>[##])(?<nick>\\w{1,}[^ ]) means, capture and name it TYPE the text that starts with # or #, and then capture and name it NAME the text that follows that contains at least one text character until you fin a white space.
Perhaps you can use a regular expression to parse out the words starting with #, then update the string at that location with the proper link.
This regular expression will give you words starting with # symbols, but you might have to tweak it:
\#[\S]+\
You would use a regular expression to search for #username and then turn that to the corresponding link.
I use the following for the # in PHP:
$ret = preg_replace("#(^|[\n ])#([^ \"\t\n\r<]*)#ise",
"'\\1<a href=\"http://www.twitter.com/\\2\" >#\\2</a>'",
$ret);
I've also been working on this, I'm not sure that it's 100% perfect, but it seems to work:
def auto_link_twitter(txt, options = {:target => "_blank"})
txt.scan(/(^|\W|\s+)(#|#)(\w{1,25})/).each do |match|
if match[1] == "#"
txt.gsub!(/##{match.last}/, link_to("##{match.last}", "http://twitter.com/search/?q=##{match.last}", options))
elsif match[1] == "#"
txt.gsub!(/##{match.last}/, link_to("##{match.last}", "http://twitter.com/#{match.last}", options))
end
end
txt
end
I pieced it together with some google searching and some reading up on String.scan in the api docs.