why does this hashtag regex extraction leave this in the front? "--- -"

Question

Here's the regex that I'm using for hashtag extraction

def extract_hashtags
       hashtag_regex = /\B#(\w+)/i
       text_hashtags = content.scan(hashtag_regex)
       text_hashtags.each do |tag|
         hashtags.create hashtags: tag
       end
     end

Using /\B#(\w+)/i, leaves this in the front of the data

For example, the extraction should be "abcd", but it is saved as "--- - abcd"

What should the regex be change to in order to extract just the #abcd?

If the post content (where the hashtag is extracted) is something like "Hello stackoverflow #stackoverflow", it gets saved into the database as "-- - stackoverflow"

I tried without \B and tried to extract "#checkme" from a post, but I got "--- - checkme" — user2159586, May 01 '13 at 05:50
`>> "Hello stackoverflow #stackoverflow".scan(/\B#(\w+)/i) => [["stackoverflow"]]` — Joachim Isaksson, May 01 '13 at 05:50

score 4 · Accepted Answer · answered May 01 '13 at 05:51

test = "Hello stackoverflow #stackoverflow"
test.scan( /\B#(\w+)/i )
 => [["stackoverflow"]]

I suspect you are storing the array ["stackoverflow"], and from the resulting string, is your storage using YAML to handle structured data?

I think you just want to alter the create line:

text_hashtags.each do |tag|
  hashtags.create hashtags: tag[0]
end

score 2 · Answer 2 · answered May 01 '13 at 05:52

The "--- -" is prepended by the database layer of Rails when converting the array to YAML. "---" is the YAML prefix, and "-" indicates the first element of the array.

When you read it back from the database, Rails will do the inverse transformation: it will rebuild the original array, and remove the dashes.

why does this hashtag regex extraction leave this in the front? "--- -"

2 Answers2