Extract using regex

Question

I'm new to Ruby, Regex and Stackoverflow. xD Here's my problem:

I want to use regex to extract phrases consisting of consecutive words with standard ASCII characters apart from the others in Vietnamese texts.

In another word, phrases with \w characters only, for example:

Mình rất thích con Sharp này (mặc dù chưa xài bao h nhưng chỉ nghe các pác nói mình đã thấy phê lòi mắt rồi). Các bạn cho mình hỏi 1 câu (các bạn đừng chê mình ngu nhé tội nghiệp mình) : cái máy này đem sang Anh dùng mạng Vodafone là dùng vô tư ah`? Nếu dùng được bên Anh mà không phải chọc ngoáy j thì mình mua một cái

Don't care about its meaning, what I want to achieve is an array of hashes containing the results with 2 pairs: value => the value of extracted phrases, starting_position => the position of the first character.

According to the example about, it should be like this: [{:value=>"con Sharp", :starting_position => 16}, {:value=>"bao h", :starting_position => blah blah}...]

This means that all words containing \W characters, such as "mình", "rất", "thích", etc. are rejected.

Trying above example with this regex on rubular.com for Ruby 1.9.2:

\b[\w|\s]+\b

I nearly got my desired phrases (except space-only ones), but it seems not working on my Ruby, which is also 1.9.2p290, using Win 7 64-bit.

Any ideas would be highly appreciated. Thank you beforehand.

score 1 · Accepted Answer · edited May 23 '17 at 10:08

1

According to rubular, it looks like \w matches all ascii letters and numbers (and underscored), but \b is working well for all Unicode letters. That is a little confusing.

What you want, however, are all sequences of ASCII words. This should match them:

/\b[a-z]+\b(?:\s+[a-z]+)*\b/i

Working example: http://www.rubular.com/r/1iewl7MpJe

A quick explanation:

\b[a-z]+\b - first ASCII word.
(?:\s+[a-z]+) - any number of spaces and words - at least one space and one letter each time.
\b - to assure the last word doesn't end in the middle of another word, like n in "con Sharp này".

I'm not sure about getting an hash, but you can get all MatchDatas, similar to:
How do I get the match data for all occurrences of a Ruby regular expression in a string?

s = "hello !@# world how a9e you"
r = /\b[a-z]+\b(?:\s+[a-z]+)*\b/i

matches = s.to_enum(:scan, r).map { Regexp.last_match }
           .map {|match| [match.to_s(), match.begin(0)]}
puts matches

Here's an example on ideone: http://ideone.com/YRZE5

edited May 23 '17 at 10:08

Community

1
1

answered Mar 30 '12 at 12:17

Kobi

135,331
41
252
292

Looks like `\b\w+\b(?:\s+\w+)*\b` would work as well. I'm not sure why I thought \w does match all Unicode letters... Anyway, I'll be checking some documentations. I can't really find it in http://www.ruby-doc.org/core-1.9.3/Regexp.html – Kobi Mar 30 '12 at 12:25
That's great! Thank you so much. By the way, how can I get result array as described above using Ruby? I tried **scan** and **match** but did not know how to deal with them? – Thiem Nguyen Mar 30 '12 at 12:48
@ThiemNguyen - Thanks! I've added an example for getting the data you need. I don't really know Ruby aside from answering Stack Overflow questions, so you can probably do better then me `:P` – Kobi Mar 30 '12 at 16:08
I managed to extract them using Ruby and your regex. Thanks in advance. xD – Thiem Nguyen Apr 01 '12 at 06:25

Extract using regex

1 Answers1