Finding a regex match from an array of regexes

Question

def match_line regex
    @line.match(regex) if !regex.is_a?(Array)
    regex.each {|rgx| 
        results = @line.match(rgx) 
        return results if !results.nil? 
    }
    return nil
end

This looks like something that could be done in a one line idiomatic way, and I'm just not seeing how.

Your question isn't clear. Do you want to see if one of the regex patterns in the array matches something? Or, do you want to find out which of the regex patterns matched? — the Tin Man
– the Tin Man, Commented Apr 16, 2011 at 19:23
You meant to put return before the second line, I suppose. — sawa
– sawa, Commented Apr 16, 2011 at 19:46

Rein Henrichs · Accepted Answer · 2011-04-16 19:10:55Z

5

[*regex].map{ |re| @line.match re }.compact.first

or

Array(regex).map{ |re| @line.match re }.compact.first

answered Apr 16, 2011 at 19:10

Rein Henrichs

15.6k1 gold badge47 silver badges55 bronze badges

Sign up to request clarification or add additional context in comments.

3 Comments

Jeremy Smith Over a year ago

Thank you, that is great. Does the Array() turn a variable into an array if it isn't already one? Also, I assume all of the regexes are matched and there isn't a way to jump out after the first match?

Jeremy Smith Over a year ago

nm on Array().. that's a very useful function.

Rein Henrichs Over a year ago

That's correct, it will iterate over all regexes in regex, but assuming there are relatively few this won't be a big deal. You could do a custom each that short-circuits but I doubt the performance gain would be worth the loss in readability.

Mike Lewis · Accepted Answer · 2011-04-16 19:09:55Z

1

 [*regex].find{|r| @line.match(r)}
 return $~ #will return the last MatchedData returned, otherwise nil.

$~ will return the last MatchedData returned, otherwise nil.

answered Apr 16, 2011 at 19:09

Mike Lewis

64.3k20 gold badges144 silver badges111 bronze badges

2 Comments

Rein Henrichs Over a year ago

:( perlish magic global variables are unreadable, as indicated by your explaining comment.

Mike Lewis Over a year ago

Having a comment associated with that line seems like no issue to me, especially because it is literally one line that is in question.

DigitalRoss · Accepted Answer · 2011-04-16 19:43:58Z

0

def match_line regex
  [*regex].each { |r| return r if (r = @line.match r) }
end

answered Apr 16, 2011 at 19:43

DigitalRoss

147k25 gold badges255 silver badges336 bronze badges

Comments

sawa · Accepted Answer · 2011-04-16 19:52:07Z

0

It is a preferred, established practice to pass arguments in this case like

match_line(regex1, regex2, ...)

or

match_line(*array_of_regexes)

rather than

match_line([regex1, regex2, ...])

or

match_lines(array_of_regexes)

so your conditioning regarding array-ness is unnecessary.

def match_line *regex
  regex.detect{|r| @line =~ r}
  Regexp.last_match
end

answered Apr 16, 2011 at 19:52

sawa

169k51 gold badges287 silver badges398 bronze badges

Collectives™ on Stack Overflow

Finding a regex match from an array of regexes

4 Answers 4

3 Comments

2 Comments

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

4 Answers 4

3 Comments

2 Comments

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related