CODEWITHSUNDEEP
ruby-on-railsregexstring
Adam Templeton
Adam Templeton

Reputation: 4617

Setting string equal to match found by Rails regex

I'm trying to pull the user_id from a foursquare URL, like this one:

 https://foursquare.com/user/99999999

The following regex pulls exactly what I need (a series of numbers that terminate with the end of the line):

\d+$

However, I'm not sure how to set a string equal to the matched characters. I'm aware of sub and gsub, but those methods substitute a matched string for something else.

I'm looking for a way to specifically pull the section of a string that matches my regex (if it exists)

Upvotes: 4

Views: 10565

Answers (2)

Unixmonkey
Unixmonkey

Reputation: 18784

I like to use the return of match():

Anything wrapped in a capture () in the regex, gets assigned to the match result array

"https://foursquare.com/user/99999999".match(/(\d+)\z/)[1] #=> "99999999"

Upvotes: 11

Lee Jarvis
Lee Jarvis

Reputation: 16241

>> "https://foursquare.com/user/99999999"[/(\d+)\z/, 1]
=> "99999999"

>> "https://foursquare.com/user/99999999" =~ /(\d+)\z/
=> 28
>> $1
=> "99999999"

>> "https://foursquare.com/user/99999999".split('/').last
=> "99999999"

There are many ways. I personally like String#[] though

Upvotes: 5

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