Question

I’ve got a group of strings and I’m trying to remove everything after and including the last occurance of a regexp match.

Sample Data
23401BK221
23430-BZ-221
1004113-BK-3
14989r-113
30402113

I am attempting to do this with

extensions_to_remove="BK|BZ|113"
sample_data = sample_data.split(/.*(#{extensions_to_remove}$1)/)

I was hoping that I would get an array where I could just take the first entry, but unfortunately, I’m getting

["","BK", "-221"]
["","BZ","-221"]
["","BK", "-3"]
["","113"]
["", "113"]

What I’m hoping to get is

23401
23430
1004113
14989r
30402

So essentially remove everthing after the last match, and then if their is a trailing ‘-‘ I’m trying to remove that.

I figured if I got it into an array, I could take the first value, then strip the trailing ‘-‘, if it existed.

Any suggestions on what I’m doing wrong? Why I’m not getting the prefixes back?
Is there a better way to do this?

Answer 1

Try this regular expression:

(\w+).*(BK|BZ|113)

Code:

data = ["23401BK221", "23430-BZ-221", "1004113-BK-3", "14989r-113", "30402113"]
data.each {|d| p d.split(/(\w+).*(BK|BZ|113)/)[1]}

Output:

gazler@gazler-desktop:~$ ruby -v
ruby 1.9.2p180 (2011-02-18 revision 30909) [x86_64-linux]
gazler@gazler-desktop:~$ irb
ruby-1.9.2-p180 :001 > data = ["23401BK221", "23430-BZ-221", "1004113-BK-3", "14989r-113", "30402113"]
 => ["23401BK221", "23430-BZ-221", "1004113-BK-3", "14989r-113", "30402113"] 
ruby-1.9.2-p180 :002 > data.each {|d| p d.split(/(\w+).*(BK|BZ|113)/)[1]}
"23401"
"23430"
"1004113"
"14989r"
"30402"

Rubular link: http://rubular.com/r/kKrseNE7ZX