From: Joel VanderWerf <vjoel@...>
Date: 2008-07-07T07:00:57+09:00
Subject: Re: .include? for string

Chris Chris wrote:
> Hi,
> 
> I have an array a
> 
> => [["abc", "def", "ghi|ghi|kl"], ["jkl", "mno", "ghi|pqr"], ["stu",
> "vwx", "yz|abc"]]
> 
> Some strings contain the pipe character.
> 
> I want to delete all the arrows that do NOT contain a certain string.
> 
> I tried this:
> 
> a.delete_if { |x| !x.include? "ghi|ghi" }
> 
> => []
> 
> Of course, the array I need would be
> => [["abc", "def", "ghi|ghi|kl"]]

Enumerable#grep can be helpful here.

a = [["abc", "def", "ghi|ghi|kl"], ["jkl", "mno", "ghi|pqr"], ["stu",
"vwx", "yz|abc"]]

a.delete_if { |x| x.grep(/ghi\|ghi/).empty? }

p a # ==> [["abc", "def", "ghi|ghi|kl"]]

Note that the '|' char needs to be escaped in a regex.

Another option:

a.delete_if { |x| x.all? { |s| not s.include? "ghi|ghi" }}

Closer to the way you phrased the problem, but IMO a little less rubyesque.

-- 
       vjoel : Joel VanderWerf : path berkeley edu : 510 665 3407