From: "David A. Black" <dblack@...>
Date: 2008-07-07T07:08:34+09:00
Subject: Re: .include? for string

Hi --

On Mon, 7 Jul 2008, Joel VanderWerf wrote:

> 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.

I kind of like this hybrid:

>> def a.delete_unless(&block); replace select(&block); end
=> nil
>> a.delete_unless {|ary| ary.include? {|string| string.include?("ghi|ghi") }}
=> [["abc", "def", "ghi|ghi|kl"]]


David

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