From: Robert Klemme <shortcutter@...>
Date: 2011-04-04T18:13:15+09:00
Subject: Re: Using grep on subarrays - help!

On Sun, Apr 3, 2011 at 4:44 PM, Adam Prescott <adam@aprescott.com> wrote:
> 2011/4/3 Jesús Gabriel y Galán <jgabrielygalan@gmail.com>
>
>> result = []
>> test.each {|x| result << x unless x.grep(/one/).empty?}
>> result
>>
>
> More to-the-point:
>
> test.reject { |x| x.grep(/one/).empty? }

It seems we may want to match at the first position only, so I'd
rather do one of those

irb(main):003:0> test.select {|a,b| /one/ =~ a}
=> [["one", "vol1"], ["one", "vol2"]]
irb(main):004:0> test.select {|a,b| a == "one"}
=> [["one", "vol1"], ["one", "vol2"]]

If we are only interested in the other bit

irb(main):005:0> test.select {|a,b| a == "one"}.map {|a,b| b}
=> ["vol1", "vol2"]

Or, with #inject for a change since we know the key when doing exact matches

irb(main):006:0> test.inject([]) {|r,(a,b)| a == "one" ? r << b : r}
=> ["vol1", "vol2"]

Kind regards

robert

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