Processing Array and returning boolean value

Question

I'm wondering, what would be the easiest way to check if all the elements of Array conform to certain criteria and return boolean? Is there maybe a pattern in Ruby to call method on collection and then return boolean value? Standard Enumerable methods return either Array or nil, so I'm not sure where to look.I've wrote an example that works using grep, but I feel that if could be skipped with more idiomatic code:

 def all_matched_by_regex?(regex)

     array_collection = ['test', 'test12', '12test']
     matched = array_collection.grep(regex)
     if matched.length == array_collection.length
        return true
     end
     return false
    end

Yes, that's it; one should be aware, though, about all? behaviour with empty collections (it returns true in such cases). I'd suggest checking any? as well, just reversing the pattern to check against. — raina77ow
– raina77ow, Commented Aug 11, 2013 at 20:32
That's it, yes! Not sure really how I managed to skip any/all.Thanks. — Zed
– Zed, Commented Aug 11, 2013 at 20:36

Antimony · Accepted Answer · 2013-08-11 20:47:24Z

4

Did you try Enumerable.all? {block} ? It seems like exactly what you're looking for.

Edit:

My Ruby is a bit rusty, but here's an example of how to use it

  regex = /test/
=> /test/
   array_collection = ['test', 'test12', '12test']
=> ["test", "test12", "12test"]
   array_collection.all? {|obj| regex =~ obj}
=> true

edited Aug 11, 2013 at 20:47

answered Aug 11, 2013 at 20:30

Antimony

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3 Comments

John Dvorak Over a year ago

I'm pretty sure that this counts as a link-only answer + a comment. Please note link-only answers are not welcome here.

Antimony Over a year ago

@Jan there's a standard library function that does exactly what was asked. What else is there to say?

John Dvorak Over a year ago

a code example would be nice. A code sample targeted at OP's situation - even better.

Arup Rakshit · Accepted Answer · 2013-08-11 20:37:41Z

0

You can change:

 if matched.length == array_collection.length
        return true
     end
     return false

with simply returning:

matched.length == array_collection.length

Like this:

def all_matched_by_regex?(regex)    
   array_collection = ['test', 'test12', '12test']
   matched = array_collection.grep(regex)
   matched.length == array_collection.length
end

edited Aug 11, 2013 at 20:37

Arup Rakshit

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answered Aug 11, 2013 at 20:31

Nir Alfasi

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