From: Tim Hunter <TimHunter@...>
Date: 2008-01-04T09:52:38+09:00
Subject: Re: Finding if an array contains a data type

Sam Phoneix wrote:
> Say I wanted to see if an array contained a number or not. Would I use
> the match method?
> 
> E.g.
> 
> x=["a","b",2, "c"]
> 
> puts("This array contains numbers") if x.match(/\d/)
> 
> 
> 
> 
> 
> I'm a real beginner at ruby, so simple explanations for simple folk
> please. I appreciate your help.

Nice try, but match matches strings and you're wanting numbers.

Note that the Array class includes the Enumerable module, so all methods 
in Enumerable are available in Array. Enumerable has a method called 
"any?" that we can use. Here's what ri says about Enumerable#any?

$ ri Enumerable#any?
-------------------------------------------------------- Enumerable#any?
      enum.any? [{|obj| block } ]   => true or false
------------------------------------------------------------------------
      Passes each element of the collection to the given block. The
      method returns true if the block ever returns a value other than
      false or nil. If the block is not given, Ruby adds an implicit
      block of {|obj| obj} (that is any? will return true if at least
      one of the collection members is not false or nil.

         %w{ ant bear cat}.any? {|word| word.length >= 3}   #=> true
         %w{ ant bear cat}.any? {|word| word.length >= 4}   #=> true
         [ nil, true, 99 ].any?                             #=> true


So, here's how to use it:

irb(main):001:0> x=["a","b",2, "c"]
=> ["a", "b", 2, "c"]
irb(main):002:0> x.any? {|p| p.is_a? Numeric}
=> true



-- 
RMagick: http://rmagick.rubyforge.org/
RMagick 2: http://rmagick.rubyforge.org/rmagick2.html