Regexp#match returns nil if it doesn't match anything. On the first  
run through your each statement, s is "foo", which doesn't match  
against your regex. That means m is nil, and so you get an error when  
trying to grab m[0].

On 1/07/2006, at 12:58 PM, Volkan Civelek wrote:

>  Hi,
>  I have a question...
> 
>  Why the below snippet,
> 
>  ["foo","bar","baz"].each do |s|
>      m = /^ba(.*?)$/.match(s)
>      puts m[0]
>  end
> 
>   gives the following error?
> 
>  test.rb:8: undefined method `[]' for nil:NilClass (NoMethodError)
> 
>  Regards,
>  Volkan
>