From: Robert Klemme <shortcutter@...>
Date: 2008-08-20T01:26:40+09:00
Subject: Re: Find element in array of hashes

On 19.08.2008 18:13, Adgar Marks wrote:
> Dear all,
> 
> i am trying to find my way in Ruby, but i am just a bignner. Here is my
> problem:
> 
> I have two array of hashes:
> 
> _DownloadData << { :FileName =>  splitLine[0]      ,
>                    :Size     =>  splitLine[4].to_i  }
> 
> _FilesData << { :FileName =>  splitLine[8]      ,
>                 :Year     =>  year              ,
>                 :Month    =>  month             ,
>                 :Day      =>  day               ,
>                 :Suffix   =>  suffix            ,
>                 :JDay     =>  jday              ,
>                 :Size     =>  splitLine[4].to_i  }

I assume _DownloadData and _FilesData are of type Array.

> I would like to know if FileName from _FileesData is in _DownloadData
> and later or if the two files have the same size.
> 
> I tried to write it like this:
> if _DownloadData[:FileName].include?( _FilesData[:FileName] )
> 
> and i already got an error.

Well, if they are arrays you rather need something like this:

_DownloadData.each |dl|
   x = _FilesData.find {|fl| fl[:FileName] == dl[:FileName]}
   if x
     # found
   end
end

But note that this is inefficient if you have multiple entries in both 
arrays.  In that case building a hash with the file name as key could 
speed up things considerably.

Btw, conventionally variables in Ruby have all lowercase names with 
underscores and no leading underscore.

Kind regards

	robert