From: Rob Biedenharn <Rob@...>
Date: 2009-01-29T04:28:23+09:00
Subject: Re: "adding" two hashes

On Jan 28, 2009, at 2:07 PM, Bryson Smith wrote:

> Hi,
>
> I'm wondering if it is possible to "add" the values of two hashes
> together.  Suppose I had:
>
> hash1 = {:key_one=>100, :key_two=>200}
> hash2 = {:key_two=>300, :key_three=>400}
>
> I'd like to "add" the hashes together so that I get
>
> result => {:key_one=>100, :key_two=>500, :key_three=>400}
>
> Do I need to write my own function to parse through each hash's keys?
> Is there a built-in way to do this?
>
> Thanks!


irb> hash1 = {:key_one=>100, :key_two=>200}
=> {:key_two=>200, :key_one=>100}
irb> hash2 = {:key_two=>300, :key_three=>400}
=> {:key_two=>300, :key_three=>400}

irb> result = hash1.merge(hash2) {|key,val1,val2| val1+val2}
=> {:key_two=>500, :key_three=>400, :key_one=>100}

You only have to write the block that deals with the duplicates for  
'key'

-Rob

Rob Biedenharn		http://agileconsultingllc.com
Rob@AgileConsultingLLC.com