From: "David A. Black" <dblack@...>
Date: 2008-08-20T21:56:29+09:00
Subject: Re: array of hashes - need to iterate and calulate stats but how

Hi --

On Wed, 20 Aug 2008, Lex Williams wrote:

> David A. Black wrote:
>> Hi --
>>
>> On Wed, 20 Aug 2008, Lex Williams wrote:
>>
>>>        end
>>>    end
>>> end
>>>
>>> and then you would have a statistic_hash containing as key a product
>>> name , and as value , the number of units sold. I'm not sure about how
>>> to calculate the statistics .
>>
>> You can use a hash with a default value to make all that hash testing
>> easier:
>>
>>    statistic_hash = Hash.new(0)
>>    array.each do |hash|
>>      next unless hash[:did_it_sell]
>>      statistic_hash[hash[:title]] += 1
>>    end
>>
>>
>> David
>
> you could use select on the array , and lose those if's . something like
> this :
>
> array.select { |hash| hash[:did_it_sell] }.each do |hash|
>  statistic_hash[hash[:title]] += 1
> end

To answer my own question: I guess you do mean the 'unless'. I
deliberately didn't use select just to save the creation of an
intermediate object, and because I think that the 'next unless' line
is nice and expressive.


David

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