From: dblack@...
Date: 2006-10-26T07:09:19+09:00
Subject: Re: Functional Equivalency

Hi --

On Thu, 26 Oct 2006, tom.mancino wrote:

>
> On Oct 25, 12:50 pm, Justin Collins <colli...@seattleu.edu> wrote:
>> Rick DeNatale wrote:
>>> On 10/25/06, dbl...@wobblini.net <dbl...@wobblini.net> wrote:
>>
>>>> Hi --
>>
>>>> On Wed, 25 Oct 2006, tom.mancinowrote:
>>
>>>>> This works for multiple keywords:
>>
>>>>> res = adwords.estimateKeywordList([AdWords::KeywordRequest.new(nil,
>>>>> 1000000, false, 'test', 'Broad'), AdWords::KeywordRequest.new(nil,
>>>>> 1000000, false, 'student', 'Broad')])
>>
>>>>> This doesn't:
>>
>>>>> keywords = ['test','student']
>>>>> res = adwords.estimateKeywordList([keywords.map! {|x|
>>>>> AdWords::KeywordRequest.new(nil, 1000000, false, x, 'Broad')} ])
>>
>>>>> Aren't these statements functionaly equivilant, or have I missed
>>>>> something (probably!).....this may be an api problem as well.
>>
>>>> map! returns an array -- so in the second example, you've got an array
>>>> inside an array.
>>
>>> I don't think so. They should be equivalent.  Here's a simplification
>>> of the OPs use case, with a dummy KeywordRequest class and JUST the
>>> expression for the argument:
>>
>>> rick@frodo:/public/rubyscripts$ cat kwl.rb
>>> class KeywordRequest
>>>  def initialize(kwd)
>>>    @kwd = kwd
>>>  end
>>
>>>  def inspect
>>>    "KWR(#{@kwd})"
>>>  end
>>
>>> end
>>
>>> puts "With array literal"
>>> p [KeywordRequest.new('test'), KeywordRequest.new('student')]
>>
>>> keywords = ['test', 'student']
>>> puts "With map"
>>> puts "result=#{keywords.map {|x| KeywordRequest.new(x)}.inspect}"
>>> puts "keywords=#{keywords.inspect}"
>>> puts "with map!"
>>> puts "result=#{keywords.map! {|x| KeywordRequest.new(x)}.inspect}"
>>> puts "keywords=#{keywords.inspect}"
>>
>>> rick@frodo:/public/rubyscripts$ ruby kwl.rb
>>> With array literal
>>> [KWR(test), KWR(student)]
>>> With map
>>> result=[KWR(test), KWR(student)]
>>> keywords=["test", "student"]
>>> with map!
>>> result=[KWR(test), KWR(student)]
>>> keywords=[KWR(test), KWR(student)]
>>
>>> Both forms return a single level array of KeywordRequests.
>>
>>> It is probably better to use :map instead of :map! unless he WANTS to
>>> clobber the array of keywords.The point wasn't that map and map! are different - it's that the OP
>> takes the result from map! and puts it inside an array (note the square
>> brackets):
>>
>> res = adwords.estimateKeywordList([keywords.map! {|x| AdWords::KeywordRequest.new(nil, 1000000, false, x, 'Broad')} ])
>>
>> Which makes it an array within an array.
>>
>> With the first form, it's a flat array:
>>
>> res = adwords.estimateKeywordList([AdWords::KeywordRequest.new(nil, 1000000, false, 'test', 'Broad'), AdWords::KeywordRequest.new(nil, 1000000, false, 'student', 'Broad')])
>>
>> The difference is probably why the second form is failing.
>>
>> -Justin
> Justin,
>
>  I believe you must be correct, as it does produce different results.
> Any idea on how you would build a flat array that can take a variable
> in this situation?

I'm not sure what you mean by 'take a variable', but try just using
map (or map!) without wrapping it in ann array:

   res = adwords.estimateKeywordList(keywords.map! {|x| AdWords::KeywordRequest.new(nil, 1000000, false, x, 'Broad')})

(Note lack of square brackets.)


David

-- 
                   David A. Black | dblack@wobblini.net
Author of "Ruby for Rails"   [1] | Ruby/Rails training & consultancy [3]
DABlog (DAB's Weblog)        [2] | Co-director, Ruby Central, Inc.   [4]
[1] http://www.manning.com/black | [3] http://www.rubypowerandlight.com
[2] http://dablog.rubypal.com    | [4] http://www.rubycentral.org