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Steve Odom

2006-May-02 15:12 UTC

[Rails] ordering after a inject

Hi,

My results are getting out of order after I do the following command:

count = result.inject({}) { |hsh, row| hsh[row[''name'']] =
row[''count''].to_i;
hsh }

Why?

Here are more specifics:

My complete method is this (based off of acts_as_taggable code - not''
DHHs,
but the original one):

def self.sql_to_count_plays(lookback)
        sql = ["SELECT t.name as name, COUNT(*) as count
                FROM histories h, tags t
                WHERE h.tag_id = t.id
                AND created_on > ?
                GROUP BY tag_id
                ORDER BY name", lookback]
        result = find_by_sql(sql)
        count = result.inject({}) { |hsh, row|
hsh[row[''name'']] row[''count''].to_i; hsh }
        count
end

The "result" is in the proper alpha order:
=> [#<Tag:0x3606ab0
@attributes={"name"=>"baseball",
"count"=>"2"}>,
#<Tag:0x360
6a68 @attributes={"name"=>"name",
"count"=>"29"}>, #<Tag:0x3606900
@attributes={
"name"=>"new", "count"=>"3"}>,
#<Tag:0x36065b8 @attributes={"name"=>"new
test fo
r tags", "count"=>"4"}>, #<Tag:0x3606210
@attributes={"name"=>"serial",
"count">"4"}>, #<Tag:0x3605fd0
@attributes={"name"=>"test",
"count"=>"1"}>]

but once it is processed through the result.inject function it gets out of
alpha order:
=> {"new"=>3, "name"=>29, "new test for
tags"=>4, "serial"=>4, "test"=>1, "
baseball"=>2}

I can''t figure out why or how to correct it. I don''t have the
latest pickaxe
book which documents the inject function and can''t find much
documentation
on it on the web. I could turn it into an sorted array using "count
count.sort_by { |r| r.name }", but I don''t want it in an array. In
need it
in a hash.

Any ideas?

Kind regards,

Steve Odom
http://www.smarkets.net
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Gregory Seidman

2006-May-02 16:13 UTC

head link

[Rails] ordering after a inject

On Tue, May 02, 2006 at 10:12:11AM -0500, Steve Odom wrote:
} My results are getting out of order after I do the following command:
} 
} count = result.inject({}) { |hsh, row| hsh[row[''name'']] =
row[''count''].to_i;
} hsh }
} 
} Why?
[...]
} but once it is processed through the result.inject function it gets out of
} alpha order:
} => {"new"=>3, "name"=>29, "new test for
tags"=>4, "serial"=>4, "test"=>1, "
} baseball"=>2}
} 
} I can''t figure out why or how to correct it. I don''t have
the latest pickaxe
} book which documents the inject function and can''t find much
documentation
} on it on the web. I could turn it into an sorted array using "count }
count.sort_by { |r| r.name }", but I don''t want it in an array. In
need it
} in a hash.

Hashes are unordered containers. They do not maintain order. That is not
what they do.

} Any ideas?
} Kind regards,
} Steve Odom
--Greg

Steve Odom

2006-May-02 16:31 UTC

head link

[Rails] ordering after a inject

Aww. Thanks.

On 5/2/06, Gregory Seidman <gsslist+ror@anthropohedron.net>
wrote:>
> On Tue, May 02, 2006 at 10:12:11AM -0500, Steve Odom wrote:
> } My results are getting out of order after I do the following command:
> }
> } count = result.inject({}) { |hsh, row| hsh[row[''name'']]
> row[''count''].to_i;
> } hsh }
> }
> } Why?
> [...]
> } but once it is processed through the result.inject function it gets out
> of
> } alpha order:
> } => {"new"=>3, "name"=>29, "new test for
tags"=>4, "serial"=>4,
> "test"=>1, "
> } baseball"=>2}
> }
> } I can''t figure out why or how to correct it. I don''t
have the latest
> pickaxe
> } book which documents the inject function and can''t find much
> documentation
> } on it on the web. I could turn it into an sorted array using "count
> } count.sort_by { |r| r.name }", but I don''t want it in an
array. In need
> it
> } in a hash.
>
> Hashes are unordered containers. They do not maintain order. That is not
> what they do.
>
> } Any ideas?
> } Kind regards,
> } Steve Odom
> --Greg
>
> _______________________________________________
> Rails mailing list
> Rails@lists.rubyonrails.org
> http://lists.rubyonrails.org/mailman/listinfo/rails
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Jean-François

2006-May-02 23:49 UTC

head link

[Rails] ordering after a inject

Hello Steve,
> My results are getting out of order after I do the following command:
>
> count = result.inject({}) { |hsh, row| hsh[row[''name'']] =
row[''count''].to_i;
> hsh }
>
> Why?
>
> Here are more specifics:
>
>  My complete method is this (based off of acts_as_taggable code
> - not'' DHHs, but the original one):
>
> def self.sql_to_count_plays(lookback)
>         # ...
>         result = find_by_sql(sql)
>         count = result.inject({}) { |hsh, row|
hsh[row[''name'']] > row[''count''].to_i; hsh
}
>         count
> end
>
> The "result" is in the proper alpha order: [...]
>
> but once it is processed through the result.inject function it gets out of
> alpha order:
> => {"new"=>3, "name"=>29, "new test for
tags"=>4, "serial"=>4, "test"=>1, "
> baseball"=>2}
>
> I can''t figure out why or how to correct it. I don''t have
the latest pickaxe
> book which documents the inject function and can''t find much
documentation
> on it on the web. I could turn it into an sorted array using "count
> count.sort_by { |r| r.name }", but I don''t want it in an
array. In need it
> in a hash.
Gregory has answered you but here some additional information :

1/ if you have my_hash = MyModel.sql_to_count_plays(lookback)

you can convert into a "sort of ordered hash like object", in fact an
array of nested pairs, with Hash#sort method :

irb(main):001:0> my_hash={"new"=>3, "name"=>29,
"new test for
tags"=>4, "serial"=>4, "test"=>1,
"baseball"=>2}.sort
=> [["baseball", 2], ["name", 29], ["new", 3],
["new test for tags",
4], ["serial", 4], ["test", 1]]

then you can iterate on each pair :
> my_hash.each { |p| puts "#{p.first}(#{p.last})" }baseball(2)
name(29)
new(3)
new test for tags(4)
serial(4)
test(1)

2/ There is an OrderedHash class in Rails.
In 1.0, it was class OrderedOptions, then it has been refactored a little
bit OrderedOptions < OrderedHash in 1.1.
In trunk, it''s called (very recently) ActiveSupport::OrderedHash.

If you look in : activesupport/lib/active_support/ordered_options.rb
you will see that''s basically a "nested pairs in array"
structure
encapsulated in an OrderedHash instance.

HTH,

    -- Jean-Fran?ois.


--
? la renverse.

Steve Odom

2006-May-03 00:31 UTC

head link

[Rails] ordering after a inject

Thanks for this, Jean-Francois. This is helpful. I''ll check it out.

Steve

On 5/2/06, Jean-Fran?ois <jf.web3@gmail.com>
wrote:>
> Hello Steve,
>
> > My results are getting out of order after I do the following command:
> >
> > count = result.inject({}) { |hsh, row|
hsh[row[''name'']] > row[''count''].to_i;
> > hsh }
> >
> > Why?
> >
> > Here are more specifics:
> >
> >  My complete method is this (based off of acts_as_taggable code
> > - not'' DHHs, but the original one):
> >
> > def self.sql_to_count_plays(lookback)
> >         # ...
> >         result = find_by_sql(sql)
> >         count = result.inject({}) { |hsh, row|
hsh[row[''name'']] > >
row[''count''].to_i; hsh }
> >         count
> > end
> >
> > The "result" is in the proper alpha order: [...]
> >
> > but once it is processed through the result.inject function it gets
out
> of
> > alpha order:
> > => {"new"=>3, "name"=>29, "new test
for tags"=>4, "serial"=>4,
> "test"=>1, "
> > baseball"=>2}
> >
> > I can''t figure out why or how to correct it. I don''t
have the latest
> pickaxe
> > book which documents the inject function and can''t find much
> documentation
> > on it on the web. I could turn it into an sorted array using
"count > > count.sort_by { |r| r.name }", but I don''t
want it in an array. In need
> it
> > in a hash.
>
> Gregory has answered you but here some additional information :
>
> 1/ if you have my_hash = MyModel.sql_to_count_plays(lookback)
>
> you can convert into a "sort of ordered hash like object", in
fact an
> array of nested pairs, with Hash#sort method :
>
> irb(main):001:0> my_hash={"new"=>3,
"name"=>29, "new test for
> tags"=>4, "serial"=>4, "test"=>1,
"baseball"=>2}.sort
> => [["baseball", 2], ["name", 29], ["new",
3], ["new test for tags",
> 4], ["serial", 4], ["test", 1]]
>
> then you can iterate on each pair :
>
> > my_hash.each { |p| puts "#{p.first}(#{p.last})" }
> baseball(2)
> name(29)
> new(3)
> new test for tags(4)
> serial(4)
> test(1)
>
> 2/ There is an OrderedHash class in Rails.
> In 1.0, it was class OrderedOptions, then it has been refactored a little
> bit OrderedOptions < OrderedHash in 1.1.
> In trunk, it''s called (very recently) ActiveSupport::OrderedHash.
>
> If you look in : activesupport/lib/active_support/ordered_options.rb
> you will see that''s basically a "nested pairs in array"
structure
> encapsulated in an OrderedHash instance.
>
> HTH,
>
>     -- Jean-Fran?ois.
>
>
> --
> ? la renverse.
>
> _______________________________________________
> Rails mailing list
> Rails@lists.rubyonrails.org
> http://lists.rubyonrails.org/mailman/listinfo/rails
>
>
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