OT: How to make this code prettier?

Rails
1

This isn’t specific to Rails, but I would like to learn from the
experience of others.

How would you make this code prettier…

Docdesc = Struct.new(:document_category_id,
:document_number_prefix,
:primary_part_number,
:document_family_series,
:description,
:revision,
:release_status,
:originator,
:docdate)
…
row = some_array_of_strings_ints_and_floats()
dd = Docdesc.new
dd.document_category_id = c.id
dd.document_number_prefix = row[0].to_s unless row[0].nil?
dd.primary_part_number = row[1].to_s unless row[1].nil?
dd.document_family_series = row[2].to_s unless row[2].nil?
dd.description = row[3].to_s unless row[3].nil?
dd.revision = row[4].to_s unless row[4].nil?
dd.release_status = row[5].to_s unless row[5].nil?
dd.originator = row[6].to_s unless row[6].nil?
dd.docdate = row[7].to_s unless row[7].nil?

–wpd

2

Something = Struct.new(:one, :two, :three)

index = 0
for x in %w{ one= two= three= }
dd.send x, row[ index ]
index += 1
end

using hash, not struct should be even simpler…

Patrick D. wrote:

This isn’t specific to Rails, but I would like to learn from the
experience of others.

How would you make this code prettier…

Docdesc = Struct.new(:document_category_id,
:document_number_prefix,
:primary_part_number,
:document_family_series,
:description,
:revision,
:release_status,
:originator,
:docdate)
…
row = some_array_of_strings_ints_and_floats()
dd = Docdesc.new
dd.document_category_id = c.id
dd.document_number_prefix = row[0].to_s unless row[0].nil?
dd.primary_part_number = row[1].to_s unless row[1].nil?
dd.document_family_series = row[2].to_s unless row[2].nil?
dd.description = row[3].to_s unless row[3].nil?
dd.revision = row[4].to_s unless row[4].nil?
dd.release_status = row[5].to_s unless row[5].nil?
dd.originator = row[6].to_s unless row[6].nil?
dd.docdate = row[7].to_s unless row[7].nil?

–wpd

3

Something = Struct.new(:one, :two, :three)

index = 0
for x in %w{ one= two= three= }
dd.send x, row[ index ]
index += 1
end
Thanks for the suggestion. I thought (a very little bit) about
quoting the member names of the structure, but, where they are rather
long, I thought the %w{some_very_long_name, some_other_very_log_name,
etc…} looked a little unwieldy, and not any prettier than what I
started with, (especially when one has to remember to tack on the
equal sign at the end of each name).

Gently guiding this back onto the topic of Rails… later in my code,
I want to initialize an ActiveRecord object from my Struct element. I
tried this:

dbdoc = Document.new(doc.hash)

Where Document looks like:

class Document < ActiveRecord::Base
belongs_to :document_category
end

and doc is instance of my structure I defined previously. However,
when I try this, I get an exception:

…/activerecord-2.0.2/lib/active_record/base.rb:2110:in `dup’: can’t
dup Fixnum (TypeError)

So I am left with:

      dbdoc = Document.new
      dbdoc.document_category_id = doc.document_category_id
      dbdoc.document_number_prefix = doc.document_number_prefix
      dbdoc.primary_part_number = doc.primary_part_number
      dbdoc.document_family_series = doc.document_family_series
      dbdoc.description = doc.description
      dbdoc.revision = doc.revision
      dbdoc.release_status = doc.release_status
      dbdoc.originator = doc.originator
      dbdoc.docdate = doc.docdate

which, again, looks uglier than I think it should.

Any suggestions?

4

On Apr 14, 8:44 pm, “Patrick D.” [email protected] wrote:

      dbdoc.originator = doc.originator
      dbdoc.docdate = doc.docdate

which, again, looks uglier than I think it should.>
Well if you know that the column/field names will always match up you
can use the fact that struct mixes in enumerable, so for example you
can do
doc.each_pair do |name, value|
dbdoc.send(name.to_s + ‘=’, value)
end
You could also use that to build up a hash that you could give to
Document.new

Fred

5

which, again, looks uglier than I think it should.>
Well if you know that the column/field names will always match up you
I can (and have) make that to be the case

can use the fact that struct mixes in enumerable, so for example you
can do
doc.each_pair do |name, value|
dbdoc.send(name.to_s + ‘=’, value)
end
That’s clever. But is it more readable? If it is idiomatic Ruby,
then I would say “yes it is more readable”. Being rather new to Ruby
and not having read any production Ruby code, I don’t know if that’s
idiomatic or not.

You could also use that to build up a hash that you could give to
Document.new
That’s what I tried originally:

dbdoc = Document.new(doc.hash)

but that threw an exception:
…/activerecord-2.0.2/lib/active_record/base.rb:2110:in `dup’: can’t
dup Fixnum (TypeError)

–wpd

6

On Apr 14, 11:38 pm, “Patrick D.” [email protected] wrote:

That’s clever. But is it more readable? If it is idiomatic Ruby,
then I would say “yes it is more readable”. Being rather new to Ruby
and not having read any production Ruby code, I don’t know if that’s
idiomatic or not.
It’s either readable or not, make your own mind up about it :slight_smile: It
doesn’t make a lot of sense to have someone else tell you if something
is readable: if you find it readable then that should be good enough
for you. slightly cuter is doc.each_pair {|name, value|
dbdoc[name]=value} but it’s not quite the same things (since it just
writes the attribute rather than calling any custom accessor you may
have created)

dup Fixnum (TypeError)

That’s not what hash does. hash returns an integer (such that a.hash !
= b.hash => a != b) which is used when storing things like that in a
hash. If you want a hash you need to iterate over the struct and build
it typ.

Fred