Re: rails 2D array access in Helper method

Tamara Temple
Mon, 04 Nov 2013 09:19:15 -0000

On Nov 3, 2013, at 3:35 PM, Tamara Temple
<tamouse.lists-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:

>
> On Nov 1, 2013, at 9:20 AM, leo nike
<lists-fsXkhYbjdPsEEoCn2XhGlw@public.gmane.org> wrote:
>
>> Hi, I Want to simply print out 2d array elements. Method is located in
>> Helper module. Calling helper method from jQuery. At the moment
I''m not
>> getting output (=> 0..3) I tried to do iterate through array via
.each()
>> method, but it would just print en entire array, however i want to
>> access each element and convert it either to string or integer. can
>> someone point me to possible solution? thanks!
>>
>>      #app/helpers/controller_helper.rb
>>          def get_array
>>             database = SQLite3::Database.open("test.db")
>>             result = database.execute("select * from table1")
>>             print_array(result)
>>          end
>>
>>          def print_array(array)
>>            for i in 0..array.length
>>                 puts array[i][i]
>>            end
>>          end
>>
>>     -------------------------------------------------------------------
>>    #app/views/controller/file.js.erb
>>
if($(''.check_box1'').is('':checked'')){
>>           $("#div2").html("<%= get_array%>")
>>      }
>>
>> --
>> Posted via http://www.ruby-forum.com/.
>
> You don’t want to use puts in there. You want to return the value so it
gets evaluated in the erb code. puts returns nil, which means you get nothing
inside the html element.
>
> I’m not exactly sure from that method what you want inside div2 either.
>
> Here’s what I’d suggest:
>
> def get_array()
>  # sqlite stuff as you have it
>  format_table(result)
> end
>
> def format_table(data)
> out = " \n"
>  out += data.map do |row|
>    format_row(row)
>  end.join("\n")
> out += "\n \n"
> end
>
> def format_row(row)
> out = " "
>  out += row.map do |cell|
>    format_cell(cell)
>  end.join
> out += " "
> end
>
> def format_cell(cell)
> " #{cell} "
> end
>
> This will output html code, which seems like what you’d want at that point.

then i decided it was too ''wet'', and refactored:

def wrap(s, tag, attr={}, &b)
  s = [s] unless s.is_a? Array
  attr = attr.empty? ? '''' : " #{attr.map{|k,v|
"#{k}=''#{v}''"}.join(" ")}"
  out = "<#{tag}#{attr}>"
  out += s.inject("") {|m,o| m+="#{block_given? ? (yield o) :
o}"}
  out += "</#{tag}>"
end


def format_table(data)
  wrap(data,"table",border: 1) do |row|
    wrap(row,"tr") do |cell|
      wrap(cell,"td")
    end
  end
end

data=[[1,2,3,4],[5,6,7,8]]

formate_table(data) # => "<table
border=''1''> 1 2 3 4 5 6 7 8 "

(https://gist.github.com/tamouse/7300078 )

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