rails 2D array access in Helper method

rubyonrails-talk
1

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

2

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 = "<table>\n"   out += data.map do |row|     format_row(row)   end.join("\n")   out += "\n</table>\n" end

def format_row(row)   out = "<tr>"   out += row.map do |cell|     format_cell(cell)   end.join   out += "</tr>" end

def format_cell(cell)   "<td>#{cell}</td>" end

This will output html code, which seems like what you’d want at that point.

3

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'><tr><td>1</td><td>2</td><td>3</td><td>4</td></tr><tr><td>5</td><td>6</td><td>7</td><td>8</td></tr></table>"

(Formatting a 2D array as an HTML table · GitHub )

4

Great! I didnt even think about implementation like that, that's awesome. thanks a lot! can I contact you, in case something doesnt work here?

5

Just reply on list, there are some truly awesome people here, most definitely not including me.

6

Listening to one of Ruby Tapas made me shake my head with pain. This:

   s = [s] unless s.is_a? Array

should be this:

  s = Array.new(s)

7

Hi, once again thanks for you code contribution, that helped me to see problem from a different perspective a little bit. I liked both of your code snippets, and 1st one in particular (since i actually understand it)

There is only one issue though, if I try to run code below on trough jQuery (when the checkbox is checked) it wouldnt really execute anything. That's what I had problem before, and I know the problem is not with jQuery method. I cant easily modify code to $("#div2").html("<%= 'hello'%>") and it would print 'hello' in that div. So, there is something that jQuery doesnt see in iether get_array or format_table method. I've tried to merge all the 4 methods into one and run it as one method, but it still wouldnt work. Would you please check it one again, and let me know what could be changed?

And yes, I just want to output the result of parsed array into html code. I dont really care how, it's just I know only Jquery .html() method and it seems relatively simple.

Thank you very much

def get_array()   # sqlite stuff as you have it   format_table(result) end

def format_table(data)   out = "<table>\n"   out += data.map do |row|     format_row(row)   end.join("\n")   out += "\n</table>\n" end

def format_row(row)   out = "<tr>"   out += row.map do |cell|     format_cell(cell)   end.join   out += "</tr>" end

def format_cell(cell)   "<td>#{cell}</td>" end