Ruby in html.erb files

rubyonrails-talk
1

I have just started learning Rails and Ruby. I have succeeded in building an application so far. However, recently I tried embedding some ruby code in one of my html.erb files with the intention of further formatting the string that was being output. The original string was a set of lines with tab-delimited fields. So, I wanted to put it in pretty print HTML. For this, i used some string functions such as String.lines. When I try to view the said page, I get the following error:

undefined method `lines' for #<String:0x240d448>

The line of code where the error appears is:

@longshortgene.parsed_blast_report.lines { |line| print @line }

And if I insert a require 'String' in the beginning of the file, it still gives me the following error:

no such file to load -- String

I am completely new to Ruby, although I am learning the language parallel with Rails.

Can somebody please help me understand this problem, or point me to a relevant resource?

Thanks!

2

undefined method `lines' for #<String:0x240d448>

The line of code where the error appears is:

@longshortgene.parsed_blast_report.lines { |line| print @line }

What is @longshortgene.parsed_blast_report ? Did you mean each_line ? Also the variable you're using inside the block should be line, not @line (it's got to match what is in between the | |) You should also parse the result through h or you may output invalid html

Fred

3

Thanks, Fred. @longshortgene.parsed_blast_report is a string, which is a set of lines, each line consisting of tab-delimited fields. When I print @longshortgene.parsed_blast_report, it prints correctly. It is only when I try to parse it that I get the "undefined method" error for the method "lines". Do I need to create a new String object first using @longshortgene.parsed_blast_report and then use the method lines on it? I am going to try that next.

I corrected '@line' to 'line' and the error still persists.

Thanks!

4

I just checked this. There is in fact a method lines mentioned in the Ruby API docs for string. But if you list the methods of a string, it's missing.

that's from the docs:

str.lines(separator=$/) => anEnumerator str.lines(separator=$/) {|substr| block } => str

Returns an enumerator that gives each line in the string. If a block is given, it iterates over each line in the string.

"foo\nbar\n".lines.to_a #=> ["foo\n", "bar\n"] "foo\nb ar".lines.sort #=> ["b ar", "foo\n"]

So I see, what you want to do, but I don't know, what happened to this method. Maybe you can use one of te other string functions like split

5

Thanks, Fred. @longshortgene.parsed_blast_report is a string, which is a set of lines, each line consisting of tab-delimited fields. When I print @longshortgene.parsed_blast_report, it prints correctly. It is only when I try to parse it that I get the "undefined method" error for the method "lines". Do I need to create a new String object first using @longshortgene.parsed_blast_report and then use the method lines on it? I am going to try that next.

String doesn't have a lines method before ruby 1.8.7.

Fred

6

OK, now that makes sense for the error to show up then. Let me try other methods such as split. Thank you, Fred and Thorsten, for your help.

7

OK, here is the exact Ruby code I use now.

Line1: <%= @longshortgene.parsed_blast_report %> Line2: <% @longshortgene.parsed_blast_report.split(/\n/).each do | field> %> Line3: <%= field %> Line4: <% end %>

It works! Thanks again!