Question

I am parsing a tsv file and loading it into MySQL. I got this to work then found there are back slashes in the tsv file that are being interpreted as line breaks. I would like to remove the \ from all fields before the data is sent to the database. This is a shortened example, there are 300 columns in the file and many of them will be blank.

begin              
  CSV.foreach(file, :col_sep => "\t") do |row|
      row.map!{ |e| e.gsub(/\\/, '')} 
      d = Datafeed.new
      d.id = row[0]
      d.description = row[1]
      d.save!
  end
end

When I run this example, I get an error: undefined method `gsub’ for nil:NilClass. I think this error is being generated by blanks in the file. However, when I try adding

row.map!{ |e| unless e.blank e.gsub(/\\/, '') } 

it will not execute and I get an error for an unexpected }.

Is this the right direction to eliminate the back slashes? What is the best approach?

Thanks

Answer 1

The unless statement should follow the other code. That’s what is causing the second error. Try this:

row.map!{ |e| e.gsub(/\\/, '') unless e.blank? }

Note: That code will turn "" into nil which may or may not be what you expect.

Your approach seems reasonable.

Edit:

To retain the blanks, you can do the following:

row.map!{ |e| e.blank? ? '' : e.gsub(/\\/, '') }

or if that’s a bit too much for one line for you, this:

row.map! do |e|
  if e.blank?
    ''
  else
    e.gsub(/\\/, '')
  end
end