Ruby - strings operation

Question

I have this simple helper:

def printe_result(data)
  a_var = ('<a href="http://'+data.a_value+'>A</a>' unless (data.a_value.nil? || data.a_value.empty?))
  b_var = ('<a href="http://'+data.b_value+'>B</a>' unless (data.b_value.nil? || data.b_value.empty?))
  c_var = ('<a href="http://'+data.c_value+'>C</a>' unless (data.c_value.nil? || data.c_value.empty?))

  return ...
end

a_value, b_value, c_value I am taking from database. If the values are strings, I want to save them into the respective variable and then all variables return as one string with the values separated by comma, for example:

"<a href=http://a>A</a>, <a href=http://b>B</a>, <a href=http://c>C</a>"

How can I merge the variables only if they exist?

Answer 1

def printe_result(data)
  { 'A' => data.a_value, 'B' => data.b_value, 'C' => data.c_value }.map do |name, val|
    "<a href='http://#{val}'>#{name}</a>" unless val.blank?
  end.compact.join(',')
end

Answer 2

Something like

 [[a_value,'A'],[b_value,'B'],[c_value,'C']].select {|(value, label)| !value.blank?}.
    map {|(value, label)| %q[<a href="http://#{value}">#{label}</a>]}.join(',')

Ought to do the trick: use select to eliminate pairs with blank labels, map to turn the label into the desired text and join to join the strings together.

Answer 3

I hope i get your question right - you can use the defined?(variable_name) method to check if a variable has been defined.

I hope this helps!