Add array items to array in one line

Question

I am building a CSV object and I have a dynamic set of header items. I build this 'header' row as follows:

headers = ["name", "email"]
questions.each do |q|
  headers << q
end
csv << headers

Although this works just fine, what I would like to do is have the call in one line without having to add the headers variable first.

So something like:

csv << ["name", "email", questions.each { |q| q }]

Obviously the above doesn't work because the each returns the 'questions' array.

Any suggestions?

Answer 1

csv << headers + questions

Answer 2

Use the splat operator as follow.

csv << ["name", "email", *questions]

Answer 3

Just use Array#+:

csv << ["name", "email"] + questions

Or a bit shorter:

csv << %w(name email) + questions

Answer 4

There's several methods to do this. I would use something like this:

headers = (['name', 'email'] << questions).flatten

See this question for more elaborate answers, also in regard to performance: How do you add an array to another array in Ruby and not end up with a multi-dimensional result?

Answer 5

["name", "email", *questions.map { |q| q }]

map returns result array