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?

score 2 · Accepted Answer · answered Sep 18 '13 at 08:43

2

csv << headers + questions

answered Sep 18 '13 at 08:43

zolter

oldergod · Answer 2 · 2013-09-18T08:43:23.903

1

Use the splat operator as follow.

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

edited Sep 18 '13 at 08:43

answered Sep 18 '13 at 08:41

oldergod

score 1 · Answer 3 · answered Sep 18 '13 at 08:43

1

Just use Array#+:

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

Or a bit shorter:

csv << %w(name email) + questions

answered Sep 18 '13 at 08:43

Stefan

score 1 · Answer 4 · edited May 23 '17 at 12:11

1

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

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

edited May 23 '17 at 12:11

Community

answered Sep 18 '13 at 08:46

KappaNossi

score 0 · Answer 5 · answered Sep 18 '13 at 08:41

0

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

map returns result array

answered Sep 18 '13 at 08:41

Oleg Haidul

`objects.map { |q| q }` isn't the same as `objects` ? – oldergod Sep 18 '13 at 08:42
Only in this case, but if u want to do smth with each element and return a result object u need to use `map` – Oleg Haidul Sep 18 '13 at 08:44

5 Answers5