What does map(&:name) mean in Ruby?

Question

I found this code in a RailsCast:

def tag_names
  @tag_names || tags.map(&:name).join(\' \')
end

What does the (&:name)

Answer 1

Here :name is the symbol which point to the method name of tag object. When we pass &:name to map, it will treat name as a proc object. For short, tags.map(&:name) acts as:

tags.map do |tag|
  tag.name
end