Create array of symbols

140
votes

Is there a cleaner way to do something like this?

%w[address city state postal country].map(&:to_sym) 
#=> [:address, :city, :state, :postal, :country]

I would have figured %s would have done what I wanted, but it doesn't. It just takes everything between the brackets and makes one big symbol out of it.

Just a minor annoyance.

3
ruby
That's pretty standard. Is there anything about your implementation which makes this method undesirable? – dwhalen
Not "really" but Rails often has syntactical sugar like this that makes me feel all warm a tingly inside by using. :) – Drew
since ruby 2, there is ! see stackoverflow.com/questions/8816877/… – m_x
Possible duplicate of Is there a literal notation for an array of symbols? – ymoreau

3 Answers

380
votes

The original answer was written back in September '11, but, starting from Ruby 2.0, there is a shorter way to create an array of symbols! This literal:

%i[address city state postal country]

will do exactly what you want.

99
votes

With a risk of becoming too literal, I think the cleanest way to construct an array of symbols is using an array of symbols.

fields = [:address, :city, :state, :postal, :country]

Can't think of anything more concise than that.

3
votes

%i[ ] Non-interpolated Array of symbols, separated by whitespace (after Ruby 2.0)

%I[ ] Interpolated Array of symbols, separated by whitespace (after Ruby 2.0)

%i[address city state postal country]

the cleanest way to do this is:

%w[address city state postal country].map(&:to_sym)