Question

Python has really elegant syntax for checking a value against several patterns.

2 in [1,2,4] #=> True
6 in [1,2,4] #=> False

Order in Ruby version just feels wrong:

[1,2,4].include?(2)

I understand that include? makes a lot more OO sense than 2.included_in?([1,2,4]), I still don’t like it. Ruby even has in keyword but it seems to only be used in construct for i in [1,2,4], not for membership tests.

Another way is this:

(case 2 when 1,2,4 then true end)

Quite verbose, but allows patterns test:

(case file_name when "README", /\.txt\z/ then true end)

Still not very readable.

Am I missing some really nifty way by chance?

Answer 1

$ gem install sane

$ irb

 >> 3.in? [1,2,3]
 >> true