Test whether a variable equals either one of two values

Question

I want to test whether a equals 1 or 2

I could do

a == 1 || a == 2 

but this requires repeating a (which would be annoying for longer variables)

I'd like to do something like a == (1 || 2), but obviously this won't work

I could do [1, 2].include?(a), which is not bad, but strikes me as a bit harder to read

Just wondering how do to this with idiomatic ruby

Answer 1

Your first method is idiomatic Ruby. Unfortunately Ruby doesn't have an equivalent of Python's a in [1,2], which I think would be nicer. Your [1,2].include? a is the nearest alternative, and I think it's a little backwards from the most natural way.

Of course, if you use this a lot, you could do this:

class Object   def member_of? container     container.include? self   end end 

and then you can do a.member_of? [1, 2].

Answer 2

I don't know in what context you're using this in, but if it fits into a switch statement you can do:

a = 1 case a when 1, 2   puts a end 

Some other benefits is that when uses the case equality === operator, so if you want, you can override that method for different behavior. Another, is that you can also use ranges with it too if that meets your use case:

when 1..5, 7, 10