Check whether a value is present in an array in Ruby

Question:

How to check if a certain value is contained in an array in Ruby? For example, I want to know if 'A' is present in the vector ['A','B','C'] .

Answer:

Use the include? method include? .

a = [ "a", "b", "c" ]
a.include?("b")   #=> true
a.include?("z")   #=> false