Why do most programming languages only have binary equality comparison operators?

Question

In natural languages, we would say \"some color is a primary color if the color is red, blue, or yellow.\"

In every programming language I\'ve seen, that translates

Answer 1

Ruby

Contained in list:

irb(main):023:0> %w{red green blue}.include? "red"
=> true
irb(main):024:0> %w{red green blue}.include? "black"
=> false

Numeric Range:

irb(main):008:0> def is_valid_num(x)
irb(main):009:1>   case x
irb(main):010:2>     when 1..100, 1000..2000 then true
irb(main):011:2>     else false
irb(main):012:2>   end
irb(main):013:1> end
=> nil
irb(main):014:0> is_valid_num(1)
=> true
irb(main):015:0> is_valid_num(100)
=> true
irb(main):016:0> is_valid_num(101)
=> false
irb(main):017:0> is_valid_num(1050)
=> true