We can check if a variable is an array in Ruby using Object#is_a?.
{{code:php $colors = array('red', 'green', 'blue'); $result = is_array($colors); var_export($result); // => true }}
{{code:ruby colors = ["red", "green", "blue"] p colors.is_a?(Array) # => true }}
{{related: var/is_float var/is_int var/is_string var/is_object }}