What is an object? Objects are like "boxes". Therefore, when checking for existence,
Let's look at it from the perspective of.
"The box does not exist or the contents do not exist" By the way, ** Rails-only method **
obj.blank? #Synonymous obj.nil? || obj.empty?
"There is a box and there are contents" By the way, ** Rails-only method **
obj.present? #Synonymous !obj.nil? && !obj.empty? obj.blank?