blank,empty and nil in Ruby

Object.blank?

Returns true if:
> it’s an empty array
> it’s an empty string
> !self evaluates to true

[].blank? #=> true
[1].blank? #=> false
[nil].blank? #=> false
nil.blank? #=> true
true.blank? #=> false
false.blank? #=> true
"".blank? #=> true
" ".blank? #=> true
" i ".blank? #=> false

String.empty?

"hello".empty? #=> false
"".empty? #=> true

Array.empty?
[].empty? #=> true

Hash.empty?
{}.empty? #=> true

NilClass.nil?
nil.nil? => true

Object.nil?
nil.nil? => true
.nil? => false
nil.inspect ? "nil"