ruby-blank?

>|ruby|
hoge = nil

hoge.nil? => true
hoge.empty? => ERROR
hoge.blank? => true
||<

>|ruby|
hoge = ''

hoge.nil? => false
hoge.empty? => true
hoge.blank? => true
||<

>|ruby|
hoge = 0

hoge.nil? => false
hoge.empty? => ERROR
hoge.blank? => false
||<

なるほど。。。