nil? zero? blank? の動きの違い

gistfile1.txt

[参考ページ]
blank? nil? zero?: Rails開発日記
 - [ http://underrails.seesaa.net/article/135698039.html ]

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0.nil? #=> false
0.zero? #= true
0.empty? #=> NoMethodError
0.blank? #=> false
0 == false #=> false

"".nil? #=> false
"".zero? #=> NoMethodError
"".empty? #=> true
"".blank? #=> true
"" == false #=> false

{}.nil? #=> false
{}.zero? #=> NoMethodError
{}.empty? #=> true
{}.blank? #=> true
{} == false #=> false

[].nil? #=> false
[].zero? #=> NoMethodError
[].empty? #=> true
[].blank? #=> true
[] == false #=> false

nil.nil? #=> true
nil.zero? #=> NoMethodError
nil.empty? #=> NoMethodError
nil.blank? #=> true
nil == false #=> false

false.nil? #=> false
false.zero? #=> NoMethodError
false.empty? #=> NoMethodError
false.blank? #=> true
false == false #=> true