Ruby enumerable: #all? #any? #empty? #none?

all_any_empty_none.rb

# The peculiarities of #all?, #any?, #empty?, #none?
ary = []


ary.all?    # => true
ary.any?    # => false
ary.empty?  # => true
ary.none?   # => true



ary_true = [true]

ary_true.all?    # => true
ary_true.any?    # => true
ary_true.empty?  # => false
ary_true.none?   # => false



ary_false = [false]

ary_false.all?    # => false
ary_false.any?    # => false
ary_false.empty?  # => false
ary_false.none?   # => true



ary_nil = [nil]

ary_nil.all?    # => false
ary_nil.any?    # => false
ary_nil.empty?  # => false
ary_nil.none?   # => true