Correctly check for empty/filled array

array_check.rb

arr = []

# You probably know this one:

#http://ruby-doc.org/core-2.0.0/Array.html#method-i-empty-3F
if arr.empty?
  # do something
end

# But do you also know the opposite?

arr = ['array', 'with', 'stuff', 'in', 'it']

unless arr.empty?
  # do something
end

# nice try, but there is also a predicate

# http://ruby-doc.org/core-2.0.0/Enumerable.html#method-i-any-3F
if arr.any?
  # do something
end

# Hey, but what about nil values?

if arr && arr.any?
  # do something
end

if arr.nil? ||arr.empty?
  # do something
end

# If you have ActiveSupport you can do this with one predicate:

# for empty arrays:
# http://api.rubyonrails.org/classes/Object.html#method-i-blank-3F
if arr.blank?
  # do something
end

# for filled arrays:
# http://api.rubyonrails.org/classes/Object.html#method-i-present-3F
if arr.present?
  # do something
end