Array include any value from another array?
How about Enumerable#any?
>> cheeses = %w(chedder stilton brie mozzarella feta haloumi)
=> ["chedder", "stilton", "brie", "mozzarella", "feta", "haloumi"]
>> foods = %w(pizza feta foods bread biscuits yoghurt bacon)
=> ["pizza", "feta", "foods", "bread", "biscuits", "yoghurt", "bacon"]
>> foods.any? {|food| cheeses.include?(food) }
=> true
Benchmark script:
require "benchmark"
N = 1_000_000
puts "ruby version: #{RUBY_VERSION}"
CHEESES = %w(chedder stilton brie mozzarella feta haloumi).freeze
FOODS = %w(pizza feta foods bread biscuits yoghurt bacon).freeze
Benchmark.bm(15) do |b|
b.report("&, empty?") { N.times { (FOODS & CHEESES).empty? } }
b.report("any?, include?") { N.times { FOODS.any? {|food| CHEESES.include?(food) } } }
end
Result:
ruby version: 2.1.9
user system total real
&, empty? 1.170000 0.000000 1.170000 ( 1.172507)
any?, include? 0.660000 0.000000 0.660000 ( 0.666015)
(cheeses & foods).empty?
As Marc-André Lafortune said in comments, &
works in linear time while any?
+ include?
will be quadratic. For larger sets of data, linear time will be faster. For small data sets, any?
+ include?
may be faster as shown by Lee Jarvis' answer -- probably because &
allocates a new Array while another solution does not and works as a simple nested loop to return a boolean.