Feature #16341
Updated by Nondv (Dmitry Non) over 4 years ago
``` ruby
class Set
def to_proc
-> (x) { include?(x) } # or method(:include?).to_proc
end
end
```
Usage:
```ruby
require 'set'
banned_numbers = Set[0, 5, 7, 9]
(1..10).reject(&banned_numbers) # ===> [1, 2, 3, 4, 6, 8, 10]
```
**UPD**
also for hash:
```ruby
class Hash
def to_proc
->(key) { self[key] }
end
end
dogs = ['Lucky', 'Tramp', 'Lady']
favourite_food = { 'Lucky' => 'salmon', 'Tramp' => 'pasta', 'Lady' => 'pasta' }
food_to_order = dogs.map(&favourite_food)
```