Class | Hashery::KeyHash |
In: |
lib/hashery/key_hash.rb
|
Parent: | CRUDHash |
The KeyHash class is a Hash class which accepts a block for normalizing keys.
The KeyHash class is essentially the same as a normal Hash. But notice the significant distinction of indifferent key access.
s = KeyHash.new s[:x] = 1 s[:x] #=> 1 s['x'] #=> 1
We can see that internally the key has indeed been converted to a String.
s.to_h #=> {'x'=>1 }
By default all keys are converted to strings. This has two advantages over a regular Hash is many usecases. First it means hash entries have indifferent access. 1, "1" and :1 are all equivalent —any object that defines to_s can be used as a key. Secondly, since strings are garbage collected so will default KeyHash objects.
But keys can be normalized by any function. Theses functions can be quite unique.
h = KeyHash.new(0){ |k| k.to_i } h[1.34] += 1 h[1.20] += 1 h[1.00] += 1 h #=> { 1 => 3 }