In Ruby on Rails Programming you might have to check if key exists in hash and based on that you might have to perform other operation. There is a simple way to detect if key exists in particular hash.
Ruby hash contains Key-Value pairs. In Ruby, you can create a simple hash as follows,
Above code will initialize empty hash. Let’s add some key value pair in the
The above code will add ‘name’ key and ‘Ruby in Rails’ as it’s value.
Let’s add one more key-value pair in the
How to check if key exists in hash
You can check if particular key exists in a hash or not by using has_key? method available for the hash object in ruby.
||This will return true/false by
checking if key
hash object for which the method is invoked
This will return true as
name key exists in the my_hash hash
Above code returns false as my_hash doesn’t contain any key with named
Performance of Hash#has_key? versun Array#include?
|Time Complexity||o(1) operation||o(n) operation|
|Access Type||Accesses Hash[key] if
it returns any value
then true is returned
to the Hash#has_key? call
|Iterates through each
element of the array till it
finds the value in Array
You can find more about ruby hashes and various methods that can be used with hashes on apidock. We learned how to check if key exists in a hash for Ruby language and compared it with include operation on arrays.
has_key is faster as it is o(1) lookup as explained above.