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From a hash like the below one, need to extract the unique values per key
array_of_hashes = [ {'a' => 1, 'b' => 2 , 'c' => 3} ,
{'a' => 4, 'b' => 5 , 'c' => 3},
{'a' => 6, 'b' => 5 , 'c' => 3} ]
Need to extract the unique values per key in an array
unique values for 'a' should give
[1,4,6]
unique values for 'b' should give
[2,5]
unique values for 'c' should give
[3]
Thoughts ?
855
In Ruby, a hash is a collection of key-value pairs. A hash is denoted by a set of curly braces ( {} ) which contains key-value pairs separated by commas. Each value is assigned to a key using a hash rocket ( => ). Calling the hash followed by a key name within brackets grabs the value associated with that key.
A Hash is a dictionary-like collection of unique keys and their values. Also called associative arrays, they are similar to Arrays, but where an Array uses integers as its index, a Hash allows you to use any object type. Hashes enumerate their values in the order that the corresponding keys were inserted.
A Hash is a collection of key-value pairs. It is similar to an Array , except that indexing is done via arbitrary keys of any object type, not an integer index.
Use Array#uniq:
array_of_hashes = [ {'a' => 1, 'b' => 2 , 'c' => 3} ,
{'a' => 4, 'b' => 5 , 'c' => 3},
{'a' => 6, 'b' => 5 , 'c' => 3} ]
array_of_hashes.map { |h| h['a'] }.uniq # => [1, 4, 6]
array_of_hashes.map { |h| h['b'] }.uniq # => [2, 5]
array_of_hashes.map { |h| h['c'] }.uniq # => [3]
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