I have this:
hash = { "a"=>["a", "b", "c"], "b"=>["b", "c"] }
and I want to get to this: [["a","b","c"],["b","c"]]
This seems like it should work but it doesn't:
hash.each{|key,value| value}
=> {"a"=>["a", "b", "c"], "b"=>["b", "c"]}
Any suggestions?
Also, a bit simpler....
>> hash = { "a"=>["a", "b", "c"], "b"=>["b", "c"] }
=> {"a"=>["a", "b", "c"], "b"=>["b", "c"]}
>> hash.values
=> [["a", "b", "c"], ["b", "c"]]
map), cos I like this a lot!
Hash#values is not only simpler, but more efficient. Compare time ruby -e '(1..1000000).reduce({}){|h,i| h.store i,i; h}.values' with time ruby -e '(1..1000000).reduce({}){|h,i| h.store i,i; h}.map{|k,v| v}'
I would use:
hash.map { |key, value| value }
Hash#values.
hash.collect { |k, v| v }
#returns [["a", "b", "c"], ["b", "c"]]
Enumerable#collect takes a block, and returns an array of the results of running the block once on every element of the enumerable. So this code just ignores the keys and returns an array of all the values.
The Enumerable module is pretty awesome. Knowing it well can save you lots of time and lots of code.
hash.values is ultimately the correct answer here.
hash.map(&:second) :)It is as simple as
hash.values
#=> [["a", "b", "c"], ["b", "c"]]
this will return a new array populated with the values from hash
if you want to store that new array do
array_of_values = hash.values
#=> [["a", "b", "c"], ["b", "c"]]
array_of_values
#=> [["a", "b", "c"], ["b", "c"]]
hash = { :a => ["a", "b", "c"], :b => ["b", "c"] }
hash.values #=> [["a","b","c"],["b","c"]]
There is also this one:
hash = { foo: "bar", baz: "qux" }
hash.map(&:last) #=> ["bar", "qux"]
Why it works:
The & calls to_proc on the object, and passes it as a block to the method.
something {|i| i.foo }
something(&:foo)
hash.valuesbeing the better IMO). But I wanted to point out when you provide a block toHash#eachit will just return the full value of the hash. If you want to do an operation on each item and return that as an array, useHash#collector its aliasHash#map. More stuff on Enumerables here.