I have a hash and an array. I want to check whether an array element is in the hash as a key, and if not, delete the key from the hash.
RegionScoreHash={"A"=>1, "B"=>0, "C"=>0, "D"=>1, "E"=>0, "F"=>0, "G"=>0}
RegionsArray=["B", "C", "D", "E", "F"]
Result Required: Hash with elements present in array (A and G regions removed)
ResultHash={"B"=>0, "C"=>0, "D"=>1, "E"=>0, "F"=>0}
Use Array's delete_if method to modify the hash in place.
RegionScoreHash.delete_if { |k| !RegionsArray.include?(k) }
or use something like select if you want a new result.
result = RegionScoreHash.select { |k| RegionsArray.include?(k) }
Deleting is inefficient.
ResultHash = RegionsArray.inject({}){|h, k| h[k] = RegionScoreHash[k]; h}
Try this
RegionScoreHash={"A"=>1, "B"=>0, "C"=>0, "D"=>1, "E"=>0, "F"=>0, "G"=>0}
RegionsArray=["B", "C", "D", "E", "F"]
RegionScoreHash.delete_if {|a| !RegionsArray.include?(a)}
As advice the ruby way should be region_score_hash instead RegionScoreHash.
Since you've tagged ruby-on-rails, let's assume you have ActiveSupport's extensions to Enumerable, which allows use of exclude?
Combine it with Hash's delete_if method
RegionScoreHash.delete_if { |k, _v| RegionsArray.exclude?(k) }
and you should get back a hash with only keys that are present in RegionsArray.
