How to replace all nil value with "" in a ruby hash recursively?

hash, proc, ruby

Solution

Here is a recursive method that does not change the original hash.

Code

def denilize(h)
  h.each_with_object({}) { |(k,v),g|
    g[k] = (Hash === v) ?  denilize(v) : v.nil? ? '' : v }
end

Examples

h = { "a"=>{ "b"=>{ "c"=>nil } } }
denilize(h) #=> { "a"=>{ "b"=>{ "c"=>"" } } }

h = { "a"=>{ "b"=>{ "c"=>nil , "d"=>3, "e"=>nil}, "f"=>nil  } }
denilize(h) #=> { "a"=>{ "b"=>{ "c"=>"" , "d"=>3, "e"=>""}, "f"=>"" } }

Problem

``` str = "<a><b><c></c></b></a>" hash = Hash.from_xml(str) # => {"a"=>{"b"=>{"c"=>nil}}} ``` How can I replace all `nil`s in a Hash to `""` so that the hash becomes: ``` {"a"=>{"b"=>{"c"=>""}}} ```

Original source