Including empty k/v pairs when merging hashes - ruby

Question

There are three hashes. Each hash results in a single key/value pair.
When merged and outputted to a json file, the only k/v pairs visible are the ones with data.
For example:
employee_hours[ name ] = {"Hours" => hours}
employee_revenue [ name ] = {"Revenue" => revenue}
employee_activations [ name ] = {"Activations" => activations}
If any of the k/v pairs don't exist I need them to be included in the output with a value of 0.00.
I tried to simply just include empty k/v pairs from the other hashes in each hashtable, but when merged, they overwrite existed values.
employee_hours[ name ] = {"Hours" => hours, "Revenue" = "", Activations = ""}
employee_revenue [ name ] = {"Hours" => "", "Revenue" => revenue, Activations = ""}
employee_activations [ name ] = {"Hours" => "", "Revenue" => "", "Activations" => activations}
Edit
My current code is listed here: https://gist.github.com/hnanon/766a0d6b2b0f9d9d03fd

Answer 1

You need to define a hash for the default values and merge into it. Assuming that employee_final is the hash where you merged all the employee information,
employee_defaults = { "Hours" => 0.0, "Revenue" => 0.0 }
employee_final.each_key do |name|
employee_final[name] = employee_defaults.merge(employee_final[name])
end

Answer 2

It sounds as if you need to define a 'REQUIRED_KEYS' array, and add check on their existence in your hashes. Here's one way to achieve that:
REQUIRED_KEYS = [ "A", "B", "C" ]
DEFAULT_VALUE = 0.0
REQUIRED_KEYS.each { |key| your_hash[key] = DEFAULT_VALUE if not your_hash.has_key?(key) }

Answer 3

Use Hash Defaults
You can use an argument to Hash#new to set a default value for a hash. For example:
require 'json'
employee_hours = Hash.new(0.0)
employee_revenue = Hash.new(0.0)
employee_activations = Hash.new(0.0)
name = 'Bob'
{
'Hours' => employee_hours[name],
'Revenue' => employee_revenue[name],
'Activations' => employee_activations[name],
}.to_json
# => "{\"Hours\":0.0,\"Revenue\":0.0,\"Activations\":0.0}"