ruby - How might I treat nil values as zero when adding numbers? -

i have method looks this:

def calculate_the_thing(hsh)   hsh[:x] + hsh[:y] + hsh[:z] end

which takes this:

{:x => 5, :y => nil, :z => 2, :a => 5}

i'd patch classes when + method gets nil value, treats zero. seems reasonable. how might that?

as @jforberg points out, can use #to_i method return 0 nil.

def calculate_the_thing(hsh)   hsh[:x].to_i + hsh[:y].to_i + hsh[:z].to_i end

alternatively, can define hash automatic default value...

hsh = hash.new{0}

but if have method explicitly puts nil hash value override default value.

Ben