Marshal ruby hash with default proc - remove the default proc?

问题

I've got a Hash with a default proc that I'd like to Marshal to a file, but the default proc prevents me from doing that.

Rather than writing my own _dump and _load methods, is it possible instead to remove the default proc instead? At the point where I'm Marshalling I'm never going to need the default proc again.

回答1:

Just reset the default:

h.default = nil

More explicitly:

def dumpable_hash(h)
  return h unless h.default_proc
  copy = h.clone  
  copy.default = nil # clear the default_proc
  copy
end

In Ruby 2.0, you can also write h.default_proc = nil if you prefer. Available for all Rubies with require 'backports/2.0.0/hash/default_proc'.

回答2:

In case you would want to have a copy without defaults, the simplest way -

Hash[hash_with_defaults]

来源：https://stackoverflow.com/questions/3818623/marshal-ruby-hash-with-default-proc-remove-the-default-proc