def my_method(required_param, named_param_1: nil, named_param_2: nil)
named_params = method(__method__).parameters.each_with_object({}) do |p,h|
h[p[1]] = eval(p[1].to_s) if p[0] == :key
end
p named_params # {:named_param_1=>"hello", :named_param_2=>"world"}
# do something with the named params
end
my_method( 'foo', named_param_1: 'hello', named_param_2: 'world' )
How can I get named parameters into a Hash?
문제
I want to have named parameters to a method so the API is clear to the caller, but the implementation of the method needs the named parameters in a hash. So I have this:
def my_method(required_param, named_param_1: nil, named_param_2: nil)
named_params = {
named_param_1: named_param_1,
named_param_2: named_param_2
}
# do something with the named params
end
This works, but I have to do this in quite a few places, and I would rather have some helper that dynamically gets the named parameters into a hash. I haven't been able to find a way to do this. Any thoughts on how to accomplish this?
해결책
다른 팁
Ruby 2.0 provides no built-in way to get a Hash from keyword arguments.
You must choose between:
Using keyword arguments (as you currently are) and creating a Hash from those values separately, OR...
Using a Hash argument with default values, such as the Ruby v1.9.3 strategies described here.
You could do write your method as below :
def my_method(required_param, named_param_1: nil, named_param_2: nil)
named_params = Hash[method(__method__).parameters.select do |first,last|
[last,eval("#{last}")] if first == :key
end]
end
my_method(12, named_param_1: 11,named_param_2: 12)
# => {:named_param_1=>11, :named_param_2=>12}
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