Check if keyword arguments exist in Julia

Question

I have a function collect extra keyword arguments using ..., so it is like function f(args=0; kwargs...). I want to check if a keyword argument, let' say, a, exists in kwargs.

What I do probably is not an elegant way, I first create a Dict to store the keywords and corresponding values kwargs_dict=[key=>value for (key, value) in kwargs], then I use haskey(kwargs_dict, :a) to check if a is a key in the dict. Then I get its value by kwargs_dict[:a].

function f(; kwargs...)
   kwargs_dict = [key=>value for (key, value) in kwargs]
   haskey(kwargs_dict, :a)
   a_value = kwargs_dict[:a]
end

f(args=0, a=2)
> true

f(args=0)
> false

I wonder if there is better way to check if the keyword argument a is in kwargs and to get the value of the existed keyword argument.

Answer 1

You can just pass kwargs to the Dict constructor to get a dictionary representation of the kwargs. For example:

kwargs_dict = Dict(kwargs)