How do I create a function that can take either positional or keyword arguments? Right now, I have a function that takes keyword arguments. But, I would to revise it to take either positional or keyword arguments. Thanks.

@mkborregaard @ChrisRackauckas : Here is a workaround to the above problem. Any advice/comments? Thanks a lot. function tryFunction(; x::Int64=nothing,y::Int64=nothing) if x == nothing || y == nothing error("Specify arguments") end tryFunction(x::Int64, y::Int64) end function tryFunction(…

Since the argument defaults get evaluated at call time, you can actually have the default itself be an expression that throws an error: julia> f(;x::Int=throw(ArgumentError("missing x"))) = x f (generic function with 1 method) julia> f(x=2) 2 julia> f() ERROR: ArgumentError: missing x in f() at …

@mbauman : @mkborregaard : Thanks. How do I combine this with the function so it takes positional arguments as well to fit into the tryFunction I wrote above?

@mbauman : I tried to replicate the same function in Atom.But, it did not run. Any idea? Thanks. f(; x::Int=throw(ArgumentError("missing x"))) return(x) end I got this error message; syntax: keyword argument is not a symbol: "x::Int" in include_string(::String, ::String) at loading.jl:441 in …

You’re missing the function (or to do like the example, where the function was defined in a short form using = x).

This tryFunction approach works, of course. There is nothing wrong with it :slight_smile: I was just curious of why you wanted to achieve this design.

@mkborregaard : oh, my bad. So, that works without function in REPL , but in ATOM?? Thanks.

@mkborregaard : I just wanted to have that flexibility in case people would ask. I love Julia language, and I would like to give people no chance to discard the fact that this is an awesome language Thanks.

It’s not about the REPL or Atom. It is simply that there are two ways of defining a function: f(x) = println(x) # or function f(x) println(x) end They are equivalent. But you tried a mix between the two, e.g. you tried something like this: f(x) println(x) end That doesn’t work.

I’ve actually written a little package called RequiredKeywords.jl that implements this solution using a macro. You can use it like julia> using RequiredKeywords julia> @required_keywords f(x; y) = x*y f (generic function with 1 method) julia> f(2,y=2) 4 julia> f(2) ERROR: Unassigned Keyword: Re…

Make function arguments positional or keyword

General Usage

mkborregaard April 1, 2017, 5:40am 19

This tryFunction approach works, of course. There is nothing wrong with it I was just curious of why you wanted to achieve this design.

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Make function arguments positional or keyword

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