Is it possible to avoid stating the arguments in an anonymous function? x = (a=1,b=2) ( (a,b) -> a+b )(x...) works fine, but could you do something like ( (_...) -> a+b )(x...) x would have to contain elements a and b. Otherwise there would be a run-time error.

I think you can only do that with varags, and it’s not exactly what you want but x = (a...) -> sum(a) julia> x(1,2,3) 6

[image] Lincoln_Hannah: ( (_…) → a+b )(x…) what does this mean? (i.e. what do you want it to do?) For example, what even is a,b? If you want to do something and don’t care about the argument, you should julia> x (a = 1, b = 2) julia> values(x) (1, 2) julia> sum(x) 3

I’d like to use variables in the body of a function without listing them explicitly as function inputs. (probably not possible. just thought I’d check)

[image] Lincoln_Hannah: in the body of a function without listing them explicitly as function inputs how is that logically possible? how does the function know what variables to use then? maybe you’re thinking about closure? julia> g(y0) = x-> x+y0 g (generic function with 1 method) julia> …

Background – For DataFrames, I’d like an easy way to do row-level operations, and use the column names as variable names and have any created variables added automatically as new columns. in this discussing a nice method was suggested [image] Apply function By Row without re-stat…

Yes. DataFramesMeta.jl does exactly this. julia> df = DataFrame(a = [1, 2, 3], b = [5, 6, 7]); julia> @rtransform df begin :c = :a + :b :d = :a - :b end 3×4 DataFrame Row │ a b c d │ Int64 Int64 Int64 Int64 ─────┼──────────────────────────── …

I have DataFramesMeta installed but for some reason @rtransform isn’t recognised

Check your version. Current version is 0.9.1 @rtransform should be in 0.9.0 and newer.

works :slight_smile: thank you so much. is there any way to avoid the colons in the variable names? Related question - there are various DF filtering functions @where, @subset All seem to require vectorising the conditional statement eg :a .> 3. Is there a way of doing @rsubset so you…

No, you can’t avoid the colons. Columns are referenced as :x. The reason for this is that we need a way to distinguish, at parse time, the columns in a data frame from other variables. Without knowing anything about the data frame. x = 1 @rtransform df :y = :x + x Obviously it’s possible to make …

Can you avoid stating the arguments in an anonymous function?

General Usage

Lincoln_Hannah October 18, 2021, 12:07am 14

Had some more questions. Put them in a new topic with appropriate heading.

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Can you avoid stating the arguments in an anonymous function?

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