Using zip or enumerate within IF?

New to Julia
1

Hello,
Is there a way to use zip() or enumerate() within the IF statement?
I’m looking for a safter way to run the code below. I’ve created structs to dispatch an appropriate model based off a “category” in a dataframe. Currently it’s only dispatching the custom models correctly because custom_cats and custom_cats_structs are aligned (that is when looping through category: Custom 1, Struct: custom_a is the appropriate choice).

It seems like doing something like zip(custom_cats, custom_cats_structs) would be safer / more preferred way, but I can’t seem to figure out what the right syntax is.

Here’s what I have (which works, but again seems suboptimal):

struct general end
struct custom_a end
struct custom_b end

df = DataFrame(category=["Normal 1", "Normal 2", "Normal 3", "Custom 1", "Custom 2"], X=[5, 4, 8, 9,10], Y =[1000,5000,3000,1200,5000])

cats = ["Normal 1", "Normal 2", "Normal 3", "Custom 1", "Custom 2"]
normal_cats = ["Normal 1", "Normal 2", "Normal 3"]
custom_cats = ["Custom 1", "Custom 2"]
custom_cats_structs = [custom_a(),custom_b()]

function mymodel(x::general)
    println("Genearl Model Hello")
end

function mymodel(x::custom_a)
    println("This is my first custom model")
end

function mymodel(x::custom_b)
    println("This is my second custom model")
end

function run_models(cats,norm,cust,cust_structs)
    for c in cats
        println("working on $c")
        if c in norm
            mymodel(general())
        elseif c in cust
            n = 1
            mymodel(cust_structs[n])
            n+1
        end
    end
end

run_models(cats,normal_cats,custom_cats,custom_cats_structs)

Hope this makes sense. Thanks for your help.

2 
julia> a = [1, 2, 3, 4]; b = [100, 200, 300, 400];

julia> for (ai, bi) in zip(a, b)
           println("ai: ", ai)
           println("bi: ", bi)
       end
ai: 1
bi: 100
ai: 2
bi: 200
ai: 3
bi: 300
ai: 4
bi: 400
3

Can we ask what the higher level goal is? Like, what end result do you want to get e.g. print something for each item in the data frame? While attempting a solution is good, it can lead to so-called “XY problems”. I also don’t quite understand what the current goal is either.

4

You essentially have an associative map. The datastructure for this is Dict. Here’s how I would do it:

struct General end
struct CustomA end
struct CustomB end

categories = ["Normal 1", "Normal 2", "Normal 3", "Custom 1", "Custom 2"]
custom_category_selectors = Dict("Custom 1" => CustomA(), "Custom 2" => CustomB())

function mymodel(x::General)
    println("General Model Hello")
end

function mymodel(x::CustomA)
    println("This is my first custom model")
end

function mymodel(x::CustomB)
    println("This is my second custom model")
end

function run_models(categories, custom_selectors)
    for c in categories
        println("working on $c")
        selector = get(custom_selectors, c, General())  # Defaults to General() when c is not a key in custom_selectors
        mymodel(selector)
    end
end

run_models(categories, custom_category_selectors)

# Output
working on Normal 1
General Model Hello
working on Normal 2
General Model Hello
working on Normal 3
General Model Hello
working on Custom 1
This is my first custom model
working on Custom 2
This is my second custom model
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