foo(T) where T # in Vector{DataType}

General Usage
1

Hellow, how can i write a function like this:

vector_data_type = [
  Int64,
  Int32,
  Int16,
]

foo(T) where T # in vector_data_type
2

With a for loop and @eval:

julia> for T in (Int64, Int32, Int16)
           @eval foo(::$T) = string($T)
       end

julia> foo(1)
"Int64"

julia> foo(Int16(1))
"Int16"
2 Likes
3

Or perhaps you meant a case where the source is the same for all the methods and doesn’t requires any interpolation/eval. You can use a Union for many cases like that.

julia> bar(::T) where T <: Union{Int64, Int32, Int16} = string(T)
bar (generic function with 1 method)

julia> bar(1)
"Int64"

julia> bar(Int16(1))
"Int16"

julia> bar(Int8(1))
ERROR: MethodError: no method matching bar(::Int8)
3 Likes
4

You mean to define such a function?

foo(::Type{T}) where T<:Union{Int64,Int32,Int16}

but I would guess you’re actually looking for Integer (which is a supertype of all of those, but may also encapsulate other integer types)

3 Likes