Julia: Union type

By using Union, you can create a custom type, which can support instances of any of its argument types, constructed using the special Union function.

julia> IntOrStringOrbool = Union{Int,AbstractString, Bool}
Union{AbstractString,Bool,Int64}

julia> 12::IntOrStringOrbool
12

julia> "hari"::IntOrStringOrbool
"hari"

julia> true::IntOrStringOrbool
true

julia> 10.23::IntOrStringOrbool
ERROR: TypeError: typeassert: expected Union{AbstractString,Bool,Int64}, got Float64

IntOrStringOrbool = Union{Int,AbstractString, Bool}

You can assign a value of type Int (or) AbstractString (or) Bool to the type IntOrStringOrbool. You will get TypeError, when you try to assign any other kind of data.

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