On Sat, Jan 9, 2016 at 2:25 PM, Alexandr <[email protected]> wrote:
>
>
>> See the manual I linked. Float64 <: Number does not imply
>> Vector{Float64} <: Vector{Number}
>
> Sorry, I didn't notice it. Thanks!
>
> But what is then a proper way to define a function whose argument is
> either Vector{Float64} or Vector{Int64}?
A few lines down on the same page.
function norm{T<:Real}(p::Point{T})
sqrt(p.x^2 + p.y^2)
end
>
>
> On 1/9/2016 8:17 PM, Yichao Yu wrote:
>> On Sat, Jan 9, 2016 at 1:48 PM, Alexandr <[email protected]> wrote:
>>> I am using Version 0.4.0 (2015-10-08 06:20 UTC)
>>>
>>> I restarted Julia repl/intrpreter.
>>>
>>> Below is a complete code where I am trying to solve my task in a two ways:
>>>
>>> 1) by defining a Union of the types
>>>
>>> 2) by specifying the type of elements in the input vector as "Number".
>>> (Is it correct to do it?)
>>> Because according to the types hierarchy here:
>>> https://en.wikibooks.org/wiki/Introducing_Julia/Types
>>> both Int and Float are subtypes of super type Number and Real.
>>>
>>> #------------------------------------#
>>> IntOrFloat = Union{Int, AbstractFloat}
>>>
>>> function ff1(v::Array{IntOrFloat,1})
>>> mean(v)
>>> end
>>> println( ff1([1.0, 2.0]) )
>>>
>>> function ff2(v::Vector{IntOrFloat})
>>> mean(v)
>>> end
>>> println( ff2([1.0, 2.0]) )
>>>
>>> function ff3(v::Vector{Number})
>>> filter(x-> x>=1.5, v)
>>> end
>>> ff3([1.0, 2.0, 3.0, 5.0])
>>>
>>> #------------------------------------#
>>> Output errors:
>>>
>>> ERROR: LoadError: MethodError: `ff1` has no method matching
>>> ff1(::Array{Float64,1})
>>>
>>> ERROR: LoadError: MethodError: `ff2` has no method matching
>>> ff2(::Array{Float64,1})
>>>
>>> ERROR: LoadError: MethodError: `ff3` has no method matching
>>> ff3(::Array{Float64,1})
>>>
>>> #------------------------------------#
>>
>> The signature of the first and second functions are exactly the same
>> and all three gives error as expected.
>>
>> See the manual I linked. Float64 <: Number does not imply
>> Vector{Float64} <: Vector{Number}
>>
>>>
>>>
>>> On 1/9/2016 7:32 PM, Yichao Yu wrote:
>>>>>
>>>>> Which version are you using? `f1` shouldn't match either and it's a
>>>>> bug if it does.
>>>>
>>>> Also check if you've already defined another `f1` that does accept the
>>>> arrays of different types.
>>>>
>>>> And for why neither of them should match. See
>>>> http://julia.readthedocs.org/en/latest/manual/types/#parametric-composite-types
>>>>
>>>>>
>>>>>>
>>>>>> --
>>>>>> Alexandr
>>>
>>> --
>>> Alexandr
>
> --
> Alexandr
