Le samedi 23 juillet 2016 à 11:37 -0700, 'George Marrows' via julia-
users a écrit :
> Hi. As per the docs on splice! and n:(n-1) ranges, the following
> works fine to insert a value before location 1 in a Vector:
> x = [1,2,3]
> splice!(x, 1:0, 23)
> print(x) # => [23,1,2,3]
This example works, but only as a special-case of '23' being taken as
equivalent to '[23]'.
> But the following behaves strangely and seems to corrupt the array in
> the process:
> a = Vector{UInt8}[UInt8[0xf3,0x32,0x37]]
> splice!(a, 1:0, UInt8[7,3]) # => MethodError: `convert` has no
> method matching convert(::Type{Array{UInt8,1}}, ::UInt8)
> print(a) # => [#undef,#undef,UInt8[0xf3,0x32,0x37]]
This example fails because 'a' is a vector of vectors, so you need to
pass a vector of vectors to splice!() too. Since you pass it a vector
of UInt8, it tries to insert UInt8 values into a, which isn't possible.
The failure comes from 'convert(Vector{UInt8}, 7)'.
Try with
splice!(a, 1:0, Vector{UInt8}[UInt8[7,3]])
The array corruption is a different issue which is hard to fix:
checking whether conversion will succeed before resizing the array
hurts performance a lot, so currently if conversion fails the array is
resized anyway. This might be fixed at some point if a good solution is
found. See https://github.com/JuliaLang/julia/issues/15868
Regards
> Is this a bug, or have I simply not read the docs correctly?
