In light of the recent discussions
(https://groups.google.com/forum/#!topic/julia-users/xJ7GpKAa16E
and https://groups.google.com/forum/#!topic/julia-users/_lIVpV0e_WI) I got
curious, whether there is a non-modifying version of push!, since
push!(copy(a),b) doesn't feel right (I try to avoid modifying functions,
except if I really need performance) and [a; b] is not type stable:
f(a) = [a; 3]
f2(a) = push!(copy(a),3)
julia> Base.return_types(f,(Array{Int64,1},))
1-element Array{Any,1}:
Array{T,N}
julia> Base.return_types(f2,(Array{Int64,1},))
1-element Array{Any,1}:
Array{Int64,1}
I couldn't find anything in the Julia docs. Of course, I could just define
my own
push(a,vars...) = push!(copy(a),vars...)
but if there is a standard way to do that, I'd prefer that. Maybe there's
also some clever way to avoid making a copy if `a` is a literal (e.g.
push([1,2])
).
The same applies to unshift, etc.
(Non-modifying `shift!` and `pop!` already exist with the names `first` and
`last`. I'd find it easier to remember `shift` and `pop` -- it would also
be more similar to `merge` vs `merge!` for dictionaries, but I guess that's
just my taste.)
