NamedTupleTools.jl

julia> using NamedTupleTools
julia> namesofvalues  = (:instrument, :madeby)
julia> matchingvalues = ("violin", "Stradivarius")

julia> nt = namedtuple(namesofvalues, matchingvalues)
(instrument = "violin", madeby = "Stradivarius")

julia> using NamedTupleTools

julia> nt = NamedTuple{(:a, :b)}(1.0, "two")
(a = 1.0, b = "two")

julia> typeof(nt) == NamedTuple{(:a, :b),Tuple{Float64,String}}
true

julia> propertynames(nt) == (:a, :b)
true

julia> fieldnames(nt) == (:a, :b)             # synonym for the moment
true

julia> fieldtypes(nt) == (Float64, String)
true

julia> valtype(nt) == Tuple{Float64, String}
true

julia> fieldvalues(nt) == (1.0, "two")
true

using NamedTupleTools

julia> namedtuple(:a, :b, :c)(1, 2.0, "three")
(a = 1, b = 2.0, c = "three")

#=
    namedtuple(  name1, name2, ..  )
    namedtuple( (name1, name2, ..) )
       where the `names` are all `Symbols` or all `Strings`

Generate a NamedTuple prototype by specifying or obtaining the fieldnames.
The prototype is applied to fieldvalues, giving a completed NamedTuple.
=#
julia> nt = (a = 1, b = "two")
(a = 1, b = "two")

julia> nt_prototype = prototype(nt)
NamedTuple{(:a, :b),T} where T<:Tuple

julia> nt_prototype = namedtuple(:a, :b)
NamedTuple{(:a, :b),T} where T<:Tuple

julia> nt = nt_prototype(1, 2)
(a = 1, b = 2)

julia> nt = nt_prototype("A", 3)
(a = "A", b = 3)

julia> isprototype(nt_prototype)
true

julia> isprototype(nt)
false

using NamedTupleTools

julia> nt = (a = 1, b = 2, y = 25, z = 26)
(a = 1, b = 2, y = 25, z = 26)

julia> ay = select(nt, (:a, :y))
(a = 1, y = 25)

using NamedTupleTools

julia> ntproto = namedtuple( :a, :b, :c );
NamedTuple{(:a, :b, :c),T} where T<:Tuple

julia> delete(ntproto, :b) === namedtuple(:a, :c)
true

julia> fieldnames(delete(ntproto, :b))
NamedTuple{(:a, :c),T} where T<:Tuple

julia> fieldnames(delete(ntproto, (:a, :c)), fieldnames(delete(ntproto, :a, :c)
(:b,), (:b,)

julia> nt = ntproto(1, 2, 3)
(a = 1, b = 2, c = 3)

julia> delete(nt, :a)
(b = 2, c = 3)

julia> delete(nt, :a, :c)
(b = 2,)

# merge from 2..7 NamedTuples

julia> ntproto1 = namedtuple(:a, :b);
julia> ntproto2 = namedtuple(:b, :c);

julia> merge(ntproto1, ntproto2)
NamedTuple{(:a, :b, :c),T} where T<:Tuple

julia> nt1 = (a = 3, b = 5);
julia> nt2 = (c = 8,);

julia> merge(nt1, nt2)
(a = 3, b = 5, c = 8)

julia> nt1 = (a = 3, b = 5);
julia> nt2 = (b = 6, c = 8);

julia> merge(nt1, nt2)
(a = 3, b = 6, c = 8)

#=
Recursively merge namedtuples. Where more than one of the namedtuple args share the same fieldname (same key),
    the leftmost argument's key's value will be propogated. Where each namedtuple has distinct fieldnames (keys),
    all of named fields will be gathered with their respective values. The named fields will appear in the same
    order they are encountered (leftmost arg, second leftmost arg, .., second rightmost arg, rightmost arg).

If there are no nested namedtuples, `merge(nt1, nts..., recursive=true)` is the same as `merge(nt1, nts...)`.
=#

a = (food = (fruits = (orange = "mango", white = "pear"),
             liquids = (water = "still", wine = "burgandy")))

b = (food = (fruits = (yellow = "banana", orange = "papaya"),
             liquids = (water = "sparkling", wine = "champagne"), 
             bread = "multigrain"))

merge(b,a)  == (fruits  = (orange = "mango", white = "pear"), 
                liquids = (water = "still", wine = "burgandy"),
                bread   = "multigrain")

merge_recursive(b,a) == 
               (fruits  = (yellow = "banana", orange = "mango", white = "pear"), 
                liquids = (water = "still", wine = "burgandy"),
                bread   = "multigrain")

merge(a,b)  == (fruits  = (yellow = "banana", orange = "papaya"),
                liquids = (water = "sparkling", wine = "champagne"),
                bread   = "multigrain")

merge_recursive(a,b) == 
               (fruits  = (orange = "papaya", white = "pear", yellow = "banana"),
                liquids = (water = "sparkling", wine = "champagne"),
                bread   = "multigrain")

julia> using NamedTupleTools

julia> nt = (a = 1, b = 2, c = 3, d = 4);

julia> split(nt, :a)
((a = 1,), (b = 2, c = 3, d = 4))

julia> split(nt, (:a, :b))
((a = 1, b = 2), (c = 3, d = 4))

julia> merge(split(nt, (:a, :b))...) == nt
true

julia> nt = (a = 1, b = 2)
(a = 1, b = 2)

julia> convert(Dict, nt)
Dict{Symbol,Int64} with 2 entries:
  :a => 1
  :b => 2
  
julia> adict = Dict(:a => 1, :b => "two")
Dict{Symbol,Any} with 2 entries:
  :a => 1
  :b => "two"

julia> nt = namedtuple(adict)
(a = 1, b = "two")

julia> convert(Dict, nt)
Dict{Symbol,Union{Int64, String}} with 2 entries:
  :a => 1
  :b => "two"

julia> nt = namedtuple(adict)
(a = 1, b = 2//11, c = "three")

julia> convert(Dict, nt)
Dict{Symbol,Union{Rational{Int64}, Int64, String}} with 3 entries:
  :a => 1
  :b => 2//11
  :c => "three"

julia> using OrderedCollections: OrderedDict, LittleDict

julia> ldict = OrderedDict(:a => 1, :b => "two")
OrderedDict{Symbol,Any} with 2 entries:
  :a => 1
  :b => "two"

julia> nt = namedtuple(ldict)
(a = 1, b = "two")

julia> convert(LittleDict, nt)
LittleDict{Symbol,Union{Int64, String},Array{Symbol,1},Array{Union{Int64, String},1}} with 2 entries:
  :a => 1
  :b => "two"

julia> vec = [:a => 1, :b => 2]
2-element Array{Pair{Symbol,Int64},1}:
 :a => 1
 :b => 2

julia> nt = namedtuple(vec)
(a = 1, b = 2)

julia> nt = (a=1, b=2);
julia> convert(Vector{Pair}, nt)
2-element Array{Pair{Symbol,Int64},1}:
 :a => 1
 :b => 2
 
nt = (a = 1, b = "two", c = 3.0);
vec = convert(Vector{Pair}, nt)
3-element Array{Pair{Symbol,B} where B,1}:
 :a => 1
 :b => "two"
 :c => 3.0

julia> a, b, c, d, f = 1, 1.0, 1//1, "one", (g=1,)
(1, 1.0, 1//1, "one", (g = 1,))

julia> nt = @namedtuple(a, b, c, d, e = a + b, f...)
(a = 1, b = 1.0, c = 1//1, d = "one", e = 2.0, g = 1)