# Reshape into named tuple

**URL:** <https://discourse.julialang.org/t/reshape-into-named-tuple/66474>\
**Category:** General Usage\
**Tags:** namedtuple\
**Created:** [August 16, 2021, 10:30am UTC](https://discourse.julialang.org/t/reshape-into-named-tuple/66474 "2021-08-16T10:30:53Z")\
**Posts on this page:** 5\
**Page:** 1

<div class="post-metadata">

**Author:** ![Bardo](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/bardo/32/21601_2.png) [@Bardo](https://discourse.julialang.org/u/Bardo)\
**Post date:** [August 16, 2021, 10:30am UTC](https://discourse.julialang.org/t/reshape-into-named-tuple/66474/1 "2021-08-16T10:30:53Z")

</div>

I have a vector with elements of possibly different types (but homogeneous) and the same length (\>1e8).

Example:

```julia
julia> data
3-element Vector{Any}:
 [0.7947257509914385, 0.938439282086563, 0.7825664679861779, 0.9622100725905216, 0.4505364179186473]
 [0.05038215152695846, 0.23018482446598987, 0.3575198683096761, 0.5687945898953082, 0.45331859880110126]
 [0.584780363134745, 0.7596965009119068, 0.011245396510286998, 0.9853654421407447, 0.6357566746779792]

```

and corresponding field names “:x”, “:y”, “:z”,

How to transform this into an array of named tuples (thus also type-stable),  
such that sdata[2].x == 0.938439282086563

The single element can be accessed by

```julia
data[1][2], but : combinations always yield a 5-element vector.

```

Found this similar [thread](https://discourse.julialang.org/t/type-stable-array-of-namedtuples/32743), but not sure if applicable.

---

<div class="post-metadata">

**Author:** ![fbanning](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/fbanning/32/14972_2.png) [@fbanning](https://discourse.julialang.org/u/fbanning)\
**Post date:** [August 16, 2021, 10:38am UTC](https://discourse.julialang.org/t/reshape-into-named-tuple/66474/2 "2021-08-16T10:38:28Z")

</div>

Probably not very elegant but it works:

```julia
julia> data = [rand(10), rand(10), rand(10)]
3-element Vector{Vector{Float64}}:
 [0.3045813142892593, 0.4122350061672848, 0.4735767061019649, 0.2644570924010421, 0.048985221246464095, 0.5999148629442601, 0.93
38244833695397, 0.7867455249568172, 0.28319601162576524, 0.13429265527502454]
 [0.5435428640235926, 0.876153723408583, 0.1650348423847161, 0.7847454441156623, 0.5331547615539582, 0.12257495022585352, 0.3824
331934854508, 0.4964234599222994, 0.8902713057487648, 0.6755358224731103]
 [0.19611420814764946, 0.399766030972579, 0.5676998793707868, 0.7451572134846107, 0.007488060584806666, 0.34447529370151586, 0.3
635575672925839, 0.27969842837880576, 0.3497395687887557, 0.23772803836323408]

julia> nt = collect((x=data[1][i], y=data[2][i], z=data[3][i]) for i in 1:length(data[1]))
10-element Vector{NamedTuple{(:x, :y, :z), Tuple{Float64, Float64, Float64}}}:
 (x = 0.3045813142892593, y = 0.5435428640235926, z = 0.19611420814764946)
 (x = 0.4122350061672848, y = 0.876153723408583, z = 0.399766030972579)
 (x = 0.4735767061019649, y = 0.1650348423847161, z = 0.5676998793707868)
 (x = 0.2644570924010421, y = 0.7847454441156623, z = 0.7451572134846107)
 (x = 0.048985221246464095, y = 0.5331547615539582, z = 0.007488060584806666)
 (x = 0.5999148629442601, y = 0.12257495022585352, z = 0.34447529370151586)
 (x = 0.9338244833695397, y = 0.3824331934854508, z = 0.3635575672925839)
 (x = 0.7867455249568172, y = 0.4964234599222994, z = 0.27969842837880576)
 (x = 0.28319601162576524, y = 0.8902713057487648, z = 0.3497395687887557)
 (x = 0.13429265527502454, y = 0.6755358224731103, z = 0.23772803836323408)
```

---

<div class="post-metadata">

**Author:** ![robsmith11](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/robsmith11/32/29641_2.png) [@robsmith11](https://discourse.julialang.org/u/robsmith11)\
**Post date:** [August 16, 2021, 10:43am UTC](https://discourse.julialang.org/t/reshape-into-named-tuple/66474/3 "2021-08-16T10:43:07Z")

</div>

```julia
julia> data = Any[rand(5), rand(Int8, 5), rand(Bool, 5)]
3-element Vector{Any}:
 [0.3005737233263839, 0.9001020036533961, 0.23278850839511744, 0.28874192844445024, 0.5812484239516024]
 Int8[78, 45, 82, -28, 106]
 Bool[0, 1, 1, 0, 1]

julia> nt = (; zip([:x; :y; :z], data)...)
(x = [0.3005737233263839, 0.9001020036533961, 0.23278850839511744, 0.28874192844445024, 0.5812484239516024], y = Int8[78, 45, 82, -28, 106], z = Bool[0, 1, 1, 0, 1])

julia> typeof(nt)
NamedTuple{(:x, :y, :z), Tuple{Vector{Float64}, Vector{Int8}, Vector{Bool}}}

julia> nt.y[3]
82

```

EDIT: Actually I think you wanted this:

```julia
julia> NamedTuple.(zip.(Ref([:x; :y; :z]), zip(data...)))
5-element Vector{NamedTuple{(:x, :y, :z), Tuple{Float64, Int8, Bool}}}:
 (x = 0.3005737233263839, y = 78, z = 0)
 (x = 0.9001020036533961, y = 45, z = 1)
 (x = 0.23278850839511744, y = 82, z = 1)
 (x = 0.28874192844445024, y = -28, z = 0)
 (x = 0.5812484239516024, y = 106, z = 1)

```

---

<div class="post-metadata">

**Author:** ![Bardo](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/bardo/32/21601_2.png) [@Bardo](https://discourse.julialang.org/u/Bardo)\
**Post date:** [August 16, 2021, 10:48am UTC](https://discourse.julialang.org/t/reshape-into-named-tuple/66474/4 "2021-08-16T10:48:06Z")

</div>

Thanks for the start!

Would need to extend it to process the fieldnames (number and values read from IO).  
Maybe there is no really elegant solution, its part of the “array of struct” deficiency: I can store/transmit/load homogeneous streams but in the end have to re-sort them again. Not to be recommended for large number of structs.

Could we think of other data structures than named tuples here?  
Allowing incremental built-up, not requiring copying and data on the heap etc.

---

<div class="post-metadata">

**Author:** ![Bardo](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/bardo/32/21601_2.png) [@Bardo](https://discourse.julialang.org/u/Bardo)\
**Post date:** [August 16, 2021, 10:52am UTC](https://discourse.julialang.org/t/reshape-into-named-tuple/66474/5 "2021-08-16T10:52:18Z")

</div>

Exactly, thanks a lot!