# Passing an array defined inside a function out of the function

**URL:** <https://discourse.julialang.org/t/passing-an-array-defined-inside-a-function-out-of-the-function/2836>\
**Category:** New to Julia\
**Created:** [March 23, 2017, 1:32pm UTC](https://discourse.julialang.org/t/passing-an-array-defined-inside-a-function-out-of-the-function/2836 "2017-03-23T13:32:53Z")\
**Posts on this page:** 7\
**Page:** 1

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**Author:** ![Agent-Fitz](https://avatars.discourse-cdn.com/v4/letter/a/9fc348/32.png) [@Agent-Fitz](https://discourse.julialang.org/u/Agent-Fitz)\
**Post date:** [March 23, 2017, 1:32pm UTC](https://discourse.julialang.org/t/passing-an-array-defined-inside-a-function-out-of-the-function/2836/1 "2017-03-23T13:32:53Z")

</div>

Dear Julia community,

I’m having what it probably a simple problem but after a lot of googling and trial and error I’m still at the “error” stage so I thought I’d ask for help 🙂

I have a function that fills an array:

```julia
function UnscaleY(Factor::Float64, YList::Array{Float64}, b::Array{Float64})
 CarteY=zeros(YList)
 n=size(YList,1)
 for i in 1:n
  CarteY=Factor*(YList[i]*b[1] + YList[i]*b[2] + YList[i]*b[3])
 end
 return CarteY
end

```

I would like my return array, CarteY, to be accessible outside the scope of the function so that I can do some more operations with it and then save the result to a file. But when I try that, for example:

```julia
Test=zeros(CarteY, 1)
AnotherArrayY=[Test CarteY]
writedlm("another array.txt", AnotherArray)

```

I get a dimensions mismatch error. Test and CarteY should have the same number of rows (for this case, they are both 54x1 column vectors) and I have verified this in the REPL. I’m not sure where my error is.

Any help is greatly appreciated!

---

<div class="post-metadata">

**Author:** ![dpsanders](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/dpsanders/32/3573_2.png) [@dpsanders](https://discourse.julialang.org/u/dpsanders)\
**Post date:** [March 23, 2017, 1:36pm UTC](https://discourse.julialang.org/t/passing-an-array-defined-inside-a-function-out-of-the-function/2836/2 "2017-03-23T13:36:49Z")

</div>

Please include full working code and data.  
In this case, you did not show how you called the function UnscaleY.

You probably need to assign CarteY = UnscaleY(something)

---

<div class="post-metadata">

**Author:** ![Agent-Fitz](https://avatars.discourse-cdn.com/v4/letter/a/9fc348/32.png) [@Agent-Fitz](https://discourse.julialang.org/u/Agent-Fitz)\
**Post date:** [March 23, 2017, 1:38pm UTC](https://discourse.julialang.org/t/passing-an-array-defined-inside-a-function-out-of-the-function/2836/3 "2017-03-23T13:38:51Z")

</div>

Hi @dpsanders, here is how I call the function:

```julia
TestY=UnscaleY(Factor, YList, b)

```

---

<div class="post-metadata">

**Author:** ![dpsanders](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/dpsanders/32/3573_2.png) [@dpsanders](https://discourse.julialang.org/u/dpsanders)\
**Post date:** [March 23, 2017, 1:40pm UTC](https://discourse.julialang.org/t/passing-an-array-defined-inside-a-function-out-of-the-function/2836/4 "2017-03-23T13:40:53Z")

</div>

Please provide your complete code snippet that we can run including (fake) data.

---

<div class="post-metadata">

**Author:** ![Agent-Fitz](https://avatars.discourse-cdn.com/v4/letter/a/9fc348/32.png) [@Agent-Fitz](https://discourse.julialang.org/u/Agent-Fitz)\
**Post date:** [March 23, 2017, 1:44pm UTC](https://discourse.julialang.org/t/passing-an-array-defined-inside-a-function-out-of-the-function/2836/5 "2017-03-23T13:44:42Z")

</div>

Sure thing,

```julia
Factor=1.0

 LatticeVectors=readdlm("lattice-vectors")
 a=LatticeVectors[1:1,:]
 b=LatticeVectors[2:2,:]
 c=LatticeVectors[3:3,:]
 println("...the lattice vectors are:")
 println("a=", a)
 println("b=", b)
 println("c=", c)

DirectList=readdlm("direct-list")
XList=DirectList[1:54,1]
YList=DirectList[1:54,2]
ZList=DirectList[1:54, 3]

function UnscaleX(Factor::Float64, XList::Array{Float64}, a::Array{Float64})
 CarteX=zeros(XList)
 n=size(XList,1)
 for i in 1:n
  CarteX[i]= Factor*(XList[i]*a[1] + XList[i]*a[2] + XList[i]*a[3])
 end
 CarteX
end

function UnscaleY(Factor::Float64, YList::Array{Float64}, b::Array{Float64})
 CarteY=zeros(YList)
 n=size(YList,1)
 for i in 1:n
  CarteY=Factor*(YList[i]*b[1] + YList[i]*b[2] + YList[i]*b[3])
 end
 return CarteY
end

function UnscaleZ(Factor::Float64, ZList::Array{Float64}, c::Array{Float64})
 CarteZ=zeros(ZList)
 n=size(ZList,1)
 for i in 1:n
  CarteZ=CartesianZList=Factor*(ZList[i]*c[1] + ZList[i]*c[2] + ZList[i]*c[3])
 end
 return CarteZ
end

TestX=zeros(XList)
TestY=zeros(YList)
TestZ=zeros(ZList)
TestX=UnscaleX(Factor, XList, a)
TestY=UnscaleY(Factor, YList, b)
TestY=UnscaleZ(Factor, ZList, c)

Cartesian=zeros(54, 3)
Cartesian=[TestX TestY TestZ]
println(Cartesian)
println("...Cartesian coordinates are being saved to the file: cartesian-coords.txt")
writedlm("cartesian-coords.txt", Cartesian)

```

Files with fake data:  
File lattice-vectors contains the following:

```julia
 15.2259346732869041 0.0050373306177292 0.0186555174857414
-7.0913762758806689 13.4745115715249604 0.0182226035629158
 -7.0916724110859466 11.7516324991570080 6.5928931085496609

```

File direct-list contains:

```julia
  0.7482245082990034 0.3534019561877609 0.1812378289473642
  0.6178686864118543 0.1681233715252839 0.0821353813181317
  0.4357333985898882 0.9695266986682127 0.8683503946494281
  0.3242964642812215 0.8076126796414442 0.7941651238854253
  0.1812417570426143 0.7482124708854798 0.3533874975116351
  0.0821432447687275 0.6178660181570326 0.1681074617961152
  0.8683593838356138 0.4357342720578281 0.9695141008383492
  0.7941780484555921 0.3243099013687005 0.8075985077022094
  0.3533875088260943 0.1812464919612361 0.7482169792073099
  0.1681051383648486 0.0821450806675383 0.6178521899197107
  0.9695102304529243 0.8683608555517192 0.4357129975650504
  0.8075933403174808 0.7941779831051727 0.3242669341483143
  0.2518079787588328 0.6466360641850607 0.8187536189884783
  0.3821700051047205 0.8319173244530188 0.9178577649264432
  0.5643066165282937 0.0305157504412312 0.1316440805260589
  0.6757386225074868 0.1924286807211093 0.2058276349695207
  0.8187763498964314 0.2518389094923041 0.6466177058035906
  0.9178731599448806 0.3821930874036329 0.8318978053304958
  0.1316586451011760 0.5643317802194968 0.0304930862752822
  0.2058389019103447 0.6757504398400337 0.1924080097315123
  0.6466207033339431 0.8187848140403626 0.2517927628100531
  0.8318961348815688 0.9178750595770820 0.3821416949918647
  0.0304930169122549 0.1316611152535211 0.5642822311429468
  0.1924063837065296 0.2058395520413121 0.6757204995273713
  0.1858282736115658 0.6553591972564562 0.6322799537724728
  0.6322933931195204 0.1858446243288009 0.6553487757883374
  0.6553404514988551 0.6322932698972672 0.1857950510331017
  0.8141950235177683 0.3446830202774450 0.3677091014705928
  0.3677211439898948 0.8142100503972600 0.3446597515296888
  0.3446593118364114 0.3677221543508475 0.8141866785824847
  0.6981865926942720 0.3333917203738143 0.0692480301421015
  0.9043833218257868 0.5264829859982945 0.3701530491344796
  0.3662307749504640 0.9306573408865069 0.7366377267545515
  0.0692521847562757 0.6981793081050421 0.3333827932116585
  0.3701539145218680 0.9043621240139327 0.5264629248805210
  0.7366440236451102 0.3662253009791751 0.9306487282664943
  0.3333867003273195 0.0692587353055780 0.6981855480007444
  0.5264653972743839 0.3701612556937298 0.9043783722804863
  0.9306492271069859 0.7366501298752793 0.3662224046151440
  0.3018462195926945 0.6666441173467359 0.9307425348348507
  0.0956399187615062 0.4735534469652757 0.6298350111775736
  0.6338065183530964 0.0693844350988777 0.2633559683332034
  0.9307653118267606 0.3018601266864653 0.6666226325414922
  0.6298659855286579 0.0956917531533225 0.4735391504587828
  0.2633719239128310 0.6338446853007450 0.0693546518174230
  0.6666289119963787 0.9307756483485854 0.3018102551604652
  0.4735433006407601 0.6298785805458186 0.0956584473233547
  0.0693631109866678 0.2633795254480514 0.6337875662267405
  0.5197348673738973 0.1144740833773222 0.7873118502351895
  0.7873126286326132 0.5197330899686363 0.1144702234295533
  0.1144777633769872 0.7873265496067330 0.5197331478490889
  0.4802955162322206 0.8855815579437910 0.2126891024534877
  0.2127046167967178 0.4803123212502428 0.8855431458900669
  0.8855577438543734 0.2127220547985894 0.4802804552218186

```

---

<div class="post-metadata">

**Author:** ![kristoffer.carlsson](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/kristoffer.carlsson/32/22_2.png) [@kristoffer.carlsson](https://discourse.julialang.org/u/kristoffer.carlsson)\
**Post date:** [March 23, 2017, 1:54pm UTC](https://discourse.julialang.org/t/passing-an-array-defined-inside-a-function-out-of-the-function/2836/6 "2017-03-23T13:54:13Z")

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```julia
 for i in 1:n
    CarteY=Factor*(YList[i]*b[1] + YList[i]*b[2] + YList[i]*b[3])
 end

```

looks weird. You are just overwriting `CarteY` (with a scalar) in every iteration. Did you want (note the `[i]` on `CarteY`:

```julia
 for i in 1:n
    CarteY[i]=Factor*(YList[i]*b[1] + YList[i]*b[2] + YList[i]*b[3])
 end

```

?

---

<div class="post-metadata">

**Author:** ![Agent-Fitz](https://avatars.discourse-cdn.com/v4/letter/a/9fc348/32.png) [@Agent-Fitz](https://discourse.julialang.org/u/Agent-Fitz)\
**Post date:** [March 23, 2017, 2:09pm UTC](https://discourse.julialang.org/t/passing-an-array-defined-inside-a-function-out-of-the-function/2836/8 "2017-03-23T14:09:11Z")

</div>

Thank you! I’ve fixed that and another problem that I found. I’ll put the solution to that in case someone else has a similar problem:

The writing to file section I had initially just printed a long row vector list to the file. To print in [x y z] format, I’ve changed the last bit of code to this:

```julia
writedlm("coords.txt", [TestX TestY TestZ], '\t')

```