# Latest

**URL:** https://discourse.julialang.org/latest.md?page=1904

[Latest](https://discourse.julialang.org/latest.md) · [Categories](https://discourse.julialang.org/categories.md) · [Tags](https://discourse.julialang.org/tags.md)

**Page:** 1905

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## [How can I draw 2 series in the same chart](https://discourse.julialang.org/t/how-can-i-draw-2-series-in-the-same-chart/29736)

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**Author:** [@hasanOryx](https://discourse.julialang.org/u/hasanOryx)\
**Replies:** 11\
**Last updated:** [October 10, 2019, 9:32pm UTC](https://discourse.julialang.org/t/how-can-i-draw-2-series-in-the-same-chart/29736 "2019-10-10T21:32:41Z")

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I was able to plt the first series as: using Gadfly history = \[30,21,29,31,40,48,53,47,37,39,31,29,17,9,20,24,27,35,41,38, 27,31,27,26,21,13,21,18,33,35,40,36,22,24,21,20,17,14,17,19, 26,29,40,31,20…

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## [Problems with IJulia](https://discourse.julialang.org/t/problems-with-ijulia/29617)

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**Author:** [@alewolf](https://discourse.julialang.org/u/alewolf)\
**Replies:** 16\
**Last updated:** [October 10, 2019, 9:10pm UTC](https://discourse.julialang.org/t/problems-with-ijulia/29617 "2019-10-10T21:10:33Z")

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Hi I am using Julia 1.2. I have a pre-installed version of anaconda - So before building IJulia I do the following ENV\["PYTHON"\]="C:\\\\ProgramData\\\\Anaconda3\\\\python" ENV\["JUPYTER"\]="C:\\\\ProgramData\\\\Anaconda3\\\\Scripts…

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## [How can I get the chunks of a given array](https://discourse.julialang.org/t/how-can-i-get-the-chunks-of-a-given-array/29737)

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**Author:** [@hasanOryx](https://discourse.julialang.org/u/hasanOryx)\
**Replies:** 7\
**Last updated:** [October 10, 2019, 9:07pm UTC](https://discourse.julialang.org/t/how-can-i-get-the-chunks-of-a-given-array/29737 "2019-10-10T21:07:35Z")

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I’ve a series of 60 elements: series = \[30,21,29,31,40,48,53,47,37,39,31,29,17,9,20,24,27,35,41,38, 27,31,27,26,21,13,21,18,33,35,40,36,22,24,21,20,17,14,17,19, 26,29,40,31,20,24,18,26,17,9,17,21,28,…

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## [Warning about Mamba and JuMP](https://discourse.julialang.org/t/warning-about-mamba-and-jump/29743)

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**Author:** [@marouane](https://discourse.julialang.org/u/marouane)\
**Replies:** 3\
**Last updated:** [October 10, 2019, 8:16pm UTC](https://discourse.julialang.org/t/warning-about-mamba-and-jump/29743 "2019-10-10T20:16:58Z")

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i have a code where i’m using Mambaand JuMPand when i run the code, i get a warning like this: WARNING: both Mamba and JuMP export "Model"; uses of it in module QuantumRelay must be qualified Therefore i get an Error: …

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## [Parametric Types with struct constructors](https://discourse.julialang.org/t/parametric-types-with-struct-constructors/29742)

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**Author:** [@sstadick](https://discourse.julialang.org/u/sstadick)\
**Replies:** 3\
**Last updated:** [October 10, 2019, 7:59pm UTC](https://discourse.julialang.org/t/parametric-types-with-struct-constructors/29742 "2019-10-10T19:59:21Z")

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Hello! I’m new to julia and trying to get a grasp on parametric types / use it like a geric type. Here’s the code: struct Interval{T} start::Int stop::Int val::T end struct ScAIList{T} interval\_list:…

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## [ForwardDiff on keyword argument?](https://discourse.julialang.org/t/forwarddiff-on-keyword-argument/29733)

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**Author:** [@BLI](https://discourse.julialang.org/u/BLI)\
**Replies:** 3\
**Last updated:** [October 10, 2019, 7:29pm UTC](https://discourse.julialang.org/t/forwarddiff-on-keyword-argument/29733 "2019-10-10T19:29:50Z")

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I have a function with parameters as a keyword argument, say: f(x;p = \[1,2,1\]) = p\[1\]\*x^2 + p\[2\]\*x + p\[3\] How do I compute the gradient g(x,p) = \\frac{\\partial f(x;p)}{\\partial p}?

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## [Inferring return type of a method](https://discourse.julialang.org/t/inferring-return-type-of-a-method/29698)

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**Author:** [@sw72](https://discourse.julialang.org/u/sw72)\
**Replies:** 3\
**Last updated:** [October 10, 2019, 6:47pm UTC](https://discourse.julialang.org/t/inferring-return-type-of-a-method/29698 "2019-10-10T18:47:25Z")

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There is probably a simpler example but this is the essence of my problem: abstract type Abstract end struct Concrete1 \<: Abstract end struct Concrete2 \<: Abstract end struct Thing a::Abstract end (::Concrete1)(x)= 1+x…

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## [@enum is slow?](https://discourse.julialang.org/t/enum-is-slow/29018)

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**Author:** [@tuckermcclure](https://discourse.julialang.org/u/tuckermcclure)\
**Replies:** 4\
**Last updated:** [October 10, 2019, 6:26pm UTC](https://discourse.julialang.org/t/enum-is-slow/29018 "2019-10-10T18:26:15Z")

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We have a project with 67 different enum types, each with say a dozen enumerated values. Each type and value is exported. Simply including this file takes about 15s, which is a surprisingly long time. When I comment out …

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## [ANN: Juno 0.11](https://discourse.julialang.org/t/ann-juno-0-11/29644)

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**Author:** [@pfitzseb](https://discourse.julialang.org/u/pfitzseb)\
**Replies:** 32\
**Last updated:** [October 10, 2019, 4:36pm UTC](https://discourse.julialang.org/t/ann-juno-0-11/29644 "2019-10-10T16:36:34Z")

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Hey folks, Juno 0.11 is out and brings you lots of bugfixes, improvements, and some exciting new features. As always, thanks to @aviatesk for his stellar work! Release notes New features Added a Juno: Work in Folder c…

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## [ARFIMA.jl - proof of concept of Julia's multiple dispatch](https://discourse.julialang.org/t/arfima-jl-proof-of-concept-of-julias-multiple-dispatch/29726)

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**Author:** [@Datseris](https://discourse.julialang.org/u/Datseris)\
**Replies:** 2\
**Last updated:** [October 10, 2019, 4:33pm UTC](https://discourse.julialang.org/t/arfima-jl-proof-of-concept-of-julias-multiple-dispatch/29726 "2019-10-10T16:33:42Z")

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Hello all, ARFIMA is a process that generates stochastic timeseries. It is a generalization of various other known processes, like ARMA, ARIMA, AR, etc… for a long time I needed to write some code to simulate ARFIMA pr…

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## [Generalised CUDA/CPU](https://discourse.julialang.org/t/generalised-cuda-cpu/29633)

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**Author:** [@Raf](https://discourse.julialang.org/u/Raf)\
**Replies:** 10\
**Last updated:** [October 10, 2019, 2:53pm UTC](https://discourse.julialang.org/t/generalised-cuda-cpu/29633 "2019-10-10T14:53:55Z")

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So this is the old question of using exponents and similar in code that runs on Cuda. I’m wondering what solutions are people using in late 2019. There are answers like this: https://github.com/JuliaGPU/CuArrays.jl/issu…

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## [Understanding specialization and parametric types](https://discourse.julialang.org/t/understanding-specialization-and-parametric-types/29680)

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**Author:** [@rapus95](https://discourse.julialang.org/u/rapus95)\
**Replies:** 9\
**Last updated:** [October 10, 2019, 1:38pm UTC](https://discourse.julialang.org/t/understanding-specialization-and-parametric-types/29680 "2019-10-10T13:38:02Z")

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EDITSTART The following link @Tamas\_Papp posted in the solution might help everyone with similar questions. https://docs.julialang.org/en/v1/manual/methods/#Design-Patterns-with-Parametric-Methods-1 EDITEND Right now…

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## [\`ELOOP\` when \`walkdir\`](https://discourse.julialang.org/t/eloop-when-walkdir/29679)

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**Author:** [@innerlee](https://discourse.julialang.org/u/innerlee)\
**Replies:** 1\
**Last updated:** [October 10, 2019, 12:34pm UTC](https://discourse.julialang.org/t/eloop-when-walkdir/29679 "2019-10-10T12:34:47Z")

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I modified the source code of walkdir a little bit to skip some irrelevant dirs. However, the code produces ELOOP error about when 2000 directories are processed. I do not understand the error. Is it because there are to…

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## [Unable to save pane layout](https://discourse.julialang.org/t/unable-to-save-pane-layout/27814)

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**Author:** [@Egwene\_al\_Vere](https://discourse.julialang.org/u/Egwene_al_Vere)\
**Replies:** 4\
**Last updated:** [October 10, 2019, 12:16pm UTC](https://discourse.julialang.org/t/unable-to-save-pane-layout/27814 "2019-10-10T12:16:48Z")

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After a recent update, if I now move around/resize some panes (like REPL, Plot, workspace), after I quit atom and reopen the file, the layout would be lost; I tried unticking the option “open default panes on startup” bu…

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## [Copy of immutable with multiple fields changed](https://discourse.julialang.org/t/copy-of-immutable-with-multiple-fields-changed/29719)

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**Author:** [@Tamas\_Papp](https://discourse.julialang.org/u/Tamas_Papp)\
**Replies:** 3\
**Last updated:** [October 10, 2019, 11:58am UTC](https://discourse.julialang.org/t/copy-of-immutable-with-multiple-fields-changed/29719 "2019-10-10T11:58:57Z")

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Is there a package which makes it convenient to get a copy of an (immutable) struct with new values for some fields? I am aware of Setfield, but my understanding (see below) is that it requires nesting to do this. using…

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## [AssertionError](https://discourse.julialang.org/t/assertionerror/29690)

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**Author:** [@marouane](https://discourse.julialang.org/u/marouane)\
**Replies:** 10\
**Last updated:** [October 10, 2019, 9:43am UTC](https://discourse.julialang.org/t/assertionerror/29690 "2019-10-10T09:43:45Z")

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i have this piece of code: MAT=\[1 0;0 2\] n=count(!iszero,MAT) n0=MAT\[1:n\] @assert n0 == ones(n) i ran into an unexpected assertion error for this part, apparently @assertdidn’t evaluate the assert code line for some re…

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## [Congratulations to Alan Edelman](https://discourse.julialang.org/t/congratulations-to-alan-edelman/29642)

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**Author:** [@PetrKryslUCSD](https://discourse.julialang.org/u/PetrKryslUCSD)\
**Replies:** 1\
**Last updated:** [October 10, 2019, 8:56am UTC](https://discourse.julialang.org/t/congratulations-to-alan-edelman/29642 "2019-10-10T08:56:44Z")

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Congratulations to Alan Edelman of MIT, one of the co-creators of Julia (I didn’t have to say that, did I?). He was recognized with Prestigious 2019 IEEE Computer Society Sidney Fernbach Award. Among other accomplishmen…

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## [Performance comparison with C++](https://discourse.julialang.org/t/performance-comparison-with-c/29682)

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**Author:** [@gcalderone](https://discourse.julialang.org/u/gcalderone)\
**Replies:** 8\
**Last updated:** [October 10, 2019, 8:39am UTC](https://discourse.julialang.org/t/performance-comparison-with-c/29682 "2019-10-10T08:39:40Z")

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I found a very simple task where the Julia performances are unexpectedly and significantly worse than C++. The core function to be benchmarked is as follows: function subr!(d1, nx, ny, d2) for iy in 1:ny fo…

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## [Plot directly to file](https://discourse.julialang.org/t/plot-directly-to-file/29716)

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**Author:** [@HenrikM](https://discourse.julialang.org/u/HenrikM)\
**Replies:** 2\
**Last updated:** [October 10, 2019, 8:37am UTC](https://discourse.julialang.org/t/plot-directly-to-file/29716 "2019-10-10T08:37:58Z")

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I am preparing my Julia code as scripts that will run on a remote compute server. When I run the example locally, as julia --project test1.jl, it produces a file sine.pdf. When I run it remotely, it gives the following e…

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## [Abstract constructor](https://discourse.julialang.org/t/abstract-constructor/29700)

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**Author:** [@jlapeyre](https://discourse.julialang.org/u/jlapeyre)\
**Replies:** 1\
**Last updated:** [October 10, 2019, 5:55am UTC](https://discourse.julialang.org/t/abstract-constructor/29700 "2019-10-10T05:55:55Z")

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I have a set of types that are related, e.g. by composition, but also logically (eg one can be converted to another). I have a parallel set of types that satisfy the same relations. I’d like to put as much as possible …

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## [Consistent 2x Slowdown with v1.2](https://discourse.julialang.org/t/consistent-2x-slowdown-with-v1-2/29535)

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**Author:** [@swishmas](https://discourse.julialang.org/u/swishmas)\
**Replies:** 6\
**Last updated:** [October 10, 2019, 5:55am UTC](https://discourse.julialang.org/t/consistent-2x-slowdown-with-v1-2/29535 "2019-10-10T05:55:54Z")

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Hi there, I have been working on some code (~4,000 lines) for a while, and I was excited about the upcoming changes to the parallelization in v1.3. I felt I had very efficient code on v1.1(.1), but when I run the code …

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## [Lazy and eager API design](https://discourse.julialang.org/t/lazy-and-eager-api-design/22398)

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**Author:** [@Tamas\_Papp](https://discourse.julialang.org/u/Tamas_Papp)\
**Replies:** 6\
**Last updated:** [October 10, 2019, 5:27am UTC](https://discourse.julialang.org/t/lazy-and-eager-api-design/22398 "2019-10-10T05:27:45Z")

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This is a somewhat general API interface design question and I am still wondering about the idiomatic “Julian” way of formulating it, so I thought I would ask here. Suppose I have a vocabulary of verbs f, g, h, which op…

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## [Test a function modifies argument](https://discourse.julialang.org/t/test-a-function-modifies-argument/29688)

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**Author:** [@squirrel](https://discourse.julialang.org/u/squirrel)\
**Replies:** 5\
**Last updated:** [October 10, 2019, 5:30am UTC](https://discourse.julialang.org/t/test-a-function-modifies-argument/29688 "2019-10-10T05:30:14Z")

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How should I write a @testset to verify that a function modifies its argument? For example, here is a function that is passed a vector (of Rationals) v and a row index row: function divideBelow!(v, row) f = v\[row\]…

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## [Improving performance of a nested for loop](https://discourse.julialang.org/t/improving-performance-of-a-nested-for-loop/29705)

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**Author:** [@jessecm](https://discourse.julialang.org/u/jessecm)\
**Replies:** 14\
**Last updated:** [October 10, 2019, 5:14am UTC](https://discourse.julialang.org/t/improving-performance-of-a-nested-for-loop/29705 "2019-10-10T05:14:31Z")

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Hi, sorry this is kind of a beginner/performance question. I want to generate a matrix of all of the pairwise differences among the rows of a matrix. The code below works, but gets slow as matrices get large (e.g., 1000 …

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## [Unicode \\epsilon\\\_y](https://discourse.julialang.org/t/unicode-epsilon-y/29429)

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**Author:** [@Rajesh\_Talluri](https://discourse.julialang.org/u/Rajesh_Talluri)\
**Replies:** 33\
**Last updated:** [October 10, 2019, 4:45am UTC](https://discourse.julialang.org/t/unicode-epsilon-y/29429 "2019-10-10T04:45:42Z")

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Hi, I am trying to define a variable \\epsilon\\\_y. And it does not autocomplete. \\epsilon\\\_x works but \\epsilon\\\_y and \\epsilon\\\_z do not work. I checked the Unicode Input page in Julia docs and \\\_y is not defined. Co…

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## [Printing to string from stream](https://discourse.julialang.org/t/printing-to-string-from-stream/29689)

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**Author:** [@Rajesh\_Talluri](https://discourse.julialang.org/u/Rajesh_Talluri)\
**Replies:** 1\
**Last updated:** [October 10, 2019, 2:07am UTC](https://discourse.julialang.org/t/printing-to-string-from-stream/29689 "2019-10-10T02:07:05Z")

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Hi, I am trying to get the output of a stream into a string. For example the highlight function outputs the result to an IO object, so I can open a file and write to it. I can also get it printed using stdout. However…

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## [\[ANN\] Fread.jl - read CSVs faster with the help of R's {data.table}](https://discourse.julialang.org/t/ann-fread-jl-read-csvs-faster-with-the-help-of-rs-data-table/29681)

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**Author:** [@xiaodai](https://discourse.julialang.org/u/xiaodai)\
**Replies:** 6\
**Last updated:** [October 9, 2019, 9:35pm UTC](https://discourse.julialang.org/t/ann-fread-jl-read-csvs-faster-with-the-help-of-rs-data-table/29681 "2019-10-09T21:35:31Z")

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Update You should really be using CSV.jl because it performs quite well. I only use Fread.jl for converting data from parquet to feature etc now and not for reading CSVs as CSV.jl is actually really good. Original cont…

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## [Help required for drawing a chart](https://discourse.julialang.org/t/help-required-for-drawing-a-chart/29694)

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**Author:** [@hasanOryx](https://discourse.julialang.org/u/hasanOryx)\
**Replies:** 6\
**Last updated:** [October 9, 2019, 9:17pm UTC](https://discourse.julialang.org/t/help-required-for-drawing-a-chart/29694 "2019-10-09T21:17:34Z")

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I’ve the below table of data: 2×7 DataFrame │ Row │ Customer │ M0 │ M1 │ M2 │ M3 │ ... │ Mn │ │ │ String │ Int64 │ Int64 │ Int64 │ Int64 │ Int64 │ Int64 │ ├─────┼──────────┼─────────┼───…

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## [Why is @enum 0-based?](https://discourse.julialang.org/t/why-is-enum-0-based/12722)

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**Author:** [@gdkrmr](https://discourse.julialang.org/u/gdkrmr)\
**Replies:** 6\
**Last updated:** [October 9, 2019, 8:50pm UTC](https://discourse.julialang.org/t/why-is-enum-0-based/12722 "2019-10-09T20:50:40Z")

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Arrays in Julia are 1-based, so why are Enums 0-based? julia\> Base.Enums.@enum ABC begin A B C end julia\> ABC(0) A::ABC = 0

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## [Filtering and Grouping DataFrame](https://discourse.julialang.org/t/filtering-and-grouping-dataframe/29691)

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**Author:** [@hasanOryx](https://discourse.julialang.org/u/hasanOryx)\
**Replies:** 4\
**Last updated:** [October 9, 2019, 8:03pm UTC](https://discourse.julialang.org/t/filtering-and-grouping-dataframe/29691 "2019-10-09T20:03:37Z")

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I’ve a csv file of the following: 1- Customer name 2- Customer location 3- Deliveries over last 60 months, so n in the table below is 60 sometimes more I read the data as: using CSV, Query, DataFramesMeta, DataFrame…

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