# Latest

**URL:** https://discourse.julialang.org/latest.md?page=1450

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

**Page:** 1451

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## [Dividing a number by the number of days between dates](https://discourse.julialang.org/t/dividing-a-number-by-the-number-of-days-between-dates/57728)

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**Author:** [@Nash](https://discourse.julialang.org/u/Nash)\
**Replies:** 2\
**Last updated:** [March 22, 2021, 5:12pm UTC](https://discourse.julialang.org/t/dividing-a-number-by-the-number-of-days-between-dates/57728 "2021-03-22T17:12:26Z")

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I am working with dates in the format m-d-yyyy for the purpose of computing the average stock return between two such dates. But when it comes to dividing the total return by the number of days between the two dates, I h…

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## [Tuples with mutable entries?](https://discourse.julialang.org/t/tuples-with-mutable-entries/57734)

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**Author:** [@JuliusAurelius](https://discourse.julialang.org/u/JuliusAurelius)\
**Replies:** 1\
**Last updated:** [March 22, 2021, 4:40pm UTC](https://discourse.julialang.org/t/tuples-with-mutable-entries/57734 "2021-03-22T16:40:17Z")

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Hey, I just read through this article by Julius Krumbiegel where he explains the differences of Vectors and Tuples and their memory usage. Mainly the advantage of the compiler knowing that the size of the referenced obje…

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## [How to set up Julia in a machine isolated from internet?](https://discourse.julialang.org/t/how-to-set-up-julia-in-a-machine-isolated-from-internet/57715)

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**Author:** [@hpw](https://discourse.julialang.org/u/hpw)\
**Replies:** 3\
**Last updated:** [March 22, 2021, 4:30pm UTC](https://discourse.julialang.org/t/how-to-set-up-julia-in-a-machine-isolated-from-internet/57715 "2021-03-22T16:30:22Z")

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I am really having fun in using Julia for my hobby project at home. Especially, the multiple dispatch feature which I have once read about in books of CL. And I would like to use it for my work, which has machines isol…

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## [\[ANN\] NormalHermiteSplines.jl v.0.4.0](https://discourse.julialang.org/t/ann-normalhermitesplines-jl-v-0-4-0/57554)

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**Author:** [@igorkohan](https://discourse.julialang.org/u/igorkohan)\
**Replies:** 8\
**Last updated:** [March 22, 2021, 4:18pm UTC](https://discourse.julialang.org/t/ann-normalhermitesplines-jl-v-0-4-0/57554 "2021-03-22T16:18:49Z")

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Multivariate Normal Hermite-Birkhoff Interpolating Splines in Julia This announces the v0.4.0 release of NormalHermiteSplines.jl package that implements the normal splines method for solving the following interpolation …

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## [Optimizing an ODEProblem with Threads?](https://discourse.julialang.org/t/optimizing-an-odeproblem-with-threads/57732)

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**Author:** [@cmarcotte](https://discourse.julialang.org/u/cmarcotte)\
**Replies:** 1\
**Last updated:** [March 22, 2021, 4:14pm UTC](https://discourse.julialang.org/t/optimizing-an-odeproblem-with-threads/57732 "2021-03-22T16:14:58Z")

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I have a sizable (402) ODE system which comes from the discretization of a parabolic PDE (Beeler-Reuter model in 1D); in the past I used ModelingToolkit to optimize my poorly written in-place function by evaluating it ov…

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## [Xticks in month format](https://discourse.julialang.org/t/xticks-in-month-format/57721)

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**Author:** [@dires](https://discourse.julialang.org/u/dires)\
**Replies:** 2\
**Last updated:** [March 22, 2021, 3:51pm UTC](https://discourse.julialang.org/t/xticks-in-month-format/57721 "2021-03-22T15:51:39Z")

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Hi I am working on a yearly planning model in hourly resolution, and I want to plot the result with the X-axis in months, not in hours. how can I do my plots in Gadfly?

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## [Julia v1.6.0-rc3 is now available](https://discourse.julialang.org/t/julia-v1-6-0-rc3-is-now-available/57441)

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**Author:** [@ararslan](https://discourse.julialang.org/u/ararslan)\
**Replies:** 3\
**Last updated:** [March 22, 2021, 3:24pm UTC](https://discourse.julialang.org/t/julia-v1-6-0-rc3-is-now-available/57441 "2021-03-22T15:24:21Z")

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The Julia developers are pleased to announce that the third release candidate for Julia v1.6.0 is now available. You can download binaries at https://julialang.org/downloads in the “upcoming release” section for macOS, …

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## [Save log in vscode windows](https://discourse.julialang.org/t/save-log-in-vscode-windows/57726)

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**Author:** [@virgile-baudrot](https://discourse.julialang.org/u/virgile-baudrot)\
**Replies:** 0\
**Last updated:** [March 22, 2021, 3:20pm UTC](https://discourse.julialang.org/t/save-log-in-vscode-windows/57726 "2021-03-22T15:20:07Z")

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Is there a simple way to save the REPL logs (in vscode under windows) or better to see a lot more lines (without changing the font-size)? It’s to see the first lines of a bugs, but the red lines quickly disappear in a f…

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## [Newbie question about HamiltonianProblem](https://discourse.julialang.org/t/newbie-question-about-hamiltonianproblem/57492)

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**Author:** [@manroygood](https://discourse.julialang.org/u/manroygood)\
**Replies:** 10\
**Last updated:** [March 22, 2021, 3:15pm UTC](https://discourse.julialang.org/t/newbie-question-about-hamiltonianproblem/57492 "2021-03-22T15:15:05Z")

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I’m trying to teach myself Julia by using it to solve some differential equations i need solved. I’ve been looking at this example I’d like to plot the Hamiltonian (or any other function of the variables) as a function …

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## [\[differentialequations.jl\] stuck at initial value when using function](https://discourse.julialang.org/t/differentialequations-jl-stuck-at-initial-value-when-using-function/57716)

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**Author:** [@DCT](https://discourse.julialang.org/u/DCT)\
**Replies:** 3\
**Last updated:** [March 22, 2021, 2:58pm UTC](https://discourse.julialang.org/t/differentialequations-jl-stuck-at-initial-value-when-using-function/57716 "2021-03-22T14:58:09Z")

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Hi all, Being new to Julia, I started playing around a bit with differential equations. I started with a simple system, du = A \* u where A is an n\*n array, and u a vector of length n. when I set up the system as f(u…

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## [Sysimage with workload in VSCode?](https://discourse.julialang.org/t/sysimage-with-workload-in-vscode/57717)

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**Author:** [@stefanjwojcik](https://discourse.julialang.org/u/stefanjwojcik)\
**Replies:** 3\
**Last updated:** [March 22, 2021, 2:32pm UTC](https://discourse.julialang.org/t/sysimage-with-workload-in-vscode/57717 "2021-03-22T14:32:01Z")

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Hi All, I’m trying to ship some Julia code to a non-Julia user colleague and I want them to be able to run it without installing many dependencies. I’d also love if some of the functions were precompiled so they would r…

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## [Can I install Plots without GR](https://discourse.julialang.org/t/can-i-install-plots-without-gr/57380)

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**Author:** [@melonedo](https://discourse.julialang.org/u/melonedo)\
**Replies:** 3\
**Last updated:** [March 22, 2021, 2:16pm UTC](https://discourse.julialang.org/t/can-i-install-plots-without-gr/57380 "2021-03-22T14:16:17Z")

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Currently, when I Pkg.add("Plots"), GR is also installed and built. And if GR is not correctly built, which usual due to network issue, using Plots may fail because GR will also be imported. I know I can add and switch t…

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## [How can I get useful diff messeges when comparing tuples?](https://discourse.julialang.org/t/how-can-i-get-useful-diff-messeges-when-comparing-tuples/57709)

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**Author:** [@justinsgray](https://discourse.julialang.org/u/justinsgray)\
**Replies:** 3\
**Last updated:** [March 22, 2021, 1:34pm UTC](https://discourse.julialang.org/t/how-can-i-get-useful-diff-messeges-when-comparing-tuples/57709 "2021-03-22T13:34:58Z")

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Im just spooling up with Julia, and Im having difficulty getting useful diff-msgs on some of the tests I am writing, when using ExtendedTestSet. The problem seems to be related to the type of vectors/tuples i am comparin…

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## [Read CSV, converting column containing String "Date" to a specific proper Date format](https://discourse.julialang.org/t/read-csv-converting-column-containing-string-date-to-a-specific-proper-date-format/57712)

<div class="topic-metadata">

**Author:** [@Nash](https://discourse.julialang.org/u/Nash)\
**Replies:** 1\
**Last updated:** [March 22, 2021, 1:54pm UTC](https://discourse.julialang.org/t/read-csv-converting-column-containing-string-date-to-a-specific-proper-date-format/57712 "2021-03-22T13:54:33Z")

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Consider data = CSV.read(“C:/Stocks/file.csv”) One column of data holds information about dates in the format shown by, for example, “Feb 1, 2021”. I wish to convert that entire column of data to the proper date-forma…

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## [Expectation of multidimensional value function with discrete states](https://discourse.julialang.org/t/expectation-of-multidimensional-value-function-with-discrete-states/57570)

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**Author:** [@dadada\_dadada](https://discourse.julialang.org/u/dadada_dadada)\
**Replies:** 18\
**Last updated:** [March 22, 2021, 1:43pm UTC](https://discourse.julialang.org/t/expectation-of-multidimensional-value-function-with-discrete-states/57570 "2021-03-22T13:43:44Z")

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Hello, I have a dynamic programming problem in which I need to calculate the conditional expectation of the next period value function of my problem. The expectation is conditional on my current states and action, and …

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## [Creating sysimage fails on the Vagrant machine (Ubuntu)](https://discourse.julialang.org/t/creating-sysimage-fails-on-the-vagrant-machine-ubuntu/57664)

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**Author:** [@curious](https://discourse.julialang.org/u/curious)\
**Replies:** 2\
**Last updated:** [March 22, 2021, 1:21pm UTC](https://discourse.julialang.org/t/creating-sysimage-fails-on-the-vagrant-machine-ubuntu/57664 "2021-03-22T13:21:09Z")

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Hi, Today is the first time I created a custom sysimage on my Mac, and it works like a charm. Given how much I like it, I tried also creating it on a Vagrant machine that is running Ubuntu. It keeps failing for some rea…

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## [ForwardDiff.jl and \`@printf\`](https://discourse.julialang.org/t/forwarddiff-jl-and-printf/57694)

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**Author:** [@ranocha](https://discourse.julialang.org/u/ranocha)\
**Replies:** 3\
**Last updated:** [March 22, 2021, 1:02pm UTC](https://discourse.julialang.org/t/forwarddiff-jl-and-printf/57694 "2021-03-22T13:02:26Z")

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What are best practices regarding automatic differentiation of functions that print some intermediate results using ForwardDiff.jl? For example, using Julia v1.6.0-rc3 and ForwardDiff.jl v0.10.17, I get julia\> using For…

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## [Promote\_shape dimension mismatch](https://discourse.julialang.org/t/promote-shape-dimension-mismatch/57529)

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**Author:** [@Marcell\_Havlik](https://discourse.julialang.org/u/Marcell_Havlik)\
**Replies:** 17\
**Last updated:** [March 20, 2021, 5:58pm UTC](https://discourse.julialang.org/t/promote-shape-dimension-mismatch/57529 "2021-03-20T17:58:11Z")

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Hey, I saw an error message: ERROR: LoadError: DimensionMismatch("dimensions must match: a has dims (Base.OneTo(2), Base.OneTo(3), Base.OneTo(2), Base.OneTo(6)), b has dims (Base.OneTo(2), Base.OneTo(3), Base.OneTo(2),…

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## [Problem: setting up parametric struct](https://discourse.julialang.org/t/problem-setting-up-parametric-struct/57699)

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**Author:** [@ZettEff](https://discourse.julialang.org/u/ZettEff)\
**Replies:** 3\
**Last updated:** [March 22, 2021, 11:55am UTC](https://discourse.julialang.org/t/problem-setting-up-parametric-struct/57699 "2021-03-22T11:55:42Z")

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I am struggling to correctly set up a parametric struct. This is most likely a very stupid question, however, I really don’t understand what is wrong with my code so please be gentle on me… I want to create a struct wh…

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## [\[ANN\] TensorAlgebra.jl: Taking covariance seriously](https://discourse.julialang.org/t/ann-tensoralgebra-jl-taking-covariance-seriously/43587)

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**Author:** [@anon67531922](https://discourse.julialang.org/u/anon67531922)\
**Replies:** 49\
**Last updated:** [March 22, 2021, 11:52am UTC](https://discourse.julialang.org/t/ann-tensoralgebra-jl-taking-covariance-seriously/43587 "2021-03-22T11:52:06Z")

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TL;DR Vector spaces are first class. Tensors are linear maps from a vector space to an underlying field t: V\\to K Dual spaces are first class with α = Covector(V,\[1,2,3\]) Vectors are degree-1 tensors whose domain is …

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## [Where are the TagBot logs?](https://discourse.julialang.org/t/where-are-the-tagbot-logs/57673)

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**Author:** [@simsurace](https://discourse.julialang.org/u/simsurace)\
**Replies:** 2\
**Last updated:** [March 22, 2021, 10:49am UTC](https://discourse.julialang.org/t/where-are-the-tagbot-logs/57673 "2021-03-22T10:49:16Z")

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I’m getting this message in my TagBot trigger issue: Triggering TagBot for merged registry pull request This extra notification is being sent because I expected a tag to exist by now, but it doesn’t. You may want to …

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## [Make function more julian / simpler](https://discourse.julialang.org/t/make-function-more-julian-simpler/57603)

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**Author:** [@ZettEff](https://discourse.julialang.org/u/ZettEff)\
**Replies:** 20\
**Last updated:** [March 22, 2021, 10:47am UTC](https://discourse.julialang.org/t/make-function-more-julian-simpler/57603 "2021-03-22T10:47:59Z")

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Can someone tell me how to simplify (or make more) my following function. It works. I am just curious if (and quite certain) there is a simpler way. I have two arrays and I want to remove from first array all instances…

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## [OrderedCollections vs DataStructures](https://discourse.julialang.org/t/orderedcollections-vs-datastructures/57658)

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**Author:** [@HugoTrentesaux](https://discourse.julialang.org/u/HugoTrentesaux)\
**Replies:** 2\
**Last updated:** [March 22, 2021, 9:53am UTC](https://discourse.julialang.org/t/orderedcollections-vs-datastructures/57658 "2021-03-22T09:53:47Z")

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In OrderedCollections page, it says it was split from DataStructures without giving more detail. Which one should I use in which case?

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## [\[ANN\] BayesianExperiments.jl: A Toolbox for Bayesian AB Testing Experiments](https://discourse.julialang.org/t/ann-bayesianexperiments-jl-a-toolbox-for-bayesian-ab-testing-experiments/57639)

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**Author:** [@jetafull](https://discourse.julialang.org/u/jetafull)\
**Replies:** 2\
**Last updated:** [March 22, 2021, 8:19am UTC](https://discourse.julialang.org/t/ann-bayesianexperiments-jl-a-toolbox-for-bayesian-ab-testing-experiments/57639 "2021-03-22T08:19:57Z")

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I am excited to announce a new package: BayesianExperiments.jl. This package provides a toolbox for running various types of Bayesian AB testing experiments, including Conjugate prior models, Bayes factor models. Current…

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## [Accelerating computations Neural Network](https://discourse.julialang.org/t/accelerating-computations-neural-network/57670)

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**Author:** [@moby75](https://discourse.julialang.org/u/moby75)\
**Replies:** 6\
**Last updated:** [March 22, 2021, 7:30am UTC](https://discourse.julialang.org/t/accelerating-computations-neural-network/57670 "2021-03-22T07:30:02Z")

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I am new to Julia and to Cuda programming. I am using Julia 1.0.5. I wrote a code to do neural network inferences: it consists on a series of multiplications (neural network weights\* Input/layers) and adding Biases. I …

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## [Why does using keys() on an array produce LinearIndices?](https://discourse.julialang.org/t/why-does-using-keys-on-an-array-produce-linearindices/57618)

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**Author:** [@anon60034542](https://discourse.julialang.org/u/anon60034542)\
**Replies:** 7\
**Last updated:** [March 22, 2021, 5:02am UTC](https://discourse.julialang.org/t/why-does-using-keys-on-an-array-produce-linearindices/57618 "2021-03-22T05:02:24Z")

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Suppose I had the following array and used keys() to extract the indices: trance\_singers = String\["Emma Hewitt","Carrie skipper","Justine Suissa"\] println(typeof(keys(singers))) # LinearIndices{1,Tuple{Base.OneTo{Int32}…

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## [How to attach to an existing remote REPL?](https://discourse.julialang.org/t/how-to-attach-to-an-existing-remote-repl/27608)

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**Author:** [@csavorgn](https://discourse.julialang.org/u/csavorgn)\
**Replies:** 23\
**Last updated:** [March 22, 2021, 5:01am UTC](https://discourse.julialang.org/t/how-to-attach-to-an-existing-remote-repl/27608 "2021-03-22T05:01:07Z")

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Hi, In my workflow I need to run several simulations which make use of the DifferentialEquations package. To automate running the simulations I need to start the simulations from command line (and not within the Julia …

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## [Julia not able to convert Array to a series data for plotting](https://discourse.julialang.org/t/julia-not-able-to-convert-array-to-a-series-data-for-plotting/57669)

<div class="topic-metadata">

**Author:** [@oo92](https://discourse.julialang.org/u/oo92)\
**Replies:** 22\
**Last updated:** [March 22, 2021, 2:30am UTC](https://discourse.julialang.org/t/julia-not-able-to-convert-array-to-a-series-data-for-plotting/57669 "2021-03-22T02:30:52Z")

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I am trying to plot a dataframe I created from an existing dataframe. Basically I just took about 5 rows and all N-4 columns and created a new dataframe. I wanted to plot this but Julia (on Pluto.jl) is throwing this err…

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## [\[ANN\] LASArrays.jl](https://discourse.julialang.org/t/ann-lasarrays-jl/57679)

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**Author:** [@Crghilardi](https://discourse.julialang.org/u/Crghilardi)\
**Replies:** 0\
**Last updated:** [March 22, 2021, 1:36am UTC](https://discourse.julialang.org/t/ann-lasarrays-jl/57679 "2021-03-22T01:36:22Z")

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I just finished pushing the first commit for LASArrays.jl. It’s still a bit rough, but I thought it might interest others here. This is a package for working with .las LiDAR files and I made this package because I wante…

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## [Boundary Value Problem with ModellingToolkit or DiffEqOperators](https://discourse.julialang.org/t/boundary-value-problem-with-modellingtoolkit-or-diffeqoperators/57656)

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**Author:** [@kkakosim](https://discourse.julialang.org/u/kkakosim)\
**Replies:** 3\
**Last updated:** [March 21, 2021, 8:45pm UTC](https://discourse.julialang.org/t/boundary-value-problem-with-modellingtoolkit-or-diffeqoperators/57656 "2021-03-21T20:45:00Z")

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At first I thought that there was a bug in the packages but probably I am doing something (completely wrong). I am trying to run the bellow spherical coordinates system with Boundary Values. But not sure if it even makes…

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