# Latest

**URL:** https://discourse.julialang.org/latest.md?page=305

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

**Page:** 306

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## [Initialize a SDP solver with Convex](https://discourse.julialang.org/t/initialize-a-sdp-solver-with-convex/115339)

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**Author:** [@gustave\_Robichon](https://discourse.julialang.org/u/gustave_Robichon)\
**Replies:** 6\
**Last updated:** [October 7, 2024, 2:38pm UTC](https://discourse.julialang.org/t/initialize-a-sdp-solver-with-convex/115339 "2024-10-07T14:38:35Z")

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hello there :slight\_smile: I am using julia to solve some Semi-definite Problem. I use Convex to define the problem and the constraints, then I use Hypatia to solve it : M = HermitianSemidefinite(N) problem = minimize…

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## [Examodels: using constraint as empty object for constraint!](https://discourse.julialang.org/t/examodels-using-constraint-as-empty-object-for-constraint/120911)

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**Author:** [@KSepetanc](https://discourse.julialang.org/u/KSepetanc)\
**Replies:** 4\
**Last updated:** [October 7, 2024, 2:09pm UTC](https://discourse.julialang.org/t/examodels-using-constraint-as-empty-object-for-constraint/120911 "2024-10-07T14:09:38Z")

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I am trying to implement control neutrality constraint. That is, a constraint that requires that if some generator increased power that others decrease (sum is zero). In this demo test case there are only two variables …

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## [Best practices for NonlinearSolve definition with temporary arrays](https://discourse.julialang.org/t/best-practices-for-nonlinearsolve-definition-with-temporary-arrays/115763)

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**Author:** [@dieg0](https://discourse.julialang.org/u/dieg0)\
**Replies:** 6\
**Last updated:** [October 7, 2024, 1:01pm UTC](https://discourse.julialang.org/t/best-practices-for-nonlinearsolve-definition-with-temporary-arrays/115763 "2024-10-07T13:01:48Z")

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Hi all, I am relatively new to Julia. Apologies as it’s a long one but I couldn’t find a solution. I am using NonlinearSolve.jl to solve a somewhat “complicated” system of equations g(u, p) = 0. The reason the function …

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## [Timing compilation when using threads](https://discourse.julialang.org/t/timing-compilation-when-using-threads/121001)

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**Author:** [@theogf](https://discourse.julialang.org/u/theogf)\
**Replies:** 0\
**Last updated:** [October 7, 2024, 11:56am UTC](https://discourse.julialang.org/t/timing-compilation-when-using-threads/121001 "2024-10-07T11:56:38Z")

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Is it possible to correctly measure compilation time when using Tasks on separate threads? I have tried using the 1.11 @timed but get inconsistent timings for the compilation time. I also don’t have a clear picture of …

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## [Is Julia 2.0 needed?](https://discourse.julialang.org/t/is-julia-2-0-needed/120842)

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**Author:** [@Kirby\_Zhang](https://discourse.julialang.org/u/Kirby_Zhang)\
**Replies:** 57\
**Last updated:** [October 7, 2024, 11:17am UTC](https://discourse.julialang.org/t/is-julia-2-0-needed/120842 "2024-10-07T11:17:56Z")

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Python made a big break by going from Python2 to Python3. I haven’t seen much talk about Julia 2.0; the last threads that kind of referenced were from already from 2018. If 2.0 ever comes, I would like Julia to have sev…

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## [How to increase number of facets for cylinder plotting in Makie](https://discourse.julialang.org/t/how-to-increase-number-of-facets-for-cylinder-plotting-in-makie/120984)

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**Author:** [@brianguenter](https://discourse.julialang.org/u/brianguenter)\
**Replies:** 1\
**Last updated:** [October 7, 2024, 1:55am UTC](https://discourse.julialang.org/t/how-to-increase-number-of-facets-for-cylinder-plotting-in-makie/120984 "2024-10-07T01:55:42Z")

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I am plotting a cylinder in makie like so: julia\> cyl = GeometryBasics.Cylinder(GeometryBasics.Point(0.0,0.0,0.0),GeometryBasics.Point(0.0,1.0,0.0),.5) Cylinder3{Float64}(\[0.0, 0.0, 0.0\], \[0.0, 1.0, 0.0\], 0.5) julia\> m…

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## [Julia v0.6 to v1.10 appreciation post](https://discourse.julialang.org/t/julia-v0-6-to-v1-10-appreciation-post/120823)

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**Author:** [@Samuel\_Palato](https://discourse.julialang.org/u/Samuel_Palato)\
**Replies:** 3\
**Last updated:** [October 7, 2024, 8:29am UTC](https://discourse.julialang.org/t/julia-v0-6-to-v1-10-appreciation-post/120823 "2024-10-07T08:29:16Z")

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Hi! I had used julia v0.6 to write some physical modeling code. The code wasn’t used for quite some years (my PhD was over). We recently decided to dust it off and upgrade it to work with julia v1.10, so it would be eas…

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## [Elements in my \`Set\` are not unique](https://discourse.julialang.org/t/elements-in-my-set-are-not-unique/120985)

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**Author:** [@sadish-d](https://discourse.julialang.org/u/sadish-d)\
**Replies:** 2\
**Last updated:** [October 7, 2024, 3:14am UTC](https://discourse.julialang.org/t/elements-in-my-set-are-not-unique/120985 "2024-10-07T03:14:36Z")

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The documentation for Set says: Elements in a Set are unique, as determined by the elements’ definition of isequal. This doesn’t seem to be true: struct S x::Vector{Int} S() = new(Int\[\]) end Base.isequal(::S…

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## [Warning displayed after running](https://discourse.julialang.org/t/warning-displayed-after-running/120947)

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**Author:** [@Jimery](https://discourse.julialang.org/u/Jimery)\
**Replies:** 2\
**Last updated:** [October 7, 2024, 2:00am UTC](https://discourse.julialang.org/t/warning-displayed-after-running/120947 "2024-10-07T02:00:25Z")

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┌ Warning: The model has been modified since the last call to optimize! (or optimize! has not been called yet). If you are iteratively querying solution information and modifying a model, query all the results first, the…

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## [Why are Mixed integer programming solvers focused on finding cuts and not so much on search?](https://discourse.julialang.org/t/why-are-mixed-integer-programming-solvers-focused-on-finding-cuts-and-not-so-much-on-search/120945)

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**Author:** [@Tarny\_GG\_Channie](https://discourse.julialang.org/u/Tarny_GG_Channie)\
**Replies:** 4\
**Last updated:** [October 7, 2024, 1:58am UTC](https://discourse.julialang.org/t/why-are-mixed-integer-programming-solvers-focused-on-finding-cuts-and-not-so-much-on-search/120945 "2024-10-07T01:58:04Z")

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Hi. I’ve written many mixed-integer programming problems and sent them to solvers (HiGHS and Gurobi). The solvers seem to follow this pattern. Adding cuts at the root node (Gomory cut among other cuts) Doing a branch a…

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## [When to define a \`module\`](https://discourse.julialang.org/t/when-to-define-a-module/120935)

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**Author:** [@Santiago\_Lopez](https://discourse.julialang.org/u/Santiago_Lopez)\
**Replies:** 22\
**Last updated:** [October 6, 2024, 11:20pm UTC](https://discourse.julialang.org/t/when-to-define-a-module/120935 "2024-10-06T23:20:53Z")

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When developing a package (call it MyPackage) one usually has a “main” function src/MyPackage.jl. This file is a module with a bunch of using, export and include statements. The export statements establish the API of th…

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## [2nd order optimization for Julia](https://discourse.julialang.org/t/2nd-order-optimization-for-julia/120966)

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**Author:** [@Tarny\_GG\_Channie](https://discourse.julialang.org/u/Tarny_GG_Channie)\
**Replies:** 1\
**Last updated:** [October 6, 2024, 10:34pm UTC](https://discourse.julialang.org/t/2nd-order-optimization-for-julia/120966 "2024-10-06T22:34:17Z")

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Lately, I’ve seen second-order optimization suddenly becoming a trend in deep learning. Is this An opportunity that Julia neural network system can do well? Something that would rather shift the balance toward PyTorch…

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## [Pseudoinverse x Factorization in a repeated linear solve: when to use which?](https://discourse.julialang.org/t/pseudoinverse-x-factorization-in-a-repeated-linear-solve-when-to-use-which/120972)

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**Author:** [@marcsgil](https://discourse.julialang.org/u/marcsgil)\
**Replies:** 6\
**Last updated:** [October 6, 2024, 9:41pm UTC](https://discourse.julialang.org/t/pseudoinverse-x-factorization-in-a-repeated-linear-solve-when-to-use-which/120972 "2024-10-06T21:41:34Z")

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Assume I want to solve Ax = b for a bunch of different b's, but keeping A fixed. Furthermore, assume A is a tall matrix. The question is, what are the pros and cons of precomputing the pseudoinverse of A and precomputing…

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## [IO Parallelism Strategies](https://discourse.julialang.org/t/io-parallelism-strategies/120970)

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**Author:** [@mrufsvold](https://discourse.julialang.org/u/mrufsvold)\
**Replies:** 3\
**Last updated:** [October 6, 2024, 9:14pm UTC](https://discourse.julialang.org/t/io-parallelism-strategies/120970 "2024-10-06T21:14:46Z")

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I have a use case with many small IOs (get/put S3 objects \<300mb), a heartbeat (keep SQS message from timing out), and a heavy compute task which consumes a constant stream of inputs. The machine I’m using has 2 cores. R…

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## [Julia interactive learning](https://discourse.julialang.org/t/julia-interactive-learning/120955)

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**Author:** [@hack3rcon](https://discourse.julialang.org/u/hack3rcon)\
**Replies:** 2\
**Last updated:** [October 6, 2024, 6:22pm UTC](https://discourse.julialang.org/t/julia-interactive-learning/120955 "2024-10-06T18:22:20Z")

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Hello, Is there a site like https://try.ruby-lang.org/ to learn Julia? Thank you.

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## [Numba/pixie](https://discourse.julialang.org/t/numba-pixie/120981)

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**Author:** [@berceanu](https://discourse.julialang.org/u/berceanu)\
**Replies:** 0\
**Last updated:** [October 6, 2024, 4:51pm UTC](https://discourse.julialang.org/t/numba-pixie/120981 "2024-10-06T16:51:58Z")

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What do you think about this approach to combining AOT/JIT: pixie There’s a talk about it here.

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## [Solving a Diagonal ODE using DifferentialEquations.jl](https://discourse.julialang.org/t/solving-a-diagonal-ode-using-differentialequations-jl/120956)

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**Author:** [@albertomercurio](https://discourse.julialang.org/u/albertomercurio)\
**Replies:** 8\
**Last updated:** [October 6, 2024, 11:43am UTC](https://discourse.julialang.org/t/solving-a-diagonal-ode-using-differentialequations-jl/120956 "2024-10-06T11:43:21Z")

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Hello, I have the following ODE system \\dot{\\mathbf{u}} = \\mathbf{A} \\ \\mathbf{u} where \\mathbf{u} is a vector and \\mathbf{A} is a Diagonal matrix. The following ODE system admits an analytical solution of the form …

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## [How to copy view of CuArray to Array efficiently?](https://discourse.julialang.org/t/how-to-copy-view-of-cuarray-to-array-efficiently/120960)

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**Author:** [@0samuraiE](https://discourse.julialang.org/u/0samuraiE)\
**Replies:** 4\
**Last updated:** [October 6, 2024, 11:08am UTC](https://discourse.julialang.org/t/how-to-copy-view-of-cuarray-to-array-efficiently/120960 "2024-10-06T11:08:53Z")

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Hi all. For some reason, I encountered a GPU allocation problem when I copied a CuArray view. I tried several copying methods, but the third result was much slower. Should I avoid copying the CuArray view to the host? …

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## [Best way to manage TODO in your code](https://discourse.julialang.org/t/best-way-to-manage-todo-in-your-code/120967)

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**Author:** [@xiaodai](https://discourse.julialang.org/u/xiaodai)\
**Replies:** 3\
**Last updated:** [October 6, 2024, 9:07am UTC](https://discourse.julialang.org/t/best-way-to-manage-todo-in-your-code/120967 "2024-10-06T09:07:42Z")

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How does everyone manage their TODOs in the code? Of course I can do a TODO search in VSCode and have all the TODO surfaced. In R there’s a package called todor which does the same thing. There are quite a lot package…

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## [Determine if Array is Mmap?](https://discourse.julialang.org/t/determine-if-array-is-mmap/87354)

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**Author:** [@JesperMartinsson](https://discourse.julialang.org/u/JesperMartinsson)\
**Replies:** 4\
**Last updated:** [October 6, 2024, 7:34am UTC](https://discourse.julialang.org/t/determine-if-array-is-mmap/87354 "2024-10-06T07:34:23Z")

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Is there a way to determine if an Array is memory mapped or standard? For example, taken from the doc: # Create a file for mmapping # (you could alternatively use mmap to do this step, too) using Mmap A = rand(1:20, 5,…

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## [Reducing usage of resources during precompilation](https://discourse.julialang.org/t/reducing-usage-of-resources-during-precompilation/109903)

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**Author:** [@pvarshinee](https://discourse.julialang.org/u/pvarshinee)\
**Replies:** 9\
**Last updated:** [October 6, 2024, 2:14am UTC](https://discourse.julialang.org/t/reducing-usage-of-resources-during-precompilation/109903 "2024-10-06T02:14:00Z")

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Hello, I am trying to set up a Julia kernel in mybinder.org with a few packages. Here is the GitHub repo for the kernel. I find the precompilation failing due to the process overrunning the maximum amount of RAM (2GB) pr…

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## [How to change the artifact path temporarily?](https://discourse.julialang.org/t/how-to-change-the-artifact-path-temporarily/120950)

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**Author:** [@happyxie](https://discourse.julialang.org/u/happyxie)\
**Replies:** 3\
**Last updated:** [October 5, 2024, 7:28pm UTC](https://discourse.julialang.org/t/how-to-change-the-artifact-path-temporarily/120950 "2024-10-05T19:28:47Z")

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I am trying to download some matrices from SuiteSparseMatrixCollection and it always downloads it to C:\\Users\\username\\.julia\\artifacts . Is it possible to download it to the current project directory by temporarily chan…

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## [How to use GPU acceleration to solve linear equation Ax=b](https://discourse.julialang.org/t/how-to-use-gpu-acceleration-to-solve-linear-equation-ax-b/120841)

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**Author:** [@automaticvehiclerook](https://discourse.julialang.org/u/automaticvehiclerook)\
**Replies:** 9\
**Last updated:** [October 5, 2024, 5:35am UTC](https://discourse.julialang.org/t/how-to-use-gpu-acceleration-to-solve-linear-equation-ax-b/120841 "2024-10-05T05:35:07Z")

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In my experiment,I want to solve the equation Ax=b on GPU to accelerate the process.I have tried the iterative solver from Kryvol.jl and cuSOLVER,but the GPU is still slower than CPU.Is that normal? using CUDA using Spa…

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## [When I am running Julia in VS Code and I press Shift Enter the line of Code is not evaluated. Help](https://discourse.julialang.org/t/when-i-am-running-julia-in-vs-code-and-i-press-shift-enter-the-line-of-code-is-not-evaluated-help/120943)

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**Author:** [@larrysievers](https://discourse.julialang.org/u/larrysievers)\
**Replies:** 2\
**Last updated:** [October 5, 2024, 11:48am UTC](https://discourse.julialang.org/t/when-i-am-running-julia-in-vs-code-and-i-press-shift-enter-the-line-of-code-is-not-evaluated-help/120943 "2024-10-05T11:48:24Z")

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How do I get VS Code, running with Julia, to evaluate a line of Code? I thought pressing Shift Enter was the way to accomplish evaluating a line of Code.

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## [How to start using LLMs to help write Julia code?](https://discourse.julialang.org/t/how-to-start-using-llms-to-help-write-julia-code/120912)

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**Author:** [@Nathan\_Boyer](https://discourse.julialang.org/u/Nathan_Boyer)\
**Replies:** 6\
**Last updated:** [October 5, 2024, 11:11am UTC](https://discourse.julialang.org/t/how-to-start-using-llms-to-help-write-julia-code/120912 "2024-10-05T11:11:58Z")

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Continuing the discussion from Is Julia 2.0 needed?: I’m curious how people are integrating AI tools to help them code. Seems this is growing in popularity, but I’ve not really looked into how to do it myself yet. Are …

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## [Help needed to learn Julia](https://discourse.julialang.org/t/help-needed-to-learn-julia/113783)

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**Author:** [@Hassan1](https://discourse.julialang.org/u/Hassan1)\
**Replies:** 3\
**Last updated:** [October 5, 2024, 10:49am UTC](https://discourse.julialang.org/t/help-needed-to-learn-julia/113783 "2024-10-05T10:49:06Z")

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Hi all I am going to start my graduate studies in energy Optimization in fall 24. With some time in hand I want to learn basics of Julia. I know about power flow and know coding in Python. Can someone suggest some refe…

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## [Julia manual evaluates the expression. Why does it report an error when I run it myself?](https://discourse.julialang.org/t/julia-manual-evaluates-the-expression-why-does-it-report-an-error-when-i-run-it-myself/120954)

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**Author:** [@qianlvzhe](https://discourse.julialang.org/u/qianlvzhe)\
**Replies:** 3\
**Last updated:** [October 5, 2024, 10:30am UTC](https://discourse.julialang.org/t/julia-manual-evaluates-the-expression-why-does-it-report-an-error-when-i-run-it-myself/120954 "2024-10-05T10:30:02Z")

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## [Best way to ensure only certain values are allowed for a particular arg?](https://discourse.julialang.org/t/best-way-to-ensure-only-certain-values-are-allowed-for-a-particular-arg/120952)

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**Author:** [@xiaodai](https://discourse.julialang.org/u/xiaodai)\
**Replies:** 4\
**Last updated:** [October 5, 2024, 10:17am UTC](https://discourse.julialang.org/t/best-way-to-ensure-only-certain-values-are-allowed-for-a-particular-arg/120952 "2024-10-05T10:17:53Z")

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In trying to write a clone of numpy API in Julia, I see the numpy.array has an argument which accepts only 4 values but is other a string in Python. The 4 possibles values are C , F, A, K. So I want to make sure that ar…

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## [Is anyone aware of efforts to reimplement R base functions or numpy in Julia for learning?](https://discourse.julialang.org/t/is-anyone-aware-of-efforts-to-reimplement-r-base-functions-or-numpy-in-julia-for-learning/120920)

<div class="topic-metadata">

**Author:** [@xiaodai](https://discourse.julialang.org/u/xiaodai)\
**Replies:** 5\
**Last updated:** [October 5, 2024, 7:15am UTC](https://discourse.julialang.org/t/is-anyone-aware-of-efforts-to-reimplement-r-base-functions-or-numpy-in-julia-for-learning/120920 "2024-10-05T07:15:20Z")

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I think I saw a table mapping R functions to Julia once. But I was thinking if it’s possible to implement base r functions in Julia to replicate the arg names etc and replicate the functionality. Both as a learning opp f…

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## [How to define a Julia Vector with only integers ≥ 0](https://discourse.julialang.org/t/how-to-define-a-julia-vector-with-only-integers-0/120894)

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**Author:** [@Brinkhuis](https://discourse.julialang.org/u/Brinkhuis)\
**Replies:** 3\
**Last updated:** [October 5, 2024, 4:18am UTC](https://discourse.julialang.org/t/how-to-define-a-julia-vector-with-only-integers-0/120894 "2024-10-05T04:18:30Z")

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As input for a function, I need a Vector with values greater than or equal to zero. I tried l = Array{\>:UInt8, 1} However push!(l, 9) throws an error. MethodError: no method matching push!(::Type{Vector{\>:UInt8}}, ::I…

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