# Latest

**URL:** https://discourse.julialang.org/latest.md?page=269

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

**Page:** 270

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## [Why JLD2.jl is 40x slower than Arrow.jl](https://discourse.julialang.org/t/why-jld2-jl-is-40x-slower-than-arrow-jl/122217)

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**Author:** [@Sixzero](https://discourse.julialang.org/u/Sixzero)\
**Replies:** 24\
**Last updated:** [November 25, 2024, 9:59am UTC](https://discourse.julialang.org/t/why-jld2-jl-is-40x-slower-than-arrow-jl/122217 "2024-11-25T09:59:38Z")

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I have this gist: JLD2 is actually simply for reading in a 30 MB file with keys =\> randn(500) is 40x slower than Arrow.jl. How? I mean how come JLD2 generality sacrificed 40x speed difference?

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## [Variable definition like C++](https://discourse.julialang.org/t/variable-definition-like-c/123038)

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**Author:** [@hack3rcon](https://discourse.julialang.org/u/hack3rcon)\
**Replies:** 7\
**Last updated:** [November 25, 2024, 8:53am UTC](https://discourse.julialang.org/t/variable-definition-like-c/123038 "2024-11-25T08:53:28Z")

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Hello, In the C++ programming language, the definition of a variable is as follows: int res = 1; How is this done in Julia? Thank you.

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## [How to determine whether the rule of an DynamicalSystem instance is inplace?](https://discourse.julialang.org/t/how-to-determine-whether-the-rule-of-an-dynamicalsystem-instance-is-inplace/123041)

<div class="topic-metadata">

**Author:** [@andreasmorr](https://discourse.julialang.org/u/andreasmorr)\
**Replies:** 2\
**Last updated:** [November 25, 2024, 8:59am UTC](https://discourse.julialang.org/t/how-to-determine-whether-the-rule-of-an-dynamicalsystem-instance-is-inplace/123041 "2024-11-25T08:59:01Z")

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I would like to define a function that takes a DynamicalSystem ds as an argument and computes the Jacobian of dynamic\_rule(ds) for further analysis. For this, it would be good to know whether dynamic\_rule(ds) returns an …

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## [Factorial program](https://discourse.julialang.org/t/factorial-program/123010)

<div class="topic-metadata">

**Author:** [@hack3rcon](https://discourse.julialang.org/u/hack3rcon)\
**Replies:** 4\
**Last updated:** [November 25, 2024, 6:55am UTC](https://discourse.julialang.org/t/factorial-program/123010 "2024-11-25T06:55:22Z")

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Hello, I know that Julia has a function called factorial. I have written a program as follows to do this: function fact(a) F = 1 for n = 1 : (a - 1) F = F \* (n + 1) println(F) end end Is it…

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## [Interpolation for missing data:](https://discourse.julialang.org/t/interpolation-for-missing-data/122829)

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**Author:** [@GeodeticR](https://discourse.julialang.org/u/GeodeticR)\
**Replies:** 10\
**Last updated:** [November 25, 2024, 4:02am UTC](https://discourse.julialang.org/t/interpolation-for-missing-data/122829 "2024-11-25T04:02:41Z")

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Hi everyone: some background: I have a questions about data interpolation. I have some GPS station data which is missing data. This can occur for various reason (Software updates, hardware swaps, etc…). However, these …

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## [Neovim lsp unused variables bug](https://discourse.julialang.org/t/neovim-lsp-unused-variables-bug/117363)

<div class="topic-metadata">

**Author:** [@pp4bb](https://discourse.julialang.org/u/pp4bb)\
**Replies:** 1\
**Last updated:** [November 25, 2024, 12:21am UTC](https://discourse.julialang.org/t/neovim-lsp-unused-variables-bug/117363 "2024-11-25T00:21:39Z")

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Hi everyone, I’m using Neovim and the lsp linter presents a bug that tags all my variables as unused if passed as arguments or in different blocks. If anyone knows how to fix it I would be grateful (or instructions in ho…

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## [Various BSODs when precompiling many packages in WSL on ARM64](https://discourse.julialang.org/t/various-bsods-when-precompiling-many-packages-in-wsl-on-arm64/119611)

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**Author:** [@BioTurboNick](https://discourse.julialang.org/u/BioTurboNick)\
**Replies:** 15\
**Last updated:** [November 24, 2024, 11:36pm UTC](https://discourse.julialang.org/t/various-bsods-when-precompiling-many-packages-in-wsl-on-arm64/119611 "2024-11-24T23:36:38Z")

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I figured I should just post this in case others encounter this, because it seems like something that may be quite complicated to actually pin down. I have a Windows on ARM system (Surface Pro 11), and so need to run Ju…

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## [Visualizing Electric Equipotentials](https://discourse.julialang.org/t/visualizing-electric-equipotentials/123023)

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**Author:** [@NonDairyNeutrino](https://discourse.julialang.org/u/NonDairyNeutrino)\
**Replies:** 0\
**Last updated:** [November 24, 2024, 7:29pm UTC](https://discourse.julialang.org/t/visualizing-electric-equipotentials/123023 "2024-11-24T19:29:21Z")

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Hey all, not a question this time, but rather I just wanted to share something I whipped up a little bit ago for my class on introductory electromagnetism. Basically, it’s a drop-in way to visualize the contour lines of…

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## [DataFrames and MLJ](https://discourse.julialang.org/t/dataframes-and-mlj/122847)

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**Author:** [@Jose\_Ghislain\_Quenum](https://discourse.julialang.org/u/Jose_Ghislain_Quenum)\
**Replies:** 4\
**Last updated:** [November 24, 2024, 7:04pm UTC](https://discourse.julialang.org/t/dataframes-and-mlj/122847 "2024-11-24T19:04:31Z")

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Hi all, I am experiencing a weird behavior from Pluto. I have a dataset that contains more than 1M observations, although the size is about 75M. I’ve been able to cleanup the dataset and address the missing values. Howe…

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## [Using a runtime-length \`SVector\` within a closure allocates memory](https://discourse.julialang.org/t/using-a-runtime-length-svector-within-a-closure-allocates-memory/123020)

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**Author:** [@ferrolho](https://discourse.julialang.org/u/ferrolho)\
**Replies:** 6\
**Last updated:** [November 24, 2024, 5:40pm UTC](https://discourse.julialang.org/t/using-a-runtime-length-svector-within-a-closure-allocates-memory/123020 "2024-11-24T17:40:15Z")

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Consider the Test struct below. julia\> using StaticArrays julia\> struct Test{T,V} x::Int v::V Test(x::Int, v::V) where {T\<:Real,V\<:AbstractVector{T}} = new{T,V}(x, v) end Let’s …

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## [\`using\` and \`import\` can load files from the CWD? Surprising because it's not documented?](https://discourse.julialang.org/t/using-and-import-can-load-files-from-the-cwd-surprising-because-its-not-documented/122851)

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**Author:** [@world-peace](https://discourse.julialang.org/u/world-peace)\
**Replies:** 10\
**Last updated:** [November 24, 2024, 5:43pm UTC](https://discourse.julialang.org/t/using-and-import-can-load-files-from-the-cwd-surprising-because-its-not-documented/122851 "2024-11-24T17:43:46Z")

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A colleague of mine has just noticed some behavior relating to using and import which we found surprising. include will load a file from disk and (effectively) insert the code at the point where the include line ran. W…

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## [Is there a way to force language server to re-index a package?](https://discourse.julialang.org/t/is-there-a-way-to-force-language-server-to-re-index-a-package/122947)

<div class="topic-metadata">

**Author:** [@ufechner7](https://discourse.julialang.org/u/ufechner7)\
**Replies:** 6\
**Last updated:** [November 24, 2024, 3:55pm UTC](https://discourse.julialang.org/t/is-there-a-way-to-force-language-server-to-re-index-a-package/122947 "2024-11-24T15:55:05Z")

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If I am working on a package and add new functions the language server does not index them, which means hovering over the name of this function in examples or tests shows nothing and goto definition does not work. The f…

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## [Updating Label value twice in the same Makie event handler](https://discourse.julialang.org/t/updating-label-value-twice-in-the-same-makie-event-handler/122918)

<div class="topic-metadata">

**Author:** [@bjarthur](https://discourse.julialang.org/u/bjarthur)\
**Replies:** 3\
**Last updated:** [November 24, 2024, 3:04pm UTC](https://discourse.julialang.org/t/updating-label-value-twice-in-the-same-makie-event-handler/122918 "2024-11-24T15:04:13Z")

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in the MWE below, “start” is never displayed. is there a way to make it so? using GLMakie f = Figure() b = Button(f\[1,1\], label="foo") l = Label(f\[1,2\], "") on(b.clicks) do \_ l.text\[\] = "start" sleep(1) # lon…

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## [Macro for merging namedtuples and add suffixes in a type stable way](https://discourse.julialang.org/t/macro-for-merging-namedtuples-and-add-suffixes-in-a-type-stable-way/122975)

<div class="topic-metadata">

**Author:** [@ssdfg](https://discourse.julialang.org/u/ssdfg)\
**Replies:** 3\
**Last updated:** [November 24, 2024, 2:35pm UTC](https://discourse.julialang.org/t/macro-for-merging-namedtuples-and-add-suffixes-in-a-type-stable-way/122975 "2024-11-24T14:35:52Z")

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I’m trying to create a macro that will merge named tuples and change the key names by adding suffixes, in a way that’s type stable. Suppose that it’s guaranteed that nt1 and nt2 are the same type of named tuples, i.e. t…

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## [Chaining errors](https://discourse.julialang.org/t/chaining-errors/122984)

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**Author:** [@martin\_sanchez](https://discourse.julialang.org/u/martin_sanchez)\
**Replies:** 2\
**Last updated:** [November 24, 2024, 11:45am UTC](https://discourse.julialang.org/t/chaining-errors/122984 "2024-11-24T11:45:49Z")

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When a dictionary cannot retrieve values it shows two error types, is it making a kind of chaining or is it just inside the error message? LoadError: KeyError: key "d" not found

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## [Compat requirements for stdlibs](https://discourse.julialang.org/t/compat-requirements-for-stdlibs/123014)

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**Author:** [@e3c6](https://discourse.julialang.org/u/e3c6)\
**Replies:** 0\
**Last updated:** [November 24, 2024, 11:54am UTC](https://discourse.julialang.org/t/compat-requirements-for-stdlibs/123014 "2024-11-24T11:54:03Z")

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Since PSA: Compat requirements in the General registry are changing is locked, I’ll open a new thread here. I have a few questions: Is that linked post still the most up to date information on how to add compat bounds…

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## [New interpolation method ModelingToolkit](https://discourse.julialang.org/t/new-interpolation-method-modelingtoolkit/123000)

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**Author:** [@langestefan](https://discourse.julialang.org/u/langestefan)\
**Replies:** 4\
**Last updated:** [November 24, 2024, 11:30am UTC](https://discourse.julialang.org/t/new-interpolation-method-modelingtoolkit/123000 "2024-11-24T11:30:27Z")

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I am trying to use the new interpolation method via parameters (Callable parameters and interpolating data · ModelingToolkit.jl) However I am struggling to understand how I should use it. This is my model: @mtkmodel Si…

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## [AD Troubles in Flux and Unusual Loss](https://discourse.julialang.org/t/ad-troubles-in-flux-and-unusual-loss/122995)

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**Author:** [@gideonsimpson](https://discourse.julialang.org/u/gideonsimpson)\
**Replies:** 1\
**Last updated:** [November 24, 2024, 12:09am UTC](https://discourse.julialang.org/t/ad-troubles-in-flux-and-unusual-loss/122995 "2024-11-24T00:09:08Z")

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I’m struggling with the following issue. I want to train on a somewhat nonstandard loss function involving the gradient of the target. If everything worked, I would. use the following code: using Flux using Random usi…

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## [Capturing "sub" dependencies during precompilation](https://discourse.julialang.org/t/capturing-sub-dependencies-during-precompilation/123013)

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**Author:** [@sstroemer](https://discourse.julialang.org/u/sstroemer)\
**Replies:** 0\
**Last updated:** [November 24, 2024, 10:46am UTC](https://discourse.julialang.org/t/capturing-sub-dependencies-during-precompilation/123013 "2024-11-24T10:46:50Z")

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I have a package X which depends on Y which depends on Z. Z is not a direct dependency of X, and Y is done by a “third-party”, so I can’t influence it. I’m using some example code @compile\_workload, but still see a lot …

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## [Accessing axis in Makie plot recipes](https://discourse.julialang.org/t/accessing-axis-in-makie-plot-recipes/66006)

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**Author:** [@jlchan](https://discourse.julialang.org/u/jlchan)\
**Replies:** 5\
**Last updated:** [November 24, 2024, 9:18am UTC](https://discourse.julialang.org/t/accessing-axis-in-makie-plot-recipes/66006 "2024-11-24T09:18:18Z")

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Is there a way to access the axis in a Makie plot recipe? I’d like to apply xlims!(ax, ...) and set ax.aspect = .....

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## [KrylovKit svdsolve not working](https://discourse.julialang.org/t/krylovkit-svdsolve-not-working/122993)

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**Author:** [@EZ\_Money](https://discourse.julialang.org/u/EZ_Money)\
**Replies:** 3\
**Last updated:** [November 24, 2024, 7:07am UTC](https://discourse.julialang.org/t/krylovkit-svdsolve-not-working/122993 "2024-11-24T07:07:14Z")

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Hi! I’m having a little trouble understanding why svdsolve isn’t working- I can’t seem to find my error. I’m running using SparseArrays using LinearAlgebra import LinearMaps import KrylovKit A = \[1 0; 0 1\] Lambda,Phi,…

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## [Adding a filter to open\_dialogue() in Gtk4](https://discourse.julialang.org/t/adding-a-filter-to-open-dialogue-in-gtk4/122994)

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**Author:** [@elwwan](https://discourse.julialang.org/u/elwwan)\
**Replies:** 1\
**Last updated:** [November 24, 2024, 1:24am UTC](https://discourse.julialang.org/t/adding-a-filter-to-open-dialogue-in-gtk4/122994 "2024-11-24T01:24:43Z")

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Hello, I’m trying to add a filter to a file selection. Here is my current code : function on\_choose\_file\_button\_click(w) open\_dialog("Choose Data File"; start\_folder = pwd()) do filename global data\_file\_path = f…

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## [Using prettytables with Pluto](https://discourse.julialang.org/t/using-prettytables-with-pluto/69895)

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**Author:** [@Christopher\_Fisher](https://discourse.julialang.org/u/Christopher_Fisher)\
**Replies:** 24\
**Last updated:** [November 23, 2024, 9:59pm UTC](https://discourse.julialang.org/t/using-prettytables-with-pluto/69895 "2024-11-23T21:59:13Z")

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Hi all, PrettyTables for my custom type does not print out correctly in Pluto. It does work properly in the REPL however. I noticed that DataFrames uses PrettyTables and it works in Pluto. What is needed to get it to wo…

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## [How to solve the problem that the default installation path of the package is on the C drive??](https://discourse.julialang.org/t/how-to-solve-the-problem-that-the-default-installation-path-of-the-package-is-on-the-c-drive/122862)

<div class="topic-metadata">

**Author:** [@tiger\_Zhang](https://discourse.julialang.org/u/tiger_Zhang)\
**Replies:** 5\
**Last updated:** [November 23, 2024, 9:13pm UTC](https://discourse.julialang.org/t/how-to-solve-the-problem-that-the-default-installation-path-of-the-package-is-on-the-c-drive/122862 "2024-11-23T21:13:52Z")

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How to solve the problem that the default installation path of the package is on the C drive? What are the issues with changing an environment variable to change the default installation path? I added two new system env…

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## [Pluto.jl 0.20.3 broken image plots](https://discourse.julialang.org/t/pluto-jl-0-20-3-broken-image-plots/123002)

<div class="topic-metadata">

**Author:** [@jcbritobr](https://discourse.julialang.org/u/jcbritobr)\
**Replies:** 1\
**Last updated:** [November 23, 2024, 8:43pm UTC](https://discourse.julialang.org/t/pluto-jl-0-20-3-broken-image-plots/123002 "2024-11-23T20:43:55Z")

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Hello, good evening. I recently update my packages, and pluto to 20.3 and I’m getting broken image plots like this May please someone help?

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## [Help improving particle simulation on GPU](https://discourse.julialang.org/t/help-improving-particle-simulation-on-gpu/122733)

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**Author:** [@rveltz](https://discourse.julialang.org/u/rveltz)\
**Replies:** 0\
**Last updated:** [November 17, 2024, 8:23am UTC](https://discourse.julialang.org/t/help-improving-particle-simulation-on-gpu/122733 "2024-11-17T08:23:00Z")

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Hi, I am trying to simulate particles on CUDA. I have a bottleneck and I am wondering if some of you have any advice. This is a MWE of a much more sophisticated example. Basically, I have a field of probabiblities dist…

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## [Issues with continuation in BifurcationKit](https://discourse.julialang.org/t/issues-with-continuation-in-bifurcationkit/122852)

<div class="topic-metadata">

**Author:** [@mmplac14](https://discourse.julialang.org/u/mmplac14)\
**Replies:** 11\
**Last updated:** [November 23, 2024, 1:19pm UTC](https://discourse.julialang.org/t/issues-with-continuation-in-bifurcationkit/122852 "2024-11-23T13:19:25Z")

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Hi! I am new to Julia and BifurcationKit. I am trying to perform a bifurcation analysis of the Jansen-Rit model as was done by Grimbert and Faugueras but I keep running into this error when calling continuation The fun…

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## [Get vs get!](https://discourse.julialang.org/t/get-vs-get/122985)

<div class="topic-metadata">

**Author:** [@martin\_sanchez](https://discourse.julialang.org/u/martin_sanchez)\
**Replies:** 3\
**Last updated:** [November 23, 2024, 11:53am UTC](https://discourse.julialang.org/t/get-vs-get/122985 "2024-11-23T11:53:49Z")

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I do not know what could get! do to an object. Shouldn’t a get function be non-transformative of the input? I am accesing a value…

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## [Return of split](https://discourse.julialang.org/t/return-of-split/122987)

<div class="topic-metadata">

**Author:** [@martin\_sanchez](https://discourse.julialang.org/u/martin_sanchez)\
**Replies:** 6\
**Last updated:** [November 23, 2024, 11:34am UTC](https://discourse.julialang.org/t/return-of-split/122987 "2024-11-23T11:34:21Z")

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I was using split(str,separator) and it returned SubString (I verified it with typeof) and wa using the result in later functions: function instruct\_processor(db::Dict,op::String) arr=split(op," ",limit=2) print…

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## [RigidBodyDynamics.jl - Fixed joint creation not working?](https://discourse.julialang.org/t/rigidbodydynamics-jl-fixed-joint-creation-not-working/122719)

<div class="topic-metadata">

**Author:** [@RobbesU](https://discourse.julialang.org/u/RobbesU)\
**Replies:** 2\
**Last updated:** [November 23, 2024, 11:25am UTC](https://discourse.julialang.org/t/rigidbodydynamics-jl-fixed-joint-creation-not-working/122719 "2024-11-23T11:25:16Z")

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What is the correct syntax for creating a Fixed Joint, so it can be added to a Mechanism? A Revolute Joint is created by revolute\_joint = Joint("revolute\_joint", Revolute(axis) ) but a Fixed Joint I can’t get to accep…

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