# Latest

**URL:** https://discourse.julialang.org/latest.md?page=920

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

**Page:** 921

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## [Scientific formatting of y-axis using CairoMakie.jl](https://discourse.julialang.org/t/scientific-formatting-of-y-axis-using-cairomakie-jl/87463)

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**Author:** [@devanshu](https://discourse.julialang.org/u/devanshu)\
**Replies:** 3\
**Last updated:** [September 19, 2022, 3:54pm UTC](https://discourse.julialang.org/t/scientific-formatting-of-y-axis-using-cairomakie-jl/87463 "2022-09-19T15:54:09Z")

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Hi, I would like to get the formatting of my y-ticks like this How to get this using CairoMakie.jl ?

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## [\[pre-pre-ANN\] Circuits.jl](https://discourse.julialang.org/t/pre-pre-ann-circuits-jl/57625)

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**Author:** [@gustaphe](https://discourse.julialang.org/u/gustaphe)\
**Replies:** 7\
**Last updated:** [September 19, 2022, 2:48pm UTC](https://discourse.julialang.org/t/pre-pre-ann-circuits-jl/57625 "2022-09-19T14:48:35Z")

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Warning: Unregistered hobby project. I just want to see if this is something anyone else has been thinking about / wants / has input on. Circuits.jl An electrical circuit analysis tool in Julia. I’ll just show the exa…

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## [Base.Filesystem.samefile inconsistent and too restrictive?](https://discourse.julialang.org/t/base-filesystem-samefile-inconsistent-and-too-restrictive/87434)

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**Author:** [@martin.auer](https://discourse.julialang.org/u/martin.auer)\
**Replies:** 3\
**Last updated:** [September 19, 2022, 2:21pm UTC](https://discourse.julialang.org/t/base-filesystem-samefile-inconsistent-and-too-restrictive/87434 "2022-09-19T14:21:36Z")

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Hi, I am toying around with a simple struct type that contains a file system entry’s path and its StatStruct. Defining stat(x::FsEntry) = x.st then allows using much of Base.Filesystem’s API without repeated calls to th…

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## [Missing code/fences button in Discourse editor](https://discourse.julialang.org/t/missing-code-fences-button-in-discourse-editor/87460)

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**Author:** [@DNF](https://discourse.julialang.org/u/DNF)\
**Replies:** 8\
**Last updated:** [September 19, 2022, 1:18pm UTC](https://discourse.julialang.org/t/missing-code-fences-button-in-discourse-editor/87460 "2022-09-19T13:18:36Z")

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What happened with the “code button” in the Discourse editor? The one which inserts single or triple backticks. Suddenly, yesterday, it was gone, and my formatting menu just looks like this: There used to be a button,…

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## [Gradient vector of a matrix of geographical extent](https://discourse.julialang.org/t/gradient-vector-of-a-matrix-of-geographical-extent/87318)

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**Author:** [@ManuelFossa](https://discourse.julialang.org/u/ManuelFossa)\
**Replies:** 3\
**Last updated:** [September 19, 2022, 12:48pm UTC](https://discourse.julialang.org/t/gradient-vector-of-a-matrix-of-geographical-extent/87318 "2022-09-19T12:48:24Z")

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I have a geographical matrix M of dimensions nLat=181 and nLon=221 , with lats = 30:0.25:90 and lons=-30:0.25:25. I want to compute the gradient vector of M w.r.t to lats , lons. I have tried ForwardDiff , Iterations …

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## [IRTools need help: purge unused arguments from argument list of a function](https://discourse.julialang.org/t/irtools-need-help-purge-unused-arguments-from-argument-list-of-a-function/86431)

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**Author:** [@Lian\_Yunlong](https://discourse.julialang.org/u/Lian_Yunlong)\
**Replies:** 1\
**Last updated:** [August 27, 2022, 2:02pm UTC](https://discourse.julialang.org/t/irtools-need-help-purge-unused-arguments-from-argument-list-of-a-function/86431 "2022-08-27T14:02:20Z")

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Hello, I want to implement a method called “purge\_function\_args”, which remove the n’th argument (which is known to be dummy) from the function arg list. I need a kickstarter for the application of IRTools.jl package. C…

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## [Transform CodeInfo of a function to get a new function by purging unused args from its arg list](https://discourse.julialang.org/t/transform-codeinfo-of-a-function-to-get-a-new-function-by-purging-unused-args-from-its-arg-list/87459)

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**Author:** [@Lian\_Yunlong](https://discourse.julialang.org/u/Lian_Yunlong)\
**Replies:** 1\
**Last updated:** [September 19, 2022, 10:31am UTC](https://discourse.julialang.org/t/transform-codeinfo-of-a-function-to-get-a-new-function-by-purging-unused-args-from-its-arg-list/87459 "2022-09-19T10:31:13Z")

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Hello, I wish to purge an unused argument from the arglist of a function. Following CodeTransformation.jl, I wrote a function to do this task: function assign\_purge\_argument!(@nospecialize(p::Pair{\<:Function,\<:Function…

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## [Metaprogramming: macro creating types](https://discourse.julialang.org/t/metaprogramming-macro-creating-types/87439)

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**Author:** [@davidavdav](https://discourse.julialang.org/u/davidavdav)\
**Replies:** 2\
**Last updated:** [September 19, 2022, 8:52am UTC](https://discourse.julialang.org/t/metaprogramming-macro-creating-types/87439 "2022-09-19T08:52:12Z")

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Hi, I’ve been struggling with making a macro that will define a new wrapper type for me, with some minimal functions to make the wrapper type function more/less the same as the type it waps. For now have the minimal wr…

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## [How to you call this julia feature?](https://discourse.julialang.org/t/how-to-you-call-this-julia-feature/87413)

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**Author:** [@schlichtanders](https://discourse.julialang.org/u/schlichtanders)\
**Replies:** 6\
**Last updated:** [September 18, 2022, 8:03am UTC](https://discourse.julialang.org/t/how-to-you-call-this-julia-feature/87413 "2022-09-18T08:03:51Z")

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I am using julia for 5+ years and today I learned about a mind-blowing feature which I wasn’t aware that it exists. julia\> function test\_internal\_state(st) function update\_st() st = st + 1 nothing …

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## [Using JuliaMath/Interpolations.jl on an image](https://discourse.julialang.org/t/using-juliamath-interpolations-jl-on-an-image/7113)

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**Author:** [@mcbaron](https://discourse.julialang.org/u/mcbaron)\
**Replies:** 8\
**Last updated:** [September 19, 2022, 6:18am UTC](https://discourse.julialang.org/t/using-juliamath-interpolations-jl-on-an-image/7113 "2022-09-19T06:18:39Z")

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Hello all, I’m struggling with an OutOfMemory() error while trying to index into an interpolation object with an image size set of indices. I know enough to think that this means that there is probably something wrong w…

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## [Why isn't JuMP.register named register!](https://discourse.julialang.org/t/why-isnt-jump-register-named-register/87456)

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**Author:** [@jar1](https://discourse.julialang.org/u/jar1)\
**Replies:** 3\
**Last updated:** [September 19, 2022, 5:57am UTC](https://discourse.julialang.org/t/why-isnt-jump-register-named-register/87456 "2022-09-19T05:57:17Z")

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register modifies its argument model, so the function would normally end in !. Why isn’t this function named register!?

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## [Tabular MDP/Q-learning solver: Reward Matrix R(s, a, s') vs. R(s, a)](https://discourse.julialang.org/t/tabular-mdp-q-learning-solver-reward-matrix-r-s-a-s-vs-r-s-a/87457)

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**Author:** [@Richard\_Wright](https://discourse.julialang.org/u/Richard_Wright)\
**Replies:** 0\
**Last updated:** [September 19, 2022, 4:52am UTC](https://discourse.julialang.org/t/tabular-mdp-q-learning-solver-reward-matrix-r-s-a-s-vs-r-s-a/87457 "2022-09-19T04:52:51Z")

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Hello Folks, I am using the POMDP package along with the TabularTDLearning package In the first part of the problem I worked out a 3D transition matrix T(s’, a, s) and a 2D reward matrix R(s, a). Then formulated it as …

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## [Add columns to DataFrame](https://discourse.julialang.org/t/add-columns-to-dataframe/49305)

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**Author:** [@Smith](https://discourse.julialang.org/u/Smith)\
**Replies:** 5\
**Last updated:** [September 19, 2022, 4:47am UTC](https://discourse.julialang.org/t/add-columns-to-dataframe/49305 "2022-09-19T04:47:41Z")

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I want to add columns to a dataframe iteratively in a loop and assign them a name. The code below seems to add one column to the dataframe containing value of p at the last iteration and name of the column appears as col…

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## [Broadcast question](https://discourse.julialang.org/t/broadcast-question/87210)

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**Author:** [@Lincoln\_Hannah](https://discourse.julialang.org/u/Lincoln_Hannah)\
**Replies:** 2\
**Last updated:** [September 19, 2022, 3:09am UTC](https://discourse.julialang.org/t/broadcast-question/87210 "2022-09-19T03:09:04Z")

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I got this off CUDA.jl…/test/texture.jl (altered a bit) Tex = @pipe rand(Float32,10) |\> CuTextureArray |\> CuTexture(\_, interpolation=CUDA.LinearInterpolation()) Idx = rand(Float32,10) .+1 |\> CuArray …

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## [Pre-allocate for findall](https://discourse.julialang.org/t/pre-allocate-for-findall/87454)

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**Author:** [@MacKenzieHnC](https://discourse.julialang.org/u/MacKenzieHnC)\
**Replies:** 16\
**Last updated:** [September 19, 2022, 1:24am UTC](https://discourse.julialang.org/t/pre-allocate-for-findall/87454 "2022-09-19T01:24:43Z")

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I am absolutely sure something like this has been asked before but I cannot for the life of me find it. I’m currently working on a memory- and speed-efficient way to access the first 1 billion primes as part of a differ…

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## [Define map, filter, ... also as functionals](https://discourse.julialang.org/t/define-map-filter-also-as-functionals/87401)

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**Author:** [@ludwig-austermann](https://discourse.julialang.org/u/ludwig-austermann)\
**Replies:** 10\
**Last updated:** [September 19, 2022, 12:16am UTC](https://discourse.julialang.org/t/define-map-filter-also-as-functionals/87401 "2022-09-19T00:16:27Z")

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Hey all, I like the pipelining syntax, but I often encounter the problem that one has to write code like this: rand(10) |\> x -\> filter(\<=(0.5), x) I see that map, filter, accumulate, findfirst etc. all take a minimum …

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## [How do I make dynamically named symbols?](https://discourse.julialang.org/t/how-do-i-make-dynamically-named-symbols/87450)

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**Author:** [@AwesomeQuest](https://discourse.julialang.org/u/AwesomeQuest)\
**Replies:** 4\
**Last updated:** [September 18, 2022, 11:54pm UTC](https://discourse.julialang.org/t/how-do-i-make-dynamically-named-symbols/87450 "2022-09-18T23:54:50Z")

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I’m making a function that calculates the equation for the error of a given symbolic equation. using Symbolics function findErrorFromSym(sym) vars = Symbolics.get\_variables(sym) @variables varErrs\[eachindex(vars…

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## [What is this for syntax called?](https://discourse.julialang.org/t/what-is-this-for-syntax-called/87445)

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**Author:** [@AwesomeQuest](https://discourse.julialang.org/u/AwesomeQuest)\
**Replies:** 9\
**Last updated:** [September 18, 2022, 10:18pm UTC](https://discourse.julialang.org/t/what-is-this-for-syntax-called/87445 "2022-09-18T22:18:53Z")

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\[ i for i in 1:10\] What is this called and how exactly does it work? I get how it’s used (wonderfully convenient), but what is this exactly equivalent to? What and how does it allocate? When should and shouldn’t I use…

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## [Univariate feature selection](https://discourse.julialang.org/t/univariate-feature-selection/87414)

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**Author:** [@lucasmsoares96](https://discourse.julialang.org/u/lucasmsoares96)\
**Replies:** 1\
**Last updated:** [September 18, 2022, 9:07pm UTC](https://discourse.julialang.org/t/univariate-feature-selection/87414 "2022-09-18T21:07:37Z")

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I’m having trouble finding a feature selection using Univariate feature selection in Julia. In scikit-learn this is possible as follows: from sklearn.datasets import load\_iris from sklearn.feature\_selection import Selec…

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## [Problem interrupting kernel in Jupyter](https://discourse.julialang.org/t/problem-interrupting-kernel-in-jupyter/75666)

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**Author:** [@pafloxy](https://discourse.julialang.org/u/pafloxy)\
**Replies:** 2\
**Last updated:** [September 18, 2022, 7:30pm UTC](https://discourse.julialang.org/t/problem-interrupting-kernel-in-jupyter/75666 "2022-09-18T19:30:01Z")

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The problem is that whenever I’m interrupting the kernel manually in Jupyter the kernel doesn’t really stop and keeps on runnig! Is there a way to get around this issue ?

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## [Fetching progress: why does it almost always stall at 99.9%?](https://discourse.julialang.org/t/fetching-progress-why-does-it-almost-always-stall-at-99-9/87360)

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**Author:** [@wsshin](https://discourse.julialang.org/u/wsshin)\
**Replies:** 7\
**Last updated:** [September 18, 2022, 5:55pm UTC](https://discourse.julialang.org/t/fetching-progress-why-does-it-almost-always-stall-at-99-9/87360 "2022-09-18T17:55:33Z")

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When I install Julia packages, sometimes fetching occurs. And when fetching occurs, a lot of times it progresses quite fast until 99.9 % (within a few seconds), but then it stalls there for several minutes: (@v1.8) pkg\>…

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## [Should transpose of a Vector be a Matrix?](https://discourse.julialang.org/t/should-transpose-of-a-vector-be-a-matrix/87444)

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**Author:** [@owiecc](https://discourse.julialang.org/u/owiecc)\
**Replies:** 3\
**Last updated:** [September 18, 2022, 4:47pm UTC](https://discourse.julialang.org/t/should-transpose-of-a-vector-be-a-matrix/87444 "2022-09-18T16:47:33Z")

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As Julia has a true 1D vector data type, shouldn’t the transpose of a Vector just be a Vector (essentially an identity operation)? See Conor Hoekstra’s comments in APL vs BQN vs J vs Q vs NumPy vs Julia vs R - YouTube I…

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## [Peak memory usage with \`getrusage\`](https://discourse.julialang.org/t/peak-memory-usage-with-getrusage/87443)

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**Author:** [@luciano-drozda](https://discourse.julialang.org/u/luciano-drozda)\
**Replies:** 0\
**Last updated:** [September 18, 2022, 4:18pm UTC](https://discourse.julialang.org/t/peak-memory-usage-with-getrusage/87443 "2022-09-18T16:18:58Z")

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Peak memory usage could be measured by ccall to getrusage, right ? I’m obtaining the value of 0 KB when calling run\_mtest("create\_strings", () -\> mtest\_create\_strings()) from the example here. Should it return a differ…

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## [What does \`export Foo\` do when there are multiple \`Foo\`'s?](https://discourse.julialang.org/t/what-does-export-foo-do-when-there-are-multiple-foo-s/86579)

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**Author:** [@Ross\_Boylan](https://discourse.julialang.org/u/Ross_Boylan)\
**Replies:** 6\
**Last updated:** [September 18, 2022, 4:18pm UTC](https://discourse.julialang.org/t/what-does-export-foo-do-when-there-are-multiple-foo-s/86579 "2022-09-18T16:18:48Z")

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export works on names, but sometimes there are several objects with the same name. Which of them are exported? I’m wondering about this because I have struct Foo and a constructor function Foo. The discussion of keywo…

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## [How to count the number of categories present in a column of a DataFrame](https://discourse.julialang.org/t/how-to-count-the-number-of-categories-present-in-a-column-of-a-dataframe/33244)

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**Author:** [@philc](https://discourse.julialang.org/u/philc)\
**Replies:** 8\
**Last updated:** [September 18, 2022, 4:01pm UTC](https://discourse.julialang.org/t/how-to-count-the-number-of-categories-present-in-a-column-of-a-dataframe/33244 "2022-09-18T16:01:18Z")

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Hello, In a dataframe with columns :A, :B, :C where :B contains categorical data, I would like to count the number of categories present in the different subdataframes obtained through groupby(df,:A), and finally gettin…

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## [Print the MDP q-matrix](https://discourse.julialang.org/t/print-the-mdp-q-matrix/87425)

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**Author:** [@Richard\_Wright](https://discourse.julialang.org/u/Richard_Wright)\
**Replies:** 4\
**Last updated:** [September 18, 2022, 3:26pm UTC](https://discourse.julialang.org/t/print-the-mdp-q-matrix/87425 "2022-09-18T15:26:06Z")

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Hello, Need some help please, with printing out the Q-matrix when using MDP and Tabular TD learning. I have been able to formulate the MDP and the solver and solve the policy. The code is mdp = TabularMDP(T, R, Discou…

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## [Change the name of Julia to JULai](https://discourse.julialang.org/t/change-the-name-of-julia-to-julai/87407)

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**Author:** [@NickW3101](https://discourse.julialang.org/u/NickW3101)\
**Replies:** 18\
**Last updated:** [September 18, 2022, 2:54pm UTC](https://discourse.julialang.org/t/change-the-name-of-julia-to-julai/87407 "2022-09-18T14:54:54Z")

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The word Julia is hard for Google searches. JULai wouldn’t be confused with anything else. Edit: Scrap JULai as the name suggestion but a completely unique 1 to 2 syllable word

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## [How to point Julia to the correct package location?](https://discourse.julialang.org/t/how-to-point-julia-to-the-correct-package-location/87442)

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**Author:** [@Brad\_Carman](https://discourse.julialang.org/u/Brad_Carman)\
**Replies:** 0\
**Last updated:** [September 18, 2022, 2:27pm UTC](https://discourse.julialang.org/t/how-to-point-julia-to-the-correct-package-location/87442 "2022-09-18T14:27:07Z")

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If I’ve installed and loaded a package, and then in the same session develop said package, I would expect that pkgdir(\<developed package\>) would point to the developed package path. This is not my experience, the direct…

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## [L strings not working in Makie](https://discourse.julialang.org/t/l-strings-not-working-in-makie/87366)

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**Author:** [@Thomas\_Mikaelsen](https://discourse.julialang.org/u/Thomas_Mikaelsen)\
**Replies:** 6\
**Last updated:** [September 18, 2022, 2:05pm UTC](https://discourse.julialang.org/t/l-strings-not-working-in-makie/87366 "2022-09-18T14:05:59Z")

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Hello. First post on this forum so I apologize if I fall short of the conventions. I can’t get L strings to work with Makie on Jupyter Notebook. I just installed Makie, CairoMakie and MakieTeX. I couldn’t get my own exa…

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## [Allocation during construction of compile-time sized structure](https://discourse.julialang.org/t/allocation-during-construction-of-compile-time-sized-structure/87435)

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**Author:** [@user664303](https://discourse.julialang.org/u/user664303)\
**Replies:** 1\
**Last updated:** [September 18, 2022, 12:25pm UTC](https://discourse.julialang.org/t/allocation-during-construction-of-compile-time-sized-structure/87435 "2022-09-18T12:25:04Z")

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I have a simple, immutable structure that wraps a statically sized matrix. When I construct it with an initialization value, it causes a memory allocation. I expected there to be no such allocation. Should there be an al…

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