# Latest

**URL:** https://discourse.julialang.org/latest.md?page=1340

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

**Page:** 1341

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## [ForwardDiff caches usage](https://discourse.julialang.org/t/forwarddiff-caches-usage/64058)

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**Author:** [@jdlara-berkeley](https://discourse.julialang.org/u/jdlara-berkeley)\
**Replies:** 5\
**Last updated:** [July 5, 2021, 4:07pm UTC](https://discourse.julialang.org/t/forwarddiff-caches-usage/64058 "2021-07-05T16:07:06Z")

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I have been trying to implement a cache correctly for ForwardDiff similar to DiffEqCache without too much success. My final objective is to have a Jacobian function of the system that we can reuse in multiple steps sinc…

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## [How do I best convert a nested named tuple to a nested struct?](https://discourse.julialang.org/t/how-do-i-best-convert-a-nested-named-tuple-to-a-nested-struct/64001)

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**Author:** [@Joris\_Pinkse](https://discourse.julialang.org/u/Joris_Pinkse)\
**Replies:** 5\
**Last updated:** [July 5, 2021, 4:03pm UTC](https://discourse.julialang.org/t/how-do-i-best-convert-a-nested-named-tuple-to-a-nested-struct/64001 "2021-07-05T16:03:51Z")

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The code below contains two examples: the first example works, the second one doesn’t. The first example creates a struct, then writes it to an arrow file (which converts it to a named tuple along the way). Reading it …

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## [Parameter manipulation while solving ODE](https://discourse.julialang.org/t/parameter-manipulation-while-solving-ode/64082)

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**Author:** [@AhmedAlreweny](https://discourse.julialang.org/u/AhmedAlreweny)\
**Replies:** 3\
**Last updated:** [July 5, 2021, 2:55pm UTC](https://discourse.julialang.org/t/parameter-manipulation-while-solving-ode/64082 "2021-07-05T14:55:47Z")

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Hi, I am trying to solve an optimal control problem on the following form of Lorenz system: function lorenz(du, u, p, t) theta = p du\[1\] = 10.0 \* (u\[2\] - u\[1\]) + theta\[1\] du\[2\] = u\[1\] \* (28.0 - (u\[3\])) - u\[…

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## [Unpacking semi-structured binary stream](https://discourse.julialang.org/t/unpacking-semi-structured-binary-stream/64070)

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**Author:** [@jling](https://discourse.julialang.org/u/jling)\
**Replies:** 4\
**Last updated:** [July 5, 2021, 2:23pm UTC](https://discourse.julialang.org/t/unpacking-semi-structured-binary-stream/64070 "2021-07-05T14:23:22Z")

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Continuation of: say we have two similar but slightly different struct: struct TKey32 \<: TKey fNbytes::Int32 fVersion::Int16 ... fSeekKey::Int32 fSeekPdir::Int32 fClassName::String fName::S…

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## [\`@code\_native\` shows an algorithm that appears to be O(N), but benchmarking suggests that it's actually O(1)](https://discourse.julialang.org/t/code-native-shows-an-algorithm-that-appears-to-be-o-n-but-benchmarking-suggests-that-its-actually-o-1/63834)

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**Author:** [@seamsay](https://discourse.julialang.org/u/seamsay)\
**Replies:** 12\
**Last updated:** [July 5, 2021, 2:16pm UTC](https://discourse.julialang.org/t/code-native-shows-an-algorithm-that-appears-to-be-o-n-but-benchmarking-suggests-that-its-actually-o-1/63834 "2021-07-05T14:16:22Z")

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I hope this is an OK category to put this under, I couldn’t see anything that matched better :grimacing: I’m trying to get better at reading assembly output by looking at some interesting optimisations. I’m currently lo…

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## [Qksqt incoming network connections](https://discourse.julialang.org/t/qksqt-incoming-network-connections/61888)

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**Author:** [@hendri54](https://discourse.julialang.org/u/hendri54)\
**Replies:** 2\
**Last updated:** [July 5, 2021, 1:28pm UTC](https://discourse.julialang.org/t/qksqt-incoming-network-connections/61888 "2021-07-05T13:28:38Z")

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When I plot with the GR backend (Plots.jl) a popup window asks Do you want the application “gksqt.app” to accept incoming network connections? This appears each time I plot. How can I avoid this? julia\> versioninfo() …

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## [REPL in VS Code stalling overnight](https://discourse.julialang.org/t/repl-in-vs-code-stalling-overnight/63976)

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**Author:** [@Bardo](https://discourse.julialang.org/u/Bardo)\
**Replies:** 7\
**Last updated:** [July 5, 2021, 1:16pm UTC](https://discourse.julialang.org/t/repl-in-vs-code-stalling-overnight/63976 "2021-07-05T13:16:49Z")

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Leaving the session open, the REPL window regularly freezes with an empty screen and the cursor about in the middle. Any remedy? (Win10, latest VS Code and Julia)

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## [Where can I learn how to read the output of \`@code\_llvm\`?](https://discourse.julialang.org/t/where-can-i-learn-how-to-read-the-output-of-code-llvm/64075)

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**Author:** [@SteffenPL](https://discourse.julialang.org/u/SteffenPL)\
**Replies:** 4\
**Last updated:** [July 5, 2021, 1:01pm UTC](https://discourse.julialang.org/t/where-can-i-learn-how-to-read-the-output-of-code-llvm/64075 "2021-07-05T13:01:18Z")

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I often ask myself which optimisations the Julia compiler does and find the answer in the output of @code\_llvm. The tutorials (I found so far) on LLVM IR are all about how to write a compiler. Is there a quicker way to …

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## [How to stop a process started with \`@spawnat :any\`](https://discourse.julialang.org/t/how-to-stop-a-process-started-with-spawnat-any/64023)

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**Author:** [@AtsushiSakai](https://discourse.julialang.org/u/AtsushiSakai)\
**Replies:** 2\
**Last updated:** [July 5, 2021, 12:04pm UTC](https://discourse.julialang.org/t/how-to-stop-a-process-started-with-spawnat-any/64023 "2021-07-05T12:04:49Z")

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Suppose I start a parallel task with: future = @spawnat :any do\_very\_long\_time\_process() How can I stop the process using the future? There is Distributed.interrupt, but it needs pid. In other words, how can I get pi…

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## [Question in Strings.ipynb](https://discourse.julialang.org/t/question-in-strings-ipynb/64074)

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**Author:** [@Paresh](https://discourse.julialang.org/u/Paresh)\
**Replies:** 2\
**Last updated:** [July 5, 2021, 12:24pm UTC](https://discourse.julialang.org/t/question-in-strings-ipynb/64074 "2021-07-05T12:24:38Z")

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Hello, I am new to Julia. I have a question in Strings.ipynb in Intro to Julia. Exercise 2.1 part (b), what is the exponentiation operator in Julia? How can I produce “hi” 1000 times by using \* under the hood? Please gi…

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## [How to know when a task is done?](https://discourse.julialang.org/t/how-to-know-when-a-task-is-done/63978)

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**Author:** [@singularitti](https://discourse.julialang.org/u/singularitti)\
**Replies:** 10\
**Last updated:** [July 5, 2021, 11:23am UTC](https://discourse.julialang.org/t/how-to-know-when-a-task-is-done/63978 "2021-07-05T11:23:16Z")

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If I create a Task using @async, and want to do something (like changing some status) immediately after that task is done, how do I do that? I guess istaskdone can only let me check everytime manually. I don’t quite unde…

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## [Regresion: Eigvals of bigfloat symmetric matrices does not work anymore](https://discourse.julialang.org/t/regresion-eigvals-of-bigfloat-symmetric-matrices-does-not-work-anymore/63947)

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**Author:** [@lrnv](https://discourse.julialang.org/u/lrnv)\
**Replies:** 2\
**Last updated:** [July 5, 2021, 8:20am UTC](https://discourse.julialang.org/t/regresion-eigvals-of-bigfloat-symmetric-matrices-does-not-work-anymore/63947 "2021-07-05T08:20:05Z")

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Hi, I have troubles to get eigenvalues of Symmetric matrices. Here is an example : julia\> X = big.(rand(10,10)); julia\> X = X .+ X'; julia\> eigvals(X) ERROR: UndefVarError: eigvals not defined Stacktrace: \[1\] top-le…

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## [Inaccurate values generated by loop compared to hand calculations. Can't find my mistake](https://discourse.julialang.org/t/inaccurate-values-generated-by-loop-compared-to-hand-calculations-cant-find-my-mistake/64060)

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**Author:** [@Mark\_Williams](https://discourse.julialang.org/u/Mark_Williams)\
**Replies:** 1\
**Last updated:** [July 5, 2021, 6:41am UTC](https://discourse.julialang.org/t/inaccurate-values-generated-by-loop-compared-to-hand-calculations-cant-find-my-mistake/64060 "2021-07-05T06:41:42Z")

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Firstly, I apologise for asking what looks like such a silly question. Any help will be very welcome. I have a function which uses a double loop to compute the entries of a matrix L. I know the matrix values from a paper…

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## [Using casadi from Julia](https://discourse.julialang.org/t/using-casadi-from-julia/63988)

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**Author:** [@adityac](https://discourse.julialang.org/u/adityac)\
**Replies:** 11\
**Last updated:** [July 5, 2021, 2:47am UTC](https://discourse.julialang.org/t/using-casadi-from-julia/63988 "2021-07-05T02:47:25Z")

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I am trying to use Casadi from Julia using the opti stack. I am trying to do this using PyCall. I get an error when I use the following code: opti = casadi.Opti(); x = opti.variable(); y = opti.variable(); opti.minimi…

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## [My Brain Is Hard-Wired Against ==; Help Me, Julia](https://discourse.julialang.org/t/my-brain-is-hard-wired-against-help-me-julia/63532)

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**Author:** [@blackeneth](https://discourse.julialang.org/u/blackeneth)\
**Replies:** 97\
**Last updated:** [July 5, 2021, 1:38am UTC](https://discourse.julialang.org/t/my-brain-is-hard-wired-against-help-me-julia/63532 "2021-07-05T01:38:23Z")

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Equality in Julia is tested using == x = 5 if x == 5 println("x is five!") end However, a mistake I make all the time, even several times a day, over a period of several years, is to use = instead of == : x = 5 if x …

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## [Julia v1.7.0-beta2 is now available](https://discourse.julialang.org/t/julia-v1-7-0-beta2-is-now-available/63408)

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**Author:** [@ararslan](https://discourse.julialang.org/u/ararslan)\
**Replies:** 21\
**Last updated:** [July 4, 2021, 9:16pm UTC](https://discourse.julialang.org/t/julia-v1-7-0-beta2-is-now-available/63408 "2021-07-04T21:16:23Z")

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The Julia developers are pleased to announce that Julia v1.7.0 is now in beta, and binaries for v1.7.0-beta2 are available now. You can get them at https://julialang.org/downloads in the “upcoming release” section for ma…

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## [Applying Machine learning models to Diabetes dataset using MLJ.jl packages](https://discourse.julialang.org/t/applying-machine-learning-models-to-diabetes-dataset-using-mlj-jl-packages/64047)

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**Author:** [@Maria\_Brown](https://discourse.julialang.org/u/Maria_Brown)\
**Replies:** 2\
**Last updated:** [July 4, 2021, 8:45pm UTC](https://discourse.julialang.org/t/applying-machine-learning-models-to-diabetes-dataset-using-mlj-jl-packages/64047 "2021-07-04T20:45:56Z")

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\*\*Hello, \*\* Please I have this diabetes dataset which i have cleaned using Altery designer, and I would love to build ML models(Random Forest tree, Logistic regression, KNN, Support Vector Machine and Naive Baye algorit…

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## [MDPs simple program which:](https://discourse.julialang.org/t/mdps-simple-program-which/64048)

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**Author:** [@Ernstkandombo](https://discourse.julialang.org/u/Ernstkandombo)\
**Replies:** 1\
**Last updated:** [July 4, 2021, 8:17pm UTC](https://discourse.julialang.org/t/mdps-simple-program-which/64048 "2021-07-04T20:17:42Z")

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1.capture and store a Markov decision process (MDP) at runtime; 2. given a policy, evaluate the policy and improve it to get a solution.

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## [Should someone create a wikipedia page for Jeff?](https://discourse.julialang.org/t/should-someone-create-a-wikipedia-page-for-jeff/15400)

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**Author:** [@djsegal](https://discourse.julialang.org/u/djsegal)\
**Replies:** 13\
**Last updated:** [July 4, 2021, 7:41pm UTC](https://discourse.julialang.org/t/should-someone-create-a-wikipedia-page-for-jeff/15400 "2021-07-04T19:41:06Z")

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I mean it’s not my circus, but it seems kind of weird that Jeff’s name doesn’t show up when you google Julia?

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## [\`CUDA.quicksort\` is not faster than CPU radixsort](https://discourse.julialang.org/t/cuda-quicksort-is-not-faster-than-cpu-radixsort/64036)

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**Author:** [@xiaodai](https://discourse.julialang.org/u/xiaodai)\
**Replies:** 3\
**Last updated:** [July 4, 2021, 7:53pm UTC](https://discourse.julialang.org/t/cuda-quicksort-is-not-faster-than-cpu-radixsort/64036 "2021-07-04T19:53:08Z")

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Here’s my testing code using SortingAlgorithms a32 = rand(Float32, 10\_000\_000) @benchmark sort($a32, alg=RadixSort) using CUDA cua32 = cu(a32) @benchmark CUDA.@sync sort($cua32) So the on my GPU which is RT…

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## [Announcing Julia Gender Inclusive](https://discourse.julialang.org/t/announcing-julia-gender-inclusive/63702)

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**Author:** [@Xuan](https://discourse.julialang.org/u/Xuan)\
**Replies:** 8\
**Last updated:** [July 4, 2021, 6:57pm UTC](https://discourse.julialang.org/t/announcing-julia-gender-inclusive/63702 "2021-07-04T18:57:34Z")

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For several years now, members of the Julia community have noted that our community is not as diverse as it could be. While the community strives to be welcoming, diverse, and inclusive towards people from all background…

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## [Problem with Travis CI](https://discourse.julialang.org/t/problem-with-travis-ci/64046)

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**Author:** [@RJDennis](https://discourse.julialang.org/u/RJDennis)\
**Replies:** 2\
**Last updated:** [July 4, 2021, 6:50pm UTC](https://discourse.julialang.org/t/problem-with-travis-ci/64046 "2021-07-04T18:50:20Z")

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In the last couple of days, commits I make to my registered packages do not trigger Travis CI. I have it set up on Github to point to travis-ci.com, which I believe is correct. Is anyone else having this problem and/or…

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## [Gnuplot.jl + Windows 10: mouse can't zoom in/out](https://discourse.julialang.org/t/gnuplot-jl-windows-10-mouse-cant-zoom-in-out/64038)

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**Author:** [@Inna](https://discourse.julialang.org/u/Inna)\
**Replies:** 4\
**Last updated:** [July 4, 2021, 6:31pm UTC](https://discourse.julialang.org/t/gnuplot-jl-windows-10-mouse-cant-zoom-in-out/64038 "2021-07-04T18:31:04Z")

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Dear all, I have Windows 10 64-bit, gnuplot Version 5.4 patchlevel 1 (terminal qt) and Julia 1.6.1 with Gnuplot.jl v1.4.0 . When i use gnuplot without julia: gnuplot\> plot sin(x) i get the plot fine. Mouse can zoom …

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## [Advanced submodule: Pattern or Anti-pattern?](https://discourse.julialang.org/t/advanced-submodule-pattern-or-anti-pattern/63894)

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**Author:** [@DrChainsaw](https://discourse.julialang.org/u/DrChainsaw)\
**Replies:** 6\
**Last updated:** [July 4, 2021, 5:48pm UTC](https://discourse.julialang.org/t/advanced-submodule-pattern-or-anti-pattern/63894 "2021-07-04T17:48:12Z")

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The package in question has a handful (about 10) simple ‘main API’ functions. Most of those functions follow the pattern of examining the user input a bit, then selecting some combination of more generic functions to cal…

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## [Pkg.gc() results in error](https://discourse.julialang.org/t/pkg-gc-results-in-error/63972)

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**Author:** [@ParadaCarleton](https://discourse.julialang.org/u/ParadaCarleton)\
**Replies:** 7\
**Last updated:** [July 4, 2021, 5:33pm UTC](https://discourse.julialang.org/t/pkg-gc-results-in-error/63972 "2021-07-04T17:33:17Z")

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julia\> import Pkg julia\> Pkg.gc() ERROR: SystemError: opening file "/usr/share/julia/logs/manifest\_usage.toml": Permission denied Stacktrace: \[1\] systemerror(p::String, errno::Int32; extrainfo::Nothing) @ Base ./e…

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## [How to have latex-like shortcuts in other documents also in VS Code?](https://discourse.julialang.org/t/how-to-have-latex-like-shortcuts-in-other-documents-also-in-vs-code/64044)

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**Author:** [@sylvaticus](https://discourse.julialang.org/u/sylvaticus)\
**Replies:** 1\
**Last updated:** [July 4, 2021, 5:06pm UTC](https://discourse.julialang.org/t/how-to-have-latex-like-shortcuts-in-other-documents-also-in-vs-code/64044 "2021-07-04T17:06:37Z")

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Hello, in Atom I am used to benefit of Juno latex-like unicode also in non-julia documents, like in markdon documents that I write (and visualise under “markdown preview plus”) when I don’t want bother for full Latex equ…

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## [How to save .string, .float data in .csv at the same time?](https://discourse.julialang.org/t/how-to-save-string-float-data-in-csv-at-the-same-time/64029)

<div class="topic-metadata">

**Author:** [@Sawyer\_Zhou](https://discourse.julialang.org/u/Sawyer_Zhou)\
**Replies:** 4\
**Last updated:** [July 4, 2021, 3:34pm UTC](https://discourse.julialang.org/t/how-to-save-string-float-data-in-csv-at-the-same-time/64029 "2021-07-04T15:34:54Z")

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I want to save the float and string data in CSV at the same time, here is a mini-case of my code: using CSV for i in 1:10 x = "test"; y = rand(1) CSV.write("out.csv", (x = x, y = y), append = true) end I w…

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## [Makie: Płot a number line](https://discourse.julialang.org/t/makie-plot-a-number-line/64032)

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**Author:** [@mschauer](https://discourse.julialang.org/u/mschauer)\
**Replies:** 1\
**Last updated:** [July 4, 2021, 2:10pm UTC](https://discourse.julialang.org/t/makie-plot-a-number-line/64032 "2021-07-04T14:10:47Z")

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I just need a number line, like so Can I free that from the Axis object?

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## [Loop doesn't work](https://discourse.julialang.org/t/loop-doesnt-work/64035)

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**Author:** [@shajeenahamed](https://discourse.julialang.org/u/shajeenahamed)\
**Replies:** 2\
**Last updated:** [July 4, 2021, 12:55pm UTC](https://discourse.julialang.org/t/loop-doesnt-work/64035 "2021-07-04T12:55:54Z")

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I have just started learning julia, but it kind of stuck in loop. Below code does not work, but syntax seems to be good. any idea? k = 0 while k \< 10 k += 1 println(k) end Error ERROR: LoadError: UndefVarError…

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## [Unable to open IJulia notebook](https://discourse.julialang.org/t/unable-to-open-ijulia-notebook/64021)

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**Author:** [@narayan](https://discourse.julialang.org/u/narayan)\
**Replies:** 0\
**Last updated:** [July 4, 2021, 5:47am UTC](https://discourse.julialang.org/t/unable-to-open-ijulia-notebook/64021 "2021-07-04T05:47:35Z")

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When I run IJulia.notebook() command I get the following text, and it doesn’t open the notebook. \[ Info: running setenv('C:\\Users\\Narayan\\.julia\\conda\\3\\Scripts\\jupyter.exe' notebook,\[“PATH=C:\\Users\\Narayan\\.julia\\conda…

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