# General Usage

**URL:** https://discourse.julialang.org/c/usage/6.md?page=311

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**Page:** 312

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## [Build an URI with query parameters](https://discourse.julialang.org/t/build-an-uri-with-query-parameters/96556)

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**Author:** [@oliviermilla](https://discourse.julialang.org/u/oliviermilla)\
**Replies:** 2\
**Last updated:** [March 24, 2023, 6:58pm UTC](https://discourse.julialang.org/t/build-an-uri-with-query-parameters/96556 "2023-03-24T18:58:54Z")

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Using URIs 1.4.2 How to generate URI with query parameters? URI("http://www.example.com"; query=Dict("a" =\> "b")) ERROR: MethodError: no method matching URI(::String; query=Dict("a" =\> "b")) Closest candidates are: …

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## [Behavior of threads](https://discourse.julialang.org/t/behavior-of-threads/95769)

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**Author:** [@PetrKryslUCSD](https://discourse.julialang.org/u/PetrKryslUCSD)\
**Replies:** 33\
**Last updated:** [March 24, 2023, 5:34pm UTC](https://discourse.julialang.org/t/behavior-of-threads/95769 "2023-03-24T17:34:29Z")

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The manual states: The @threads macro executes the loop body in an unspecified order and potentially concurrently. It does not specify the exact assignments of the tasks and the worker threads. The assignments can be d…

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## [Data property editor not working in GenieBuilder](https://discourse.julialang.org/t/data-property-editor-not-working-in-geniebuilder/96551)

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**Author:** [@Christopher\_Fisher](https://discourse.julialang.org/u/Christopher_Fisher)\
**Replies:** 0\
**Last updated:** [March 24, 2023, 10:52am UTC](https://discourse.julialang.org/t/data-property-editor-not-working-in-geniebuilder/96551 "2023-03-24T10:52:32Z")

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Hi all, I am going through a tutorial for Genie (which looks really nice by the way), but unfortunately some features are not working. I am trying to edit the min and max fields for the slider, but the value disappears …

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## [Domain error with QuadGK to derive Caputo derivative](https://discourse.julialang.org/t/domain-error-with-quadgk-to-derive-caputo-derivative/96550)

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**Author:** [@khaledharizb](https://discourse.julialang.org/u/khaledharizb)\
**Replies:** 2\
**Last updated:** [March 24, 2023, 3:57pm UTC](https://discourse.julialang.org/t/domain-error-with-quadgk-to-derive-caputo-derivative/96550 "2023-03-24T15:57:06Z")

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Hi everyone! I’m trying to evaluate caputo derivative using Quadgk. It works unless when t=3 it gives me Domain error. With Mathematica I got the value -3.11522 using QuadGK, ForwardDiff, SpecialFunctions f(t)=t^2\*sin(t…

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## [Producing Fold Bifurcation Diagram using BirfurcationKit](https://discourse.julialang.org/t/producing-fold-bifurcation-diagram-using-birfurcationkit/96543)

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**Author:** [@Tristan](https://discourse.julialang.org/u/Tristan)\
**Replies:** 4\
**Last updated:** [March 24, 2023, 3:16pm UTC](https://discourse.julialang.org/t/producing-fold-bifurcation-diagram-using-birfurcationkit/96543 "2023-03-24T15:16:33Z")

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I am trying to construct a bifurcation diagram in Julia using Bifurcation.Kit package. I cannot get the graph I am expect to produce. For some context, I am modeling a system of ODEs (non linear, 6 equations, and 6 unkno…

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## [Why making tuples from excels columns take so much times?](https://discourse.julialang.org/t/why-making-tuples-from-excels-columns-take-so-much-times/96560)

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**Author:** [@Optimization](https://discourse.julialang.org/u/Optimization)\
**Replies:** 5\
**Last updated:** [March 24, 2023, 2:42pm UTC](https://discourse.julialang.org/t/why-making-tuples-from-excels-columns-take-so-much-times/96560 "2023-03-24T14:42:09Z")

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I have an excel sheet that has four colums of length 10000, and I’d like to create list of tuples from two colums. So, I used list comprehension first, and after 10 minutes is was still running. So, I did this: twos = V…

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## [Is it possible to implement own \`.\<tab\>\` autocomplete for \`getindex\` in REPL (without AbstractDict)](https://discourse.julialang.org/t/is-it-possible-to-implement-own-tab-autocomplete-for-getindex-in-repl-without-abstractdict/96552)

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**Author:** [@SteffenPL](https://discourse.julialang.org/u/SteffenPL)\
**Replies:** 3\
**Last updated:** [March 24, 2023, 11:59am UTC](https://discourse.julialang.org/t/is-it-possible-to-implement-own-tab-autocomplete-for-getindex-in-repl-without-abstractdict/96552 "2023-03-24T11:59:40Z")

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I have some datatype, for which I would like to have autocomplete for getindex/setindex!, e.g. myData\[.\<tab\> should give me all the keys(myData). So far, I get that I can subtype AbstractDict{Symbol,Any} to archive that…

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## [Macro to choose macros](https://discourse.julialang.org/t/macro-to-choose-macros/96507)

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**Author:** [@weymouth](https://discourse.julialang.org/u/weymouth)\
**Replies:** 6\
**Last updated:** [March 24, 2023, 8:35am UTC](https://discourse.julialang.org/t/macro-to-choose-macros/96507 "2023-03-24T08:35:19Z")

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It seems I still don’t understand how macros really work in Julia. (sigh) I want to define a macro @always\_fast which will insert @simd or Threads.@threads depending on the value of Threads.nthreads() for cases like: @…

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## [Is Julia well-suited for string manipulation?](https://discourse.julialang.org/t/is-julia-well-suited-for-string-manipulation/92943)

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**Author:** [@jules](https://discourse.julialang.org/u/jules)\
**Replies:** 24\
**Last updated:** [March 24, 2023, 4:26am UTC](https://discourse.julialang.org/t/is-julia-well-suited-for-string-manipulation/92943 "2023-03-24T04:26:51Z")

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Why do I sometimes read that Julia is not particularly well suited for string manipulation? I read about Perl or Python being good at that but I’ve never seen a technical explanation what puts Julia at a disadvantage per…

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## [Is DifferentialEquations 7.7.0 slowing the REPL in Julia 1.8.5?](https://discourse.julialang.org/t/is-differentialequations-7-7-0-slowing-the-repl-in-julia-1-8-5/96482)

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**Author:** [@RayleighLord](https://discourse.julialang.org/u/RayleighLord)\
**Replies:** 2\
**Last updated:** [March 24, 2023, 1:41am UTC](https://discourse.julialang.org/t/is-differentialequations-7-7-0-slowing-the-repl-in-julia-1-8-5/96482 "2023-03-24T01:41:03Z")

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I recently updated to this version of the DifferentialEquations package and observed that my code execution became considerably slower after loading the package. To ensure that this issue was isolated to the package itse…

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## [Efficiently in-place filling an array of ForwardDiff.Dual](https://discourse.julialang.org/t/efficiently-in-place-filling-an-array-of-forwarddiff-dual/96537)

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**Author:** [@cadaverous](https://discourse.julialang.org/u/cadaverous)\
**Replies:** 2\
**Last updated:** [March 24, 2023, 12:35am UTC](https://discourse.julialang.org/t/efficiently-in-place-filling-an-array-of-forwarddiff-dual/96537 "2023-03-24T00:35:29Z")

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I was able to write function to handle arrays of ForwardDiff.Dual, since in theory I should be able to compute the derivative of a certain function much more efficiently than just propagating Dual numbers through it. I h…

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## [It Is fine to split your package into multiple sub-packages? And when should i do that?](https://discourse.julialang.org/t/it-is-fine-to-split-your-package-into-multiple-sub-packages-and-when-should-i-do-that/88776)

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**Author:** [@dylanxyz](https://discourse.julialang.org/u/dylanxyz)\
**Replies:** 3\
**Last updated:** [March 24, 2023, 12:08am UTC](https://discourse.julialang.org/t/it-is-fine-to-split-your-package-into-multiple-sub-packages-and-when-should-i-do-that/88776 "2023-03-24T00:08:10Z")

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When i was writing Kotlin or Typescript, my way of organizing a project was to divide it into sub folders where each sub folder defines its own module, and the job of the main module was just to re-exports the sub-module…

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## [Check if a sorting algorithm is stable](https://discourse.julialang.org/t/check-if-a-sorting-algorithm-is-stable/96536)

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**Author:** [@jar1](https://discourse.julialang.org/u/jar1)\
**Replies:** 1\
**Last updated:** [March 23, 2023, 9:33pm UTC](https://discourse.julialang.org/t/check-if-a-sorting-algorithm-is-stable/96536 "2023-03-23T21:33:26Z")

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Say I want to know if the default float sorting algorithm is stable. How can I check? julia\> Base.Sort.defalg(rand(3)) Base.Sort.MissingOptimization( Base.Sort.BoolOptimization( Base.Sort.Small{10}( …

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## [How to extract solution values "x" if solution is obtained using ReachabilityAnalysis.jl package?](https://discourse.julialang.org/t/how-to-extract-solution-values-x-if-solution-is-obtained-using-reachabilityanalysis-jl-package/96532)

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**Author:** [@Ashu](https://discourse.julialang.org/u/Ashu)\
**Replies:** 0\
**Last updated:** [March 23, 2023, 8:05pm UTC](https://discourse.julialang.org/t/how-to-extract-solution-values-x-if-solution-is-obtained-using-reachabilityanalysis-jl-package/96532 "2023-03-23T20:05:15Z")

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Hello all, I am solving a differential equation with an initial condition in an interval using ReachabilityAnalysis.jl package as, prob = @ivp(x' = f(x), x(0) ∈ X0, dim=1) sol = solve(prob, alg=TMJets21a(abstol=1e-18),…

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## [StipplePlotly.PlotLayout using Mapbox token](https://discourse.julialang.org/t/stippleplotly-plotlayout-using-mapbox-token/96524)

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**Author:** [@monty](https://discourse.julialang.org/u/monty)\
**Replies:** 0\
**Last updated:** [March 23, 2023, 5:54pm UTC](https://discourse.julialang.org/t/stippleplotly-plotlayout-using-mapbox-token/96524 "2023-03-23T17:54:23Z")

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How I can specify the Mapbox token when I am using StipplePlotly.PlotLayout?

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## [StipplePlotly.PlotLayout using USGS layer](https://discourse.julialang.org/t/stippleplotly-plotlayout-using-usgs-layer/96523)

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**Author:** [@monty](https://discourse.julialang.org/u/monty)\
**Replies:** 0\
**Last updated:** [March 23, 2023, 5:37pm UTC](https://discourse.julialang.org/t/stippleplotly-plotlayout-using-usgs-layer/96523 "2023-03-23T17:37:04Z")

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How to use USGS layer in StipplePlotly.PlotLayout? according to Plotly.js website you can load USGS terrain in Plotly: import pandas as pd us\_cities = pd.read\_csv("https://raw.githubusercontent.com/plotly/datasets/mast…

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## [What is cause of "Unable to automatically install" \_jll errors?](https://discourse.julialang.org/t/what-is-cause-of-unable-to-automatically-install-jll-errors/38992)

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**Author:** [@djsegal](https://discourse.julialang.org/u/djsegal)\
**Replies:** 6\
**Last updated:** [March 23, 2023, 4:37pm UTC](https://discourse.julialang.org/t/what-is-cause-of-unable-to-automatically-install-jll-errors/38992 "2023-03-23T16:37:48Z")

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I’m getting a lot of ERROR: Unable to automatically install messages from add PkgTemplates // think it’s from Artifacts.toml or some \_jll binary downloader, but have no real clue whats going on Can anyone say what’s ha…

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## [How to save plotly to png and is it possible to save to LaTex?](https://discourse.julialang.org/t/how-to-save-plotly-to-png-and-is-it-possible-to-save-to-latex/33509)

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**Author:** [@BMval](https://discourse.julialang.org/u/BMval)\
**Replies:** 6\
**Last updated:** [March 23, 2023, 3:03pm UTC](https://discourse.julialang.org/t/how-to-save-plotly-to-png-and-is-it-possible-to-save-to-latex/33509 "2023-03-23T15:03:20Z")

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How to save plotly to png and is it possible to save to LaTe? Thank you.

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## [Cannot install package because of bad certificate](https://discourse.julialang.org/t/cannot-install-package-because-of-bad-certificate/96432)

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**Author:** [@Yannik](https://discourse.julialang.org/u/Yannik)\
**Replies:** 1\
**Last updated:** [March 23, 2023, 1:52pm UTC](https://discourse.julialang.org/t/cannot-install-package-because-of-bad-certificate/96432 "2023-03-23T13:52:29Z")

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When trying to install certain packages (for example: MixedModels or TuringGLM) I get an error about download/install artifact tzdata2022f. The “problematic” package seems to be TimeZones.jl. The same problem occurs if I…

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## [Weird floating point vs rational behavior](https://discourse.julialang.org/t/weird-floating-point-vs-rational-behavior/96466)

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**Author:** [@DOT](https://discourse.julialang.org/u/DOT)\
**Replies:** 6\
**Last updated:** [March 23, 2023, 12:28pm UTC](https://discourse.julialang.org/t/weird-floating-point-vs-rational-behavior/96466 "2023-03-23T12:28:54Z")

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Just when you think you’ve seen it all: Could someone please explain this to me? julia\> 10\*1.1 ≤ 11 true julia\> (10//1)\*1.1 ≤ (11//1) true julia\> (10//1)\*1.1 - (11//1) ≤ 0 true julia\> 1 ≤ (11//10)/1.1 true julia\> 1.…

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## [Isdir in Windows 67 times slower than Linux](https://discourse.julialang.org/t/isdir-in-windows-67-times-slower-than-linux/96436)

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**Author:** [@Jeremy](https://discourse.julialang.org/u/Jeremy)\
**Replies:** 16\
**Last updated:** [March 23, 2023, 12:31pm UTC](https://discourse.julialang.org/t/isdir-in-windows-67-times-slower-than-linux/96436 "2023-03-23T12:31:09Z")

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I need to list a large number of files and parse their names. My function works but the performance in Windows is 67 times slower despite running on a more powerful computer. The number of files is unknown and the user c…

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## [Code jumping in julia vscode most often does not work - what is it I am doing wrong?](https://discourse.julialang.org/t/code-jumping-in-julia-vscode-most-often-does-not-work-what-is-it-i-am-doing-wrong/96376)

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**Author:** [@schlichtanders](https://discourse.julialang.org/u/schlichtanders)\
**Replies:** 10\
**Last updated:** [March 22, 2023, 3:10pm UTC](https://discourse.julialang.org/t/code-jumping-in-julia-vscode-most-often-does-not-work-what-is-it-i-am-doing-wrong/96376 "2023-03-22T15:10:04Z")

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Hi there, I would like to gather some experiences about how good vscode completion is working for you. Almost all the time I have problems jumping to source code in some nested subpackges, etc… If I do a Julia: Re-inde…

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## [Issues with MethodOfLines in SciML tutorial](https://discourse.julialang.org/t/issues-with-methodoflines-in-sciml-tutorial/96398)

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**Author:** [@Naceur\_Bouziani](https://discourse.julialang.org/u/Naceur_Bouziani)\
**Replies:** 20\
**Last updated:** [March 23, 2023, 11:47am UTC](https://discourse.julialang.org/t/issues-with-methodoflines-in-sciml-tutorial/96398 "2023-03-23T11:47:50Z")

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Hello everyone. I used to use MethodeOfLines to learn and start using all the great work of Chris and all this wonderful community But after running an update in the last 3 days I can’t even run the example tutorial t…

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## [Video Processing](https://discourse.julialang.org/t/video-processing/96490)

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**Author:** [@Desmond](https://discourse.julialang.org/u/Desmond)\
**Replies:** 7\
**Last updated:** [March 23, 2023, 11:45am UTC](https://discourse.julialang.org/t/video-processing/96490 "2023-03-23T11:45:37Z")

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So, I took a video and svd decomposition on all the frames and I have got all my frames together. I am to look for a package that can help me put the frames together back in a video. But i can seem to find any. VideoIO,…

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## [Bug in algebra in REPL?](https://discourse.julialang.org/t/bug-in-algebra-in-repl/96500)

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**Author:** [@Ron\_Backal](https://discourse.julialang.org/u/Ron_Backal)\
**Replies:** 1\
**Last updated:** [March 23, 2023, 11:16am UTC](https://discourse.julialang.org/t/bug-in-algebra-in-repl/96500 "2023-03-23T11:16:18Z")

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I got a very absurd result when I used the REPL today for linear algebra calculations. I entered first the Windows Terminal(new version) and then typed Julia and entered the REPL. I calculated some 2 dimensional vector,…

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## [ReverseDiff with Flux model](https://discourse.julialang.org/t/reversediff-with-flux-model/96452)

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**Author:** [@Avec](https://discourse.julialang.org/u/Avec)\
**Replies:** 2\
**Last updated:** [March 23, 2023, 10:04am UTC](https://discourse.julialang.org/t/reversediff-with-flux-model/96452 "2023-03-23T10:04:28Z")

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Hi all, I am trying to get a gradient of a Flux model with a different package than Zygote or ForwardDiff (Zygote cannot get through my real loss function and ForwardDiff is too slow). Since my loss function returns scal…

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## [A problem about multi-threading and IO](https://discourse.julialang.org/t/a-problem-about-multi-threading-and-io/96492)

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**Author:** [@fenyutanchan](https://discourse.julialang.org/u/fenyutanchan)\
**Replies:** 0\
**Last updated:** [March 23, 2023, 5:59am UTC](https://discourse.julialang.org/t/a-problem-about-multi-threading-and-io/96492 "2023-03-23T05:59:10Z")

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I’m trying write a code as make\_random\_string(n::Int)::String = (prod ∘ map)(Char, rand(65:90, n)) function outer\_string(n::Int)::Tuple{String, String} orig\_str = make\_random\_string(n) result\_io = I…

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## [Replace elements of matrix when executing condition](https://discourse.julialang.org/t/replace-elements-of-matrix-when-executing-condition/96465)

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**Author:** [@Sergey\_Novak](https://discourse.julialang.org/u/Sergey_Novak)\
**Replies:** 2\
**Last updated:** [March 23, 2023, 6:21am UTC](https://discourse.julialang.org/t/replace-elements-of-matrix-when-executing-condition/96465 "2023-03-23T06:21:48Z")

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Hello. I have next matrix: 200×200 Matrix{Float64}: -3.14652 -3.09094 -3.03716 -2.98602 … -0.311487 -0.311531 -3.12573 -3.07036 -3.01627 -2.96592 -0.311478 -0.311522 -3.10504 -3.05 …

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## [Performance tips for a function which finds n maximums in a matrix](https://discourse.julialang.org/t/performance-tips-for-a-function-which-finds-n-maximums-in-a-matrix/96425)

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**Author:** [@eduardosalaz](https://discourse.julialang.org/u/eduardosalaz)\
**Replies:** 8\
**Last updated:** [March 23, 2023, 5:49am UTC](https://discourse.julialang.org/t/performance-tips-for-a-function-which-finds-n-maximums-in-a-matrix/96425 "2023-03-23T05:49:13Z")

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Hi everyone, I have been trying to squeeze out as much performance as possible out from the following function, which finds the n largest (or maximum) values of a matrix and returns those values and their positions in t…

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## [Wrap and inherit Number](https://discourse.julialang.org/t/wrap-and-inherit-number/4799)

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**Author:** [@yakir12](https://discourse.julialang.org/u/yakir12)\
**Replies:** 26\
**Last updated:** [March 23, 2023, 5:14am UTC](https://discourse.julialang.org/t/wrap-and-inherit-number/4799 "2023-03-23T05:14:32Z")

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I’ve seen topics touching this in different constellations, but: How do people create a new type that would magically behave just like any subtype of (say) Number? So for example, if: struct A{T \<: Number} x::T end…

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