# Latest

**URL:** https://discourse.julialang.org/latest.md?page=1076

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

**Page:** 1077

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## [Comparison 2 data sets](https://discourse.julialang.org/t/comparison-2-data-sets/78790)

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**Author:** [@ab2z](https://discourse.julialang.org/u/ab2z)\
**Replies:** 6\
**Last updated:** [April 5, 2022, 8:38am UTC](https://discourse.julialang.org/t/comparison-2-data-sets/78790 "2022-04-05T08:38:20Z")

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Hi all, I am new in Julia so I would like to start with a simple question. In testing the migration activities from old to a new system/setting/etc, we mostly need to compare 2 output data sets and extract the deltas. …

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## [Custom pretty printing post-processing](https://discourse.julialang.org/t/custom-pretty-printing-post-processing/78844)

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**Author:** [@jedforrest](https://discourse.julialang.org/u/jedforrest)\
**Replies:** 3\
**Last updated:** [April 5, 2022, 8:06am UTC](https://discourse.julialang.org/t/custom-pretty-printing-post-processing/78844 "2022-04-05T08:06:01Z")

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I want to modify a custom pretty printing function for a type defined by another package. However, I don’t want to override their printing function, I just want to post-process the string before it is printed. In partic…

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## [Parallel HDF5 settings](https://discourse.julialang.org/t/parallel-hdf5-settings/79028)

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**Author:** [@sjhong6230](https://discourse.julialang.org/u/sjhong6230)\
**Replies:** 2\
**Last updated:** [April 5, 2022, 6:55am UTC](https://discourse.julialang.org/t/parallel-hdf5-settings/79028 "2022-04-05T06:55:59Z")

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https://juliaio.github.io/HDF5.jl/stable/#Using-custom-or-system-provided-HDF5-binaries I am trying to use parallel HDF5 for my MPI I/O jobs. However, the test from the “https://github.com/JuliaIO/HDF5.jl/blob/master/te…

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## [Hyperparameters optimization packages for ML application in Julia](https://discourse.julialang.org/t/hyperparameters-optimization-packages-for-ml-application-in-julia/33519)

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**Author:** [@Simon\_Besnard](https://discourse.julialang.org/u/Simon_Besnard)\
**Replies:** 7\
**Last updated:** [April 5, 2022, 6:37am UTC](https://discourse.julialang.org/t/hyperparameters-optimization-packages-for-ml-application-in-julia/33519 "2022-04-05T06:37:20Z")

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Hi all, I am currently working with Flux.jl package for deep learning model implementation. I was wondering if some of you have had experience with some hyperparameters optimization packages (e.g. using hyperbands optim…

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## [Can Julia always return the path to a directory with \`/\` at the end?](https://discourse.julialang.org/t/can-julia-always-return-the-path-to-a-directory-with-at-the-end/78974)

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**Author:** [@singularitti](https://discourse.julialang.org/u/singularitti)\
**Replies:** 13\
**Last updated:** [April 5, 2022, 6:14am UTC](https://discourse.julialang.org/t/can-julia-always-return-the-path-to-a-directory-with-at-the-end/78974 "2022-04-05T06:14:45Z")

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In Julia, sometimes a path to a directory is returned with / at the end, but sometimes not. For example, julia\> homedir() "/users/xxxxx" julia\> joinpath(homedir(), "documents/") "/users/xxxxx/documents/" Here /users/x…

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## [Successfully added the packages but can not use the packages](https://discourse.julialang.org/t/successfully-added-the-packages-but-can-not-use-the-packages/79032)

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**Author:** [@yujie\_zhao](https://discourse.julialang.org/u/yujie_zhao)\
**Replies:** 2\
**Last updated:** [April 5, 2022, 6:08am UTC](https://discourse.julialang.org/t/successfully-added-the-packages-but-can-not-use-the-packages/79032 "2022-04-05T06:08:41Z")

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Hi all ! my question is like the following. I added the packages but can not use it. thank you!

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## [@spawn at fails when called inside a function in a module](https://discourse.julialang.org/t/spawn-at-fails-when-called-inside-a-function-in-a-module/79001)

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**Author:** [@Sijun](https://discourse.julialang.org/u/Sijun)\
**Replies:** 4\
**Last updated:** [April 5, 2022, 12:10am UTC](https://discourse.julialang.org/t/spawn-at-fails-when-called-inside-a-function-in-a-module/79001 "2022-04-05T00:10:39Z")

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I have @spawnat expression run inside a function in a module and get the following error: module Test using Distributed function test() t = @spawnat :2 1==1 @show fetch(t) end end julia\> Test.test() ERROR: On…

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## [Numpy Diff in Julia DataFrames?](https://discourse.julialang.org/t/numpy-diff-in-julia-dataframes/79019)

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**Author:** [@anon69491625](https://discourse.julialang.org/u/anon69491625)\
**Replies:** 3\
**Last updated:** [April 4, 2022, 9:26pm UTC](https://discourse.julialang.org/t/numpy-diff-in-julia-dataframes/79019 "2022-04-04T21:26:03Z")

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can’t find the rolling diff in julia. Don’t want to use pycall just for this one thing. close\_data = \[147.82,149.5,149.78,149.86,149.93,150.89,152.39,153.74,152.79,151.23,151.78\] In pandas/numpy I can just run r = di…

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## [Multiple dispatch unexpected function call](https://discourse.julialang.org/t/multiple-dispatch-unexpected-function-call/78736)

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**Author:** [@Wikunia](https://discourse.julialang.org/u/Wikunia)\
**Replies:** 21\
**Last updated:** [April 4, 2022, 9:21pm UTC](https://discourse.julialang.org/t/multiple-dispatch-unexpected-function-call/78736 "2022-04-04T21:21:42Z")

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I just encountered weird behavior with multiple dispatch which I didn’t expect. julia\> abstract type AbstractType end julia\> struct ExampleType\<:AbstractType end julia\> struct Concrete{AT\<:AbstractType} end julia\> is…

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## [Is it possible to use different programming languages within a single Pluto.jl notebook?](https://discourse.julialang.org/t/is-it-possible-to-use-different-programming-languages-within-a-single-pluto-jl-notebook/79008)

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**Author:** [@Hashir\_Omer](https://discourse.julialang.org/u/Hashir_Omer)\
**Replies:** 3\
**Last updated:** [April 4, 2022, 7:34pm UTC](https://discourse.julialang.org/t/is-it-possible-to-use-different-programming-languages-within-a-single-pluto-jl-notebook/79008 "2022-04-04T19:34:54Z")

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I recently discovered Pluto and I prefer working with it over Jupyter notebooks if I am only using julia. However, sometimes I have to use Python as well for some of the packages. The SOS polyglot notebook is an extensi…

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## [Method Error object of type AgentBasedModel is not callable](https://discourse.julialang.org/t/method-error-object-of-type-agentbasedmodel-is-not-callable/79014)

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**Author:** [@imantha](https://discourse.julialang.org/u/imantha)\
**Replies:** 2\
**Last updated:** [April 4, 2022, 7:32pm UTC](https://discourse.julialang.org/t/method-error-object-of-type-agentbasedmodel-is-not-callable/79014 "2022-04-04T19:32:07Z")

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Hi I am having the following error when I call the step!() or abmvideo!() functions and not sure what the cause of it is. Any ideas? ERROR: MethodError: objects of type AgentBasedModel{Agents.OSM.OpenStreetMapSpace, Uni…

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## [Shared environments?](https://discourse.julialang.org/t/shared-environments/79002)

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**Author:** [@lmiq](https://discourse.julialang.org/u/lmiq)\
**Replies:** 35\
**Last updated:** [April 4, 2022, 7:25pm UTC](https://discourse.julialang.org/t/shared-environments/79002 "2022-04-04T19:25:39Z")

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I just happen to find out about the existence of the shared environments. However, I could not find what are they useful for, and the doc string does not tell me much. What are they useful for? In what they differ from o…

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## [SubString and missing](https://discourse.julialang.org/t/substring-and-missing/79017)

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**Author:** [@gjh](https://discourse.julialang.org/u/gjh)\
**Replies:** 3\
**Last updated:** [April 4, 2022, 7:25pm UTC](https://discourse.julialang.org/t/substring-and-missing/79017 "2022-04-04T19:25:03Z")

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with this vector str = \[“az”, “by”, missing, “cx”\] how can I get this returned using SubString? \[“a”, “b”, missing, “c”\] Thank you!

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## [JuliaCon 2022: Call for proposal extension and call for reviewers](https://discourse.julialang.org/t/juliacon-2022-call-for-proposal-extension-and-call-for-reviewers/78644)

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**Author:** [@vchuravy](https://discourse.julialang.org/u/vchuravy)\
**Replies:** 1\
**Last updated:** [April 4, 2022, 5:46pm UTC](https://discourse.julialang.org/t/juliacon-2022-call-for-proposal-extension-and-call-for-reviewers/78644 "2022-04-04T17:46:03Z")

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Hello folks! The JuliaCon CfP is closing soon! We decided today to extend the call for another week so the new closing data is April 11th, For more information see the original annoucements Two more annoucements! If …

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## [Broken links in VSCode DocStrings e.g. 'PLACEHOLDER/core.js'](https://discourse.julialang.org/t/broken-links-in-vscode-docstrings-e-g-placeholder-core-js/78940)

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**Author:** [@lukesdm](https://discourse.julialang.org/u/lukesdm)\
**Replies:** 3\
**Last updated:** [April 4, 2022, 5:07pm UTC](https://discourse.julialang.org/t/broken-links-in-vscode-docstrings-e-g-placeholder-core-js/78940 "2022-04-04T17:07:30Z")

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Hi, I’m seeing that in VS Code, ‘go to definition’ seems to be working inconsistently, and in the docstrings, instead of the package, it is showing e.g. ‘PLACEHOLDER/core.js’. Any ideas on what’s causing this or how t…

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## [Adaptive SDESolver yields "Warning: dt \<= dtmin. Aborting", unsure why, large non-adaptive dt works fine](https://discourse.julialang.org/t/adaptive-sdesolver-yields-warning-dt-dtmin-aborting-unsure-why-large-non-adaptive-dt-works-fine/78859)

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**Author:** [@Torkel](https://discourse.julialang.org/u/Torkel)\
**Replies:** 5\
**Last updated:** [April 4, 2022, 4:20pm UTC](https://discourse.julialang.org/t/adaptive-sdesolver-yields-warning-dt-dtmin-aborting-unsure-why-large-non-adaptive-dt-works-fine/78859 "2022-04-04T16:20:26Z")

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I have a simple model, which I am trying to simulate, however, I am getting ┌ Warning: dt \<= dtmin. Aborting. There is either an error in your model specification or the true solution is unstable. └ @ SciMLBase /home/SL…

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## [How to calculate derivative by Lagrange interpolation](https://discourse.julialang.org/t/how-to-calculate-derivative-by-lagrange-interpolation/74905)

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**Author:** [@manoj.centura](https://discourse.julialang.org/u/manoj.centura)\
**Replies:** 5\
**Last updated:** [April 4, 2022, 4:11pm UTC](https://discourse.julialang.org/t/how-to-calculate-derivative-by-lagrange-interpolation/74905 "2022-04-04T16:11:42Z")

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hi All, is there a pkg to calculate derivative at untabulated points using langrange interpolation? Thanks M

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## [\[ANN\] Kelpie.jl: An HTML templating engine in pure Julia](https://discourse.julialang.org/t/ann-kelpie-jl-an-html-templating-engine-in-pure-julia/79004)

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**Author:** [@MillironX](https://discourse.julialang.org/u/MillironX)\
**Replies:** 5\
**Last updated:** [April 4, 2022, 4:05pm UTC](https://discourse.julialang.org/t/ann-kelpie-jl-an-html-templating-engine-in-pure-julia/79004 "2022-04-04T16:05:17Z")

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Kelpie wraps EzXML.jl nodes with functions taken from the names of HTML5 elements (e.g. a, img, nav, etc.). Each function takes the content of the element as a positional argument, and translates all keyword arguments …

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## [\[ANN\] ForwardDiffPullbacks.jl, ForwardDiff-based ChainRulesCore pullbacks](https://discourse.julialang.org/t/ann-forwarddiffpullbacks-jl-forwarddiff-based-chainrulescore-pullbacks/78737)

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**Author:** [@oschulz](https://discourse.julialang.org/u/oschulz)\
**Replies:** 14\
**Last updated:** [April 4, 2022, 3:59pm UTC](https://discourse.julialang.org/t/ann-forwarddiffpullbacks-jl-forwarddiff-based-chainrulescore-pullbacks/78737 "2022-04-04T15:59:29Z")

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I’m happy to announce ForwardDiffPullbacks.jl. It’s been around for a bit, but hasn’t been quite ready to annouce until now (v0.2.1 that is). ForwardDiffPullbacks implements pullbacks compatible with ChainRulesCore that…

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## [How Documenter makes docs for different versions?](https://discourse.julialang.org/t/how-documenter-makes-docs-for-different-versions/22445)

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**Author:** [@cserteGT3](https://discourse.julialang.org/u/cserteGT3)\
**Replies:** 13\
**Last updated:** [April 4, 2022, 3:36pm UTC](https://discourse.julialang.org/t/how-documenter-makes-docs-for-different-versions/22445 "2022-04-04T15:36:33Z")

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I’m working on a small project (not julia related), that needs documentation. I really like the sites that Documenter.jl builds, particularly that I can see the docs of different versions (and the master branch). I would…

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## [How to generate two sets from distinct points on a sphere, and plot them?](https://discourse.julialang.org/t/how-to-generate-two-sets-from-distinct-points-on-a-sphere-and-plot-them/79010)

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**Author:** [@OliveiraIgor](https://discourse.julialang.org/u/OliveiraIgor)\
**Replies:** 0\
**Last updated:** [April 4, 2022, 3:36pm UTC](https://discourse.julialang.org/t/how-to-generate-two-sets-from-distinct-points-on-a-sphere-and-plot-them/79010 "2022-04-04T15:36:21Z")

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I need to apply the PCA at different points of a spherical cap, but I don’t know how to build these sets of different points, I need at least 2 sets. Here is a picture with the idea of what I need.

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## [Plot of OSM.test\_map() offered in agents.jl seem incorrect](https://discourse.julialang.org/t/plot-of-osm-test-map-offered-in-agents-jl-seem-incorrect/78948)

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**Author:** [@imantha](https://discourse.julialang.org/u/imantha)\
**Replies:** 4\
**Last updated:** [April 4, 2022, 3:35pm UTC](https://discourse.julialang.org/t/plot-of-osm-test-map-offered-in-agents-jl-seem-incorrect/78948 "2022-04-04T15:35:02Z")

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Hi, I recently updated agents.jl → 5.0.0 and InteractiveDynamics.jl → 0.20.1. I am trying to use abmvideo() and ambplot() functions to plot an openstreet test map offered by the package. However something seems to be in…

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## [How is the behaviour of using changed in the REPL?](https://discourse.julialang.org/t/how-is-the-behaviour-of-using-changed-in-the-repl/79009)

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**Author:** [@feanor12](https://discourse.julialang.org/u/feanor12)\
**Replies:** 0\
**Last updated:** [April 4, 2022, 3:32pm UTC](https://discourse.julialang.org/t/how-is-the-behaviour-of-using-changed-in-the-repl/79009 "2022-04-04T15:32:44Z")

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In the REPL using can trigger Pkg.add. Is it possible to use this also in non-REPL sessions?

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## [Error message in adding a package](https://discourse.julialang.org/t/error-message-in-adding-a-package/78992)

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**Author:** [@habeebadeyemi](https://discourse.julialang.org/u/habeebadeyemi)\
**Replies:** 5\
**Last updated:** [April 4, 2022, 3:31pm UTC](https://discourse.julialang.org/t/error-message-in-adding-a-package/78992 "2022-04-04T15:31:17Z")

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trying to add pluto package and below is error message i get. Error: The following package names could not be resolved:

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## [Collaborative development workflow for multiple packages simultaneously on multiple machines](https://discourse.julialang.org/t/collaborative-development-workflow-for-multiple-packages-simultaneously-on-multiple-machines/78942)

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**Author:** [@claudio20497](https://discourse.julialang.org/u/claudio20497)\
**Replies:** 1\
**Last updated:** [April 4, 2022, 2:57pm UTC](https://discourse.julialang.org/t/collaborative-development-workflow-for-multiple-packages-simultaneously-on-multiple-machines/78942 "2022-04-04T14:57:28Z")

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Hello, I’m simultaneously developing two packages, say mypkgA.jl and mypkgB.jl, where mypkgA.jl depends on mypkgB.jl. They’re both currently unregistered, and I have to work on two different machines depending on the da…

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## [Eigenvalues are approximately correct, not exactly](https://discourse.julialang.org/t/eigenvalues-are-approximately-correct-not-exactly/78952)

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**Author:** [@Vahid\_Hosseinzadeh](https://discourse.julialang.org/u/Vahid_Hosseinzadeh)\
**Replies:** 6\
**Last updated:** [April 4, 2022, 2:50pm UTC](https://discourse.julialang.org/t/eigenvalues-are-approximately-correct-not-exactly/78952 "2022-04-04T14:50:21Z")

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Hi everybody, using LinearAlgebra eigvals(\[0. 1im;1im 0.\]) gives: 2-element Vector{ComplexF64}: 0.0 + 0.9999999999999997im 2.7755575615628914e-17 - 1.0im which is correct but with approximation.…

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## [How to use labels instead of numbers in xtick and ytick](https://discourse.julialang.org/t/how-to-use-labels-instead-of-numbers-in-xtick-and-ytick/79006)

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**Author:** [@Christopher\_Fisher](https://discourse.julialang.org/u/Christopher_Fisher)\
**Replies:** 2\
**Last updated:** [April 4, 2022, 1:57pm UTC](https://discourse.julialang.org/t/how-to-use-labels-instead-of-numbers-in-xtick-and-ytick/79006 "2022-04-04T13:57:51Z")

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Hi all, I would like to use labels “low” and “high” on the x and y axis rather than numbers. For example, on the y-axis, “low” would be on the bottom and “high” would be on the top. I could potentially use annotate for…

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## [What are the limitations of completion in the REPL?](https://discourse.julialang.org/t/what-are-the-limitations-of-completion-in-the-repl/78944)

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**Author:** [@PetrKryslUCSD](https://discourse.julialang.org/u/PetrKryslUCSD)\
**Replies:** 11\
**Last updated:** [April 4, 2022, 1:31pm UTC](https://discourse.julialang.org/t/what-are-the-limitations-of-completion-in-the-repl/78944 "2022-04-04T13:31:31Z")

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The manual states “Tab completion can also help completing fields:”, using the example of UUIDs. However, I recently found that some symbols are not completed (Where is sparse ldlt? - #2 by skleinbo). So, does anyone k…

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## [Seed random number generator when using pmap](https://discourse.julialang.org/t/seed-random-number-generator-when-using-pmap/78973)

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**Author:** [@jisutich](https://discourse.julialang.org/u/jisutich)\
**Replies:** 2\
**Last updated:** [April 4, 2022, 1:26pm UTC](https://discourse.julialang.org/t/seed-random-number-generator-when-using-pmap/78973 "2022-04-04T13:26:11Z")

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Hi I am trying to use pmap to increase the speed of my code. And I try to seed the random generator in different processors, so I have a code like using Distributed addprocs(4) @everywhere using LinearAlgebra @everywh…

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## [Pre-filled input for readline()](https://discourse.julialang.org/t/pre-filled-input-for-readline/78969)

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**Author:** [@jarbus](https://discourse.julialang.org/u/jarbus)\
**Replies:** 1\
**Last updated:** [April 4, 2022, 12:59pm UTC](https://discourse.julialang.org/t/pre-filled-input-for-readline/78969 "2022-04-04T12:59:31Z")

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Is there a way to pre-fill the buffer for readline()? Say for instance I want to have the following Enter a name for this run: 20XX-MM-DD | where the date is already filled in and a user’s cursor is at the |, that way …

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