# Latest

**URL:** https://discourse.julialang.org/latest.md?page=795

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

**Page:** 796

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## [How can you insert a julia struct into an array of a type in fortran?](https://discourse.julialang.org/t/how-can-you-insert-a-julia-struct-into-an-array-of-a-type-in-fortran/93775)

<div class="topic-metadata">

**Author:** [@dmmpie](https://discourse.julialang.org/u/dmmpie)\
**Replies:** 5\
**Last updated:** [February 1, 2023, 2:28pm UTC](https://discourse.julialang.org/t/how-can-you-insert-a-julia-struct-into-an-array-of-a-type-in-fortran/93775 "2023-02-01T14:28:30Z")

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I am currently trying to create a unittest for a function I have defined in my shared fortran library. This function receives an integer value and inserts it into a previously allocated and declared array of a specific f…

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## [How to read Panda's DataFrames from json file?](https://discourse.julialang.org/t/how-to-read-pandas-dataframes-from-json-file/93749)

<div class="topic-metadata">

**Author:** [@sERRa](https://discourse.julialang.org/u/sERRa)\
**Replies:** 27\
**Last updated:** [February 1, 2023, 1:42pm UTC](https://discourse.julialang.org/t/how-to-read-pandas-dataframes-from-json-file/93749 "2023-02-01T13:42:45Z")

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I have a huge collection of json files containing a single panda’s dataframe each. I would like to open them in julia but I haven’t found the solution. A caveat is that the dataframes have strings as row indexes. Any he…

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## [Joining two dataframes of different size only when colum values are coincident](https://discourse.julialang.org/t/joining-two-dataframes-of-different-size-only-when-colum-values-are-coincident/93855)

<div class="topic-metadata">

**Author:** [@Itzi](https://discourse.julialang.org/u/Itzi)\
**Replies:** 2\
**Last updated:** [February 1, 2023, 1:18pm UTC](https://discourse.julialang.org/t/joining-two-dataframes-of-different-size-only-when-colum-values-are-coincident/93855 "2023-02-01T13:18:34Z")

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Hi! I would like to know what is the best method to join two DataFrames of different size but making one of the variables coincident. Here is an example: using DataFrames df11 = DataFrame(time = 0:5:30, num = 1, valu…

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## [Julia Copenhagen Meetup February 8th, 2023, at the Mærsk Tower](https://discourse.julialang.org/t/julia-copenhagen-meetup-february-8th-2023-at-the-maersk-tower/91817)

<div class="topic-metadata">

**Author:** [@wc4wc4wc4](https://discourse.julialang.org/u/wc4wc4wc4)\
**Replies:** 1\
**Last updated:** [February 1, 2023, 1:14pm UTC](https://discourse.julialang.org/t/julia-copenhagen-meetup-february-8th-2023-at-the-maersk-tower/91817 "2023-02-01T13:14:49Z")

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The next Julia Copenhagen meetup is February 8th, 2023. And this time with one of the best views in Copenhagen! See more at: Julia Copenhagen Meetup – February 8th, Wed, Feb 8, 2023, 6:00 PM | Meetup

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## [Failed to precompile Plots.jl](https://discourse.julialang.org/t/failed-to-precompile-plots-jl/89802)

<div class="topic-metadata">

**Author:** [@Frauke](https://discourse.julialang.org/u/Frauke)\
**Replies:** 4\
**Last updated:** [February 1, 2023, 12:09pm UTC](https://discourse.julialang.org/t/failed-to-precompile-plots-jl/89802 "2023-02-01T12:09:30Z")

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Hi, I’m new to Julia and having troubles with the compilation of Plots.jl. I was able to add the package but it does not precompile as “libx265.dll” seems to be missing. I am far from beeing a computer expert, so I woul…

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## [Set-like operations on DataFrames?](https://discourse.julialang.org/t/set-like-operations-on-dataframes/32004)

<div class="topic-metadata">

**Author:** [@innerlee](https://discourse.julialang.org/u/innerlee)\
**Replies:** 13\
**Last updated:** [February 1, 2023, 12:08pm UTC](https://discourse.julialang.org/t/set-like-operations-on-dataframes/32004 "2023-02-01T12:08:32Z")

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How to merge two dataframes with the same columns, similar to set operations? For example, whether there are functions like df = union(df1, df2, on=:ID) df = intersect(df1, df2, on=:ID) df = diff(df1, df2, on=:ID)

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## [Use of Julia on EEG and fMRI data](https://discourse.julialang.org/t/use-of-julia-on-eeg-and-fmri-data/93603)

<div class="topic-metadata">

**Author:** [@Lester\_Ingber](https://discourse.julialang.org/u/Lester_Ingber)\
**Replies:** 8\
**Last updated:** [February 1, 2023, 11:07am UTC](https://discourse.julialang.org/t/use-of-julia-on-eeg-and-fmri-data/93603 "2023-02-01T11:07:58Z")

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I’d like to use Julia on EEG and fMRI data. I have downloaded on the Ookami supercomputer, i.e., julia-1.8.5-musl-x86\_64.tar.gz . However, trying to run the binary bin/julia gives me ./julia: Exec format error. Binary…

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## [Automatic differentiation of function with special points](https://discourse.julialang.org/t/automatic-differentiation-of-function-with-special-points/93780)

<div class="topic-metadata">

**Author:** [@rpgowers](https://discourse.julialang.org/u/rpgowers)\
**Replies:** 4\
**Last updated:** [February 1, 2023, 9:50am UTC](https://discourse.julialang.org/t/automatic-differentiation-of-function-with-special-points/93780 "2023-02-01T09:50:06Z")

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I am using ForwardDiff.jl to compute derivatives of functions which often contain functions of the form: f(x,y) = x/\[exp(x/y)-1\] which one can show using L’Hôpital’s rule has the value f(0,y) = y. One way to construc…

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## [Security mechanisms available in ZMQ interop](https://discourse.julialang.org/t/security-mechanisms-available-in-zmq-interop/93862)

<div class="topic-metadata">

**Author:** [@asampaio](https://discourse.julialang.org/u/asampaio)\
**Replies:** 0\
**Last updated:** [February 1, 2023, 9:48am UTC](https://discourse.julialang.org/t/security-mechanisms-available-in-zmq-interop/93862 "2023-02-01T09:48:48Z")

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Hi, after taking a look at the interop ZMQ (GitHub - JuliaInterop/ZMQ.jl: Julia interface to ZMQ), my understanding is that, at the moment, the interface does not expose the security mechanisms available in 0MQ, in parti…

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## [How to add sleep to "JuliaRL\_BasicDQN\_CartPole"?](https://discourse.julialang.org/t/how-to-add-sleep-to-juliarl-basicdqn-cartpole/93810)

<div class="topic-metadata">

**Author:** [@MikeB](https://discourse.julialang.org/u/MikeB)\
**Replies:** 7\
**Last updated:** [February 1, 2023, 9:08am UTC](https://discourse.julialang.org/t/how-to-add-sleep-to-juliarl-basicdqn-cartpole/93810 "2023-02-01T09:08:17Z")

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I’m trying to use the above-named ReinforcementLearning.jl experiment to model training a DQN that calls out to another program and introduces some lag time. I can, of course, run the experiment but I can’t quite figure …

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## [Changing RL Experiment Arguments](https://discourse.julialang.org/t/changing-rl-experiment-arguments/93856)

<div class="topic-metadata">

**Author:** [@MikeB](https://discourse.julialang.org/u/MikeB)\
**Replies:** 1\
**Last updated:** [February 1, 2023, 9:06am UTC](https://discourse.julialang.org/t/changing-rl-experiment-arguments/93856 "2023-02-01T09:06:52Z")

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This is kind of embarrassing, but, I can’t figure out how to change the seed=123 argument on the DQN\_Cartpole experiment. I threw the code into a Jupyter notebook, with the function in one big cell, then the ex=E'JuliaR…

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## [Why are two functions behave differently?](https://discourse.julialang.org/t/why-are-two-functions-behave-differently/93848)

<div class="topic-metadata">

**Author:** [@hungpham3112](https://discourse.julialang.org/u/hungpham3112)\
**Replies:** 2\
**Last updated:** [February 1, 2023, 5:53am UTC](https://discourse.julialang.org/t/why-are-two-functions-behave-differently/93848 "2023-02-01T05:53:30Z")

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I’m doing some exercises in the ThinkJulia book. Specifically, I try to solve the exercise 10-10: Write a function that reads the file words.txt and builds an array with one element per word. Write two versions of thi…

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## [Help in Optim/optimize - structure of code and help](https://discourse.julialang.org/t/help-in-optim-optimize-structure-of-code-and-help/93656)

<div class="topic-metadata">

**Author:** [@Outeirom](https://discourse.julialang.org/u/Outeirom)\
**Replies:** 2\
**Last updated:** [February 1, 2023, 3:55am UTC](https://discourse.julialang.org/t/help-in-optim-optimize-structure-of-code-and-help/93656 "2023-02-01T03:55:49Z")

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I have a code taht is more or less like this: fixed parameters \\alpha, \\beta... that never changes #then I have vector of parameters I want to calibrate (theta) and target (mom\_data) theta = \[ \*vector of parameters to …

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## [Offline package installation with download URL via Artifacts.toml](https://discourse.julialang.org/t/offline-package-installation-with-download-url-via-artifacts-toml/55501)

<div class="topic-metadata">

**Author:** [@Kihang](https://discourse.julialang.org/u/Kihang)\
**Replies:** 1\
**Last updated:** [February 1, 2023, 3:00am UTC](https://discourse.julialang.org/t/offline-package-installation-with-download-url-via-artifacts-toml/55501 "2023-02-01T03:00:39Z")

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Hello All, I have some questions for installation package offline environments. First, I can get package jl folder through Git using PC that can use Internet and I moved the folder to offline system then I installed su…

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## [Updating an old project to modern broadcasting](https://discourse.julialang.org/t/updating-an-old-project-to-modern-broadcasting/93843)

<div class="topic-metadata">

**Author:** [@kiranshila](https://discourse.julialang.org/u/kiranshila)\
**Replies:** 2\
**Last updated:** [February 1, 2023, 12:14am UTC](https://discourse.julialang.org/t/updating-an-old-project-to-modern-broadcasting/93843 "2023-02-01T00:14:33Z")

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I’ve been tasked with updating an old 0.6 project to modern Julia and am having a really hard time working with the new broadcasting interface. The old code defined Base.broadcast!(f, output::BroadcastTypes, args...) =…

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## [Forecasting time series data with neural ordinary differential equations in Julia](https://discourse.julialang.org/t/forecasting-time-series-data-with-neural-ordinary-differential-equations-in-julia/92977)

<div class="topic-metadata">

**Author:** [@dmjalal90](https://discourse.julialang.org/u/dmjalal90)\
**Replies:** 27\
**Last updated:** [January 31, 2023, 11:50pm UTC](https://discourse.julialang.org/t/forecasting-time-series-data-with-neural-ordinary-differential-equations-in-julia/92977 "2023-01-31T23:50:03Z")

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Dear all, I am a new user of Julia and following a tutorial on NeuralODE (please see the tutorial: Experiments with Neural ODEs in Julia). How can I forecast ENSO data (time series data in a CSV file) using the above t…

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## [Disable warnings in \`Plots\`](https://discourse.julialang.org/t/disable-warnings-in-plots/93838)

<div class="topic-metadata">

**Author:** [@Torkel](https://discourse.julialang.org/u/Torkel)\
**Replies:** 3\
**Last updated:** [January 31, 2023, 11:34pm UTC](https://discourse.julialang.org/t/disable-warnings-in-plots/93838 "2023-01-31T23:34:50Z")

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I am using Plots to plot(data,options...). This produces tons of Warnings like: ┌ Warning: Indices Base.OneTo(7) of attribute \`fillcolor\` does not match data indices 1:6. └ @ Plots ~/.julia/packages/Plots/AAjgN/src/util…

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## [Update xlims in interactive GLMakie](https://discourse.julialang.org/t/update-xlims-in-interactive-glmakie/93825)

<div class="topic-metadata">

**Author:** [@mreichMPI-BGC](https://discourse.julialang.org/u/mreichMPI-BGC)\
**Replies:** 5\
**Last updated:** [January 31, 2023, 10:49pm UTC](https://discourse.julialang.org/t/update-xlims-in-interactive-glmakie/93825 "2023-01-31T22:49:51Z")

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I have the question how to make xlims and ylims update automatically when an Observable changes. For instance: x=1:10 |\> collect |\> Observable fig, ax, plt = scatter(x, @lift($x .^ 2)) fig Updating x does not lead to …

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## [Questions About Saveat](https://discourse.julialang.org/t/questions-about-saveat/93839)

<div class="topic-metadata">

**Author:** [@yoshi](https://discourse.julialang.org/u/yoshi)\
**Replies:** 1\
**Last updated:** [January 31, 2023, 9:21pm UTC](https://discourse.julialang.org/t/questions-about-saveat/93839 "2023-01-31T21:21:42Z")

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When I run the following code with saveat I get an error: using DifferentialEquations function f(du,u,p,t) du\[1\] = 1.01\*u\[1\] du\[2\] = 2.01\*u\[2\] end ICs = \[.1 3\]; tspan = (0.0f0,5.0f0); SaveTimes = \[0.1:.33:4.0\]; prob…

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## [How do I define my own type based on Julia's pre-existing type?](https://discourse.julialang.org/t/how-do-i-define-my-own-type-based-on-julias-pre-existing-type/93835)

<div class="topic-metadata">

**Author:** [@Ahmed\_Salih](https://discourse.julialang.org/u/Ahmed_Salih)\
**Replies:** 4\
**Last updated:** [January 31, 2023, 8:54pm UTC](https://discourse.julialang.org/t/how-do-i-define-my-own-type-based-on-julias-pre-existing-type/93835 "2023-01-31T20:54:49Z")

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Hello! I am trying to perform a simple experiment and need some help. I wish to make a copy of the AbstractVector type as such: struct AbstractVectorCopy{T} \<: AbstractVector{T} field::AbstractVector{T} end Then…

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## [Create polygon in LibGEOS.jl](https://discourse.julialang.org/t/create-polygon-in-libgeos-jl/93483)

<div class="topic-metadata">

**Author:** [@SDA](https://discourse.julialang.org/u/SDA)\
**Replies:** 4\
**Last updated:** [January 31, 2023, 7:35pm UTC](https://discourse.julialang.org/t/create-polygon-in-libgeos-jl/93483 "2023-01-31T19:35:39Z")

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I am trying to create a polygon using LibGEOS.jl. The docs give an example for the case where the polygon vertices are input manually: using LibGEOS p1 = readgeom(“POLYGON((0 0,1 0,1 1,0 0))”) I would like to instea…

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## [How do I update an environment in Julia?](https://discourse.julialang.org/t/how-do-i-update-an-environment-in-julia/93826)

<div class="topic-metadata">

**Author:** [@danielsoutar](https://discourse.julialang.org/u/danielsoutar)\
**Replies:** 2\
**Last updated:** [January 31, 2023, 5:32pm UTC](https://discourse.julialang.org/t/how-do-i-update-an-environment-in-julia/93826 "2023-01-31T17:32:03Z")

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Hi, a colleague of mine and I were arguing about environments in Julia in a project we have. Let’s say we have a standard project: $ ls Project.toml ... Manifest.toml ... src test ... I might have some version restric…

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## [Making an efficient function for ignoring unsupported kwargs](https://discourse.julialang.org/t/making-an-efficient-function-for-ignoring-unsupported-kwargs/93794)

<div class="topic-metadata">

**Author:** [@tictaccat](https://discourse.julialang.org/u/tictaccat)\
**Replies:** 4\
**Last updated:** [January 31, 2023, 4:45pm UTC](https://discourse.julialang.org/t/making-an-efficient-function-for-ignoring-unsupported-kwargs/93794 "2023-01-31T16:45:59Z")

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Given a function f that may accept some keyword arguments, I want to make a function g that accepts any keyword arguments and ignores those that are unsupported by f. Below is code that achieves this goal: function igno…

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## [Senior Julia engineer](https://discourse.julialang.org/t/senior-julia-engineer/93144)

<div class="topic-metadata">

**Author:** [@Maria\_Mukhina](https://discourse.julialang.org/u/Maria_Mukhina)\
**Replies:** 1\
**Last updated:** [January 18, 2023, 5:21pm UTC](https://discourse.julialang.org/t/senior-julia-engineer/93144 "2023-01-18T17:21:15Z")

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Hey there! BHFT is looking for a Senior Julia developer! We are looking for a strong developer with a vast experience in designing and debugging streaming services to join a leading HFT company. We expect that the cand…

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## [How to get ordering of constraints when calling eval\_constraint?](https://discourse.julialang.org/t/how-to-get-ordering-of-constraints-when-calling-eval-constraint/93772)

<div class="topic-metadata">

**Author:** [@hugh\_man](https://discourse.julialang.org/u/hugh_man)\
**Replies:** 2\
**Last updated:** [January 31, 2023, 4:00pm UTC](https://discourse.julialang.org/t/how-to-get-ordering-of-constraints-when-calling-eval-constraint/93772 "2023-01-31T16:00:09Z")

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Hello, I have a large JuMP model constructed programmatically as a function of some input data. My ultimate goal is to plug in arbitrary values into the variables and evaluate the values of the constraints. To accompi…

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## [Can I integrate 2 functions simultaneously in DifferentialEquations.jl?](https://discourse.julialang.org/t/can-i-integrate-2-functions-simultaneously-in-differentialequations-jl/93801)

<div class="topic-metadata">

**Author:** [@shaurya](https://discourse.julialang.org/u/shaurya)\
**Replies:** 3\
**Last updated:** [January 31, 2023, 3:53pm UTC](https://discourse.julialang.org/t/can-i-integrate-2-functions-simultaneously-in-differentialequations-jl/93801 "2023-01-31T15:53:21Z")

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I have 2 coupled systems of differential equations, used for spacecraft simulation, which are to be integrated simultaneously: In this system, omega\_i and epsilon\_j are the variables. (i belongs to {1,2,3} and j be…

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## [\`rrule\` for \`StructArrays\`](https://discourse.julialang.org/t/rrule-for-structarrays/93820)

<div class="topic-metadata">

**Author:** [@theogf](https://discourse.julialang.org/u/theogf)\
**Replies:** 1\
**Last updated:** [January 31, 2023, 3:07pm UTC](https://discourse.julialang.org/t/rrule-for-structarrays/93820 "2023-01-31T15:07:50Z")

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Hi! I am trying to write the correct rrule for StructArray. However I struggle quite a lot with some of the errors returned by test\_rrule. Here is what I got so far: ProjectTo(::StructArray{T}) where {T} = ProjectTo{S…

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## [Help me convert a weird data type into booleans!](https://discourse.julialang.org/t/help-me-convert-a-weird-data-type-into-booleans/93704)

<div class="topic-metadata">

**Author:** [@clouedoc](https://discourse.julialang.org/u/clouedoc)\
**Replies:** 6\
**Last updated:** [January 31, 2023, 1:34pm UTC](https://discourse.julialang.org/t/help-me-convert-a-weird-data-type-into-booleans/93704 "2023-01-31T13:34:58Z")

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Hello there, I’ve been struggling to learn Julia for the last few days. I’m especially interested in machine learning. So, I’ve managed to train a decision tree model, and I’ve been able to make some predictions. How…

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## [Logscale on negative real axis](https://discourse.julialang.org/t/logscale-on-negative-real-axis/93814)

<div class="topic-metadata">

**Author:** [@gvdeynde](https://discourse.julialang.org/u/gvdeynde)\
**Replies:** 6\
**Last updated:** [January 31, 2023, 11:41am UTC](https://discourse.julialang.org/t/logscale-on-negative-real-axis/93814 "2023-01-31T11:41:12Z")

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Hi all I have a function, foo(x), which is defined only on the negative real axis. The range is quite wide and I want to plot it in log-scale, say from x=-1.0e7 to x=-1.0e-7. How can I “transform” the axis in Makie to a…

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## [@test\_logs behavior when using with\_logger](https://discourse.julialang.org/t/test-logs-behavior-when-using-with-logger/80239)

<div class="topic-metadata">

**Author:** [@jdlara-berkeley](https://discourse.julialang.org/u/jdlara-berkeley)\
**Replies:** 3\
**Last updated:** [January 31, 2023, 10:09am UTC](https://discourse.julialang.org/t/test-logs-behavior-when-using-with-logger/80239 "2023-01-31T10:09:17Z")

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When trying to test for logging inside of a custom logger, the @test\_logs macro seems to be unable to capture the logs. Here is an MWE using Test using Logging @test\_logs (:error, "test") match\_mode = :any Logging.with…

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