# Latest

**URL:** https://discourse.julialang.org/latest.md?page=1511

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

**Page:** 1512

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## [Position at ARPA-e](https://discourse.julialang.org/t/position-at-arpa-e/54028)

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**Author:** [@viralbshah](https://discourse.julialang.org/u/viralbshah)\
**Replies:** 0\
**Last updated:** [January 27, 2021, 2:51am UTC](https://discourse.julialang.org/t/position-at-arpa-e/54028 "2021-01-27T02:51:58Z")

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This is a really exciting position for someone who wants to work at the intersection of computing and energy/climate change. -viral – https://arpa-e.energy.gov/career/job-opportunities#op-152897-program-director PD “…

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## [Cannot find output of run() command](https://discourse.julialang.org/t/cannot-find-output-of-run-command/50788)

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**Author:** [@ruysan](https://discourse.julialang.org/u/ruysan)\
**Replies:** 2\
**Last updated:** [January 27, 2021, 2:33am UTC](https://discourse.julialang.org/t/cannot-find-output-of-run-command/50788 "2021-01-27T02:33:41Z")

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Hi! I am generating a shell cut command with a series of arguments parsed from a file header. the output of the command it redirected to a file: cut -f 1-9,14,15 input\_file \> output\_file I can print the command itsel…

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## [Can't do statistics with Dates?](https://discourse.julialang.org/t/cant-do-statistics-with-dates/54020)

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**Author:** [@joa-quim](https://discourse.julialang.org/u/joa-quim)\
**Replies:** 4\
**Last updated:** [January 27, 2021, 1:35am UTC](https://discourse.julialang.org/t/cant-do-statistics-with-dates/54020 "2021-01-27T01:35:28Z")

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julia\> d = diff(collect(Dates.Date(1980,1,1):Dates.Month(3):Dates.Date(2019,1,1))) 156-element Vector{Day}: 91 days 91 days 92 days 92 days ... julia\> mean(d) ERROR: InexactError: Int64(91.31410256410257)

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## [ModelingToolkit.jl periodic callbacks -- discrete controllers and model transitions from events](https://discourse.julialang.org/t/modelingtoolkit-jl-periodic-callbacks-discrete-controllers-and-model-transitions-from-events/53933)

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**Author:** [@Allan\_Baker](https://discourse.julialang.org/u/Allan_Baker)\
**Replies:** 2\
**Last updated:** [January 27, 2021, 1:19am UTC](https://discourse.julialang.org/t/modelingtoolkit-jl-periodic-callbacks-discrete-controllers-and-model-transitions-from-events/53933 "2021-01-27T01:19:42Z")

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How would one use the ModelingToolkit to model a physical system but interface it to a discrete controller? I don’t see this in any of the examples? (But maybe I’m not looking in the right spot.) Is it just a callback…

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## [Interpolation of heatmap with semi-transparent colormaps in Makie](https://discourse.julialang.org/t/interpolation-of-heatmap-with-semi-transparent-colormaps-in-makie/53947)

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**Author:** [@sfmiller940](https://discourse.julialang.org/u/sfmiller940)\
**Replies:** 5\
**Last updated:** [January 26, 2021, 9:58pm UTC](https://discourse.julialang.org/t/interpolation-of-heatmap-with-semi-transparent-colormaps-in-makie/53947 "2021-01-26T21:58:35Z")

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Hello, I’ve been try make heatmaps using colormaps that go from transparent to either white or black. The interpolation works as expected for black but it looks terrible for white. Here’s some sample code with the res…

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## [Sum(log.(p \* C)) is 2 to 4 times slower than in NumPy](https://discourse.julialang.org/t/sum-log-p-c-is-2-to-4-times-slower-than-in-numpy/53960)

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**Author:** [@ForceBru](https://discourse.julialang.org/u/ForceBru)\
**Replies:** 19\
**Last updated:** [January 26, 2021, 11:39pm UTC](https://discourse.julialang.org/t/sum-log-p-c-is-2-to-4-times-slower-than-in-numpy/53960 "2021-01-26T23:39:03Z")

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I’m coming from Python and trying to port my Python code to Julia to gain more performance. I want to compute a lot of log-likelihoods in a loop, so I need a fast function that computes the log-likelihood. The computati…

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## [Propagating uncertainty of estimated ODE parameters in turing.jl](https://discourse.julialang.org/t/propagating-uncertainty-of-estimated-ode-parameters-in-turing-jl/53718)

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**Author:** [@EvoArt](https://discourse.julialang.org/u/EvoArt)\
**Replies:** 5\
**Last updated:** [January 26, 2021, 11:20pm UTC](https://discourse.julialang.org/t/propagating-uncertainty-of-estimated-ode-parameters-in-turing-jl/53718 "2021-01-26T23:20:30Z")

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Hello all, I have been using turing to estimate parameters of logistic growth curve ODEs, using data from bacterial growth experiments. Since I have replicate growth curves for each treatment, I am interested in the pos…

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## [Version \* does not match other versions](https://discourse.julialang.org/t/version-does-not-match-other-versions/53995)

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**Author:** [@bluesmoon](https://discourse.julialang.org/u/bluesmoon)\
**Replies:** 8\
**Last updated:** [January 26, 2021, 10:47pm UTC](https://discourse.julialang.org/t/version-does-not-match-other-versions/53995 "2021-01-26T22:47:11Z")

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I’m using Julia 1.5.3 Trying to run my tests locally, and I get this error about PyCall version conflicts. My own package has a PyCall version dependency of \* whereas some other package (not one of mine) has a PyCall v…

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## [Passing around large structs efficiently](https://discourse.julialang.org/t/passing-around-large-structs-efficiently/53975)

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**Author:** [@liuyxpp](https://discourse.julialang.org/u/liuyxpp)\
**Replies:** 6\
**Last updated:** [January 26, 2021, 2:03pm UTC](https://discourse.julialang.org/t/passing-around-large-structs-efficiently/53975 "2021-01-26T14:03:02Z")

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I have a struct struct Chain N x y z end where x, y, and z are vectors of length N. I have a function to process a Chain instance function foo1(chain) for i in 1:chain.N for j in (i+1):chain.N …

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## [Problems to build GR](https://discourse.julialang.org/t/problems-to-build-gr/53981)

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**Author:** [@angeloaliano1](https://discourse.julialang.org/u/angeloaliano1)\
**Replies:** 12\
**Last updated:** [January 26, 2021, 8:50pm UTC](https://discourse.julialang.org/t/problems-to-build-gr/53981 "2021-01-26T20:50:00Z")

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Compiling gr() the core is not reset. The error is this: using Plots gr() x=0:0.01:2\*π y=sin.(x) plot(x,y) SystemError: opening file "C:\\\\Users\\\\Usuário\\\\AppData\\\\Local\\\\Temp\\\\jl\_lyXJ1gB2lS.svg": No such file or direct…

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## [How to convert all nothings in dataframe to missing?](https://discourse.julialang.org/t/how-to-convert-all-nothings-in-dataframe-to-missing/54004)

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**Author:** [@Joe\_Schnetzler](https://discourse.julialang.org/u/Joe_Schnetzler)\
**Replies:** 14\
**Last updated:** [January 26, 2021, 8:43pm UTC](https://discourse.julialang.org/t/how-to-convert-all-nothings-in-dataframe-to-missing/54004 "2021-01-26T20:43:31Z")

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I have a dataframe with a bunch of nothings mixed between union columns, etc. How can I change all nothings to missings efficiently? Thanks! Best, Joe

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## [Pkg cannot find registered packages](https://discourse.julialang.org/t/pkg-cannot-find-registered-packages/54008)

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**Author:** [@SEA](https://discourse.julialang.org/u/SEA)\
**Replies:** 2\
**Last updated:** [January 26, 2021, 7:58pm UTC](https://discourse.julialang.org/t/pkg-cannot-find-registered-packages/54008 "2021-01-26T19:58:13Z")

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From one minute to another, my installation of Julia cannot add packages anymore. I tried reinstalling Julia but to no avail. How can I fix this? (@v1.5) pkg\> add DiffResults Resolving package versions... ERROR: Unsat…

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## [\[ANN\] SumTypes.jl 0.1](https://discourse.julialang.org/t/ann-sumtypes-jl-0-1/47161)

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**Author:** [@Mason](https://discourse.julialang.org/u/Mason)\
**Replies:** 30\
**Last updated:** [January 26, 2021, 5:54pm UTC](https://discourse.julialang.org/t/ann-sumtypes-jl-0-1/47161 "2021-01-26T17:54:48Z")

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Hi everyone, I’ve been playing around a bit lately with the idea of ‘sum types’ (aka tagged unions, or enums in Rust circles). These are quite the hotness these days in functional programming and I kept having trouble fu…

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## [Avoid precompiling dependencies / Good package practice](https://discourse.julialang.org/t/avoid-precompiling-dependencies-good-package-practice/53949)

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**Author:** [@Visipi](https://discourse.julialang.org/u/Visipi)\
**Replies:** 3\
**Last updated:** [January 26, 2021, 5:07pm UTC](https://discourse.julialang.org/t/avoid-precompiling-dependencies-good-package-practice/53949 "2021-01-26T17:07:11Z")

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I’m writing a software package that has some pretty beefy dependencies. Naturally, I’d expect a somewhat slow precompilation. With \_\_precompile\_\_(false) I have a dead time of about 30s, and with \_\_precompile\_\_(true) it’s…

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## [Optim callback function -- how to use optimization variable](https://discourse.julialang.org/t/optim-callback-function-how-to-use-optimization-variable/8807)

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**Author:** [@egcjm](https://discourse.julialang.org/u/egcjm)\
**Replies:** 1\
**Last updated:** [January 26, 2021, 4:45pm UTC](https://discourse.julialang.org/t/optim-callback-function-how-to-use-optimization-variable/8807 "2021-01-26T16:45:50Z")

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The optim callback function seems to operate on the OptimizationState, which provides access to the iteration count (.iteration) and value. Can I access the optimization variable being optimized (i.e. temporary optim.mi…

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## [Optim.jl callback](https://discourse.julialang.org/t/optim-jl-callback/52625)

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**Author:** [@PharmCat](https://discourse.julialang.org/u/PharmCat)\
**Replies:** 1\
**Last updated:** [January 26, 2021, 4:44pm UTC](https://discourse.julialang.org/t/optim-jl-callback/52625 "2021-01-26T16:44:16Z")

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How to work properly with OptimizationState? In docs I found only os.iteration. Some like os.metadata\["x"\] not working with error: type Array has no field metadata Is callback documented anywhere? Thx!

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## [JuliaCon 2021 registration is live!](https://discourse.julialang.org/t/juliacon-2021-registration-is-live/53521)

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**Author:** [@logankilpatrick](https://discourse.julialang.org/u/logankilpatrick)\
**Replies:** 2\
**Last updated:** [January 26, 2021, 4:18pm UTC](https://discourse.julialang.org/t/juliacon-2021-registration-is-live/53521 "2021-01-26T16:18:41Z")

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Hey all, registration for this years JuliaCon is now live: JuliaCon 2021: Registration Direct link to register: JuliaCon 2021 Registration, Wed, Jul 28, 2021 at 7:00 AM | Eventbrite

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## [What is best practice for adding OpenCV as a dependency in a Julia Package?](https://discourse.julialang.org/t/what-is-best-practice-for-adding-opencv-as-a-dependency-in-a-julia-package/53990)

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**Author:** [@Erik\_Engheim](https://discourse.julialang.org/u/Erik_Engheim)\
**Replies:** 7\
**Last updated:** [January 26, 2021, 4:11pm UTC](https://discourse.julialang.org/t/what-is-best-practice-for-adding-opencv-as-a-dependency-in-a-julia-package/53990 "2021-01-26T16:11:05Z")

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I went through the recipe online for building the Julia OpenCV bindings. It is all based on CxxWrap to automatically create the bindings. So I get something locally installed, but I cannot add OpenCV as a dependency to m…

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## [What happened to LinearAlgebra.full?](https://discourse.julialang.org/t/what-happened-to-linearalgebra-full/53984)

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**Author:** [@gedankenexperiment](https://discourse.julialang.org/u/gedankenexperiment)\
**Replies:** 2\
**Last updated:** [January 26, 2021, 3:36pm UTC](https://discourse.julialang.org/t/what-happened-to-linearalgebra-full/53984 "2021-01-26T15:36:01Z")

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Hi, I’m getting an UndefVarError: full not defined for using OrdinaryDiffEq, RecursiveArrayTools,LinearAlgebra const Mx = full(Tridiagonal(\[1.0 for i in 1:N-1\],\[-2.0 for i in 1:N\],\[1.0 for i in 1:N-1\])) coming from th…

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## [How to deal with parameters of the type Vector{Tuple}?](https://discourse.julialang.org/t/how-to-deal-with-parameters-of-the-type-vector-tuple/53968)

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**Author:** [@stefkuypers](https://discourse.julialang.org/u/stefkuypers)\
**Replies:** 4\
**Last updated:** [January 26, 2021, 3:32pm UTC](https://discourse.julialang.org/t/how-to-deal-with-parameters-of-the-type-vector-tuple/53968 "2021-01-26T15:32:12Z")

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Hi, I’m writing some code where I expect a vector of 2-element tuples but I can’t figure out how to type the parameters in such a way that it’s clear what needs to be passed but not so restrictive that type promotion is…

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## [Call OpenCV functions from Julia](https://discourse.julialang.org/t/call-opencv-functions-from-julia/37820)

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**Author:** [@hasanOryx](https://discourse.julialang.org/u/hasanOryx)\
**Replies:** 2\
**Last updated:** [January 26, 2021, 3:21pm UTC](https://discourse.julialang.org/t/call-opencv-functions-from-julia/37820 "2021-01-26T15:21:55Z")

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In this and this the author explaining how to call OpenCV functions from C#. How can I do this from Julia? Here how to make OpenCV C++ project

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## [Opencv help needed for libcbdetect](https://discourse.julialang.org/t/opencv-help-needed-for-libcbdetect/45865)

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**Author:** [@yakir12](https://discourse.julialang.org/u/yakir12)\
**Replies:** 1\
**Last updated:** [January 26, 2021, 3:18pm UTC](https://discourse.julialang.org/t/opencv-help-needed-for-libcbdetect/45865 "2021-01-26T15:18:15Z")

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Hi! I would love to be able to auto-detect checkerboards in images for image-calibration purposes. One way forward is to utilize https://github.com/ftdlyc/libcbdetect (a C++ implementation of libcbdetect which is in Mat…

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## [Confused about intent of using/import (docs)](https://discourse.julialang.org/t/confused-about-intent-of-using-import-docs/53834)

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**Author:** [@MA\_Laforge](https://discourse.julialang.org/u/MA_Laforge)\
**Replies:** 5\
**Last updated:** [January 26, 2021, 3:16pm UTC](https://discourse.julialang.org/t/confused-about-intent-of-using-import-docs/53834 "2021-01-26T15:16:06Z")

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I was reading the (new v1.7) docs on modules (Standalone using and import): Specifically: Possibly the most common way of loading a module is using ModuleName. This loads the code associated with ModuleName, and brin…

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## [Removing characters from String](https://discourse.julialang.org/t/removing-characters-from-string/53962)

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**Author:** [@LinasBa](https://discourse.julialang.org/u/LinasBa)\
**Replies:** 15\
**Last updated:** [January 26, 2021, 3:04pm UTC](https://discourse.julialang.org/t/removing-characters-from-string/53962 "2021-01-26T15:04:18Z")

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Hello, I would like to remove some characters from String, but that seems to be really complicated in Julia :frowning: Example: str = "ž1ž1" r = r"1" idx = eachmatch(r, str) .|\> o -\> o.offset result = String(deleteat!…

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## [Using callback functions via CallbackSet](https://discourse.julialang.org/t/using-callback-functions-via-callbackset/53985)

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**Author:** [@JuliaCantisan](https://discourse.julialang.org/u/JuliaCantisan)\
**Replies:** 1\
**Last updated:** [January 26, 2021, 2:48pm UTC](https://discourse.julialang.org/t/using-callback-functions-via-callbackset/53985 "2021-01-26T14:48:39Z")

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Hi everyone, I’m trying to add two DiscreteCallbacks to my integrator using CallbackSet. Each of them seem to work when the other one is not present, but the first one does not work when the second one is present. This …

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## [Graphing a large, tiled graph with PlotlyJS](https://discourse.julialang.org/t/graphing-a-large-tiled-graph-with-plotlyjs/53979)

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**Author:** [@Smack](https://discourse.julialang.org/u/Smack)\
**Replies:** 5\
**Last updated:** [January 26, 2021, 2:30pm UTC](https://discourse.julialang.org/t/graphing-a-large-tiled-graph-with-plotlyjs/53979 "2021-01-26T14:30:13Z")

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Hi, I am trying to plot multiple scatter plots and save them in a file (svg/pdf) After creating the plots and saving them in a variable, I find the only way I can tile them is with the splatter operator: \[plots\_array……

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## [Import CSV where the rows are separated by brackets](https://discourse.julialang.org/t/import-csv-where-the-rows-are-separated-by-brackets/53971)

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**Author:** [@Okarin99](https://discourse.julialang.org/u/Okarin99)\
**Replies:** 1\
**Last updated:** [January 26, 2021, 1:50pm UTC](https://discourse.julialang.org/t/import-csv-where-the-rows-are-separated-by-brackets/53971 "2021-01-26T13:50:26Z")

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Hey, is there a simple way to import a csv file in which each row is separated by brackets? My file looks like this: \[Energie in MeV, y\_na, u\_(y\_na)\] \[0.09760250284217108, 0.3514244536139464, 0.013170188213585452\] \[0.…

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## [VectorContinuousCallback creating too many time steps?](https://discourse.julialang.org/t/vectorcontinuouscallback-creating-too-many-time-steps/53940)

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**Author:** [@jonniedie](https://discourse.julialang.org/u/jonniedie)\
**Replies:** 1\
**Last updated:** [January 26, 2021, 1:32pm UTC](https://discourse.julialang.org/t/vectorcontinuouscallback-creating-too-many-time-steps/53940 "2021-01-26T13:32:54Z")

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I have a VectorContinuousCallback of four variables. As you can see below, things are pretty monotonic and should be relatively straightforward for rootfinding. For some reason, though, my simulation is taking a few …

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## [Local and global variables with the same name: ERROR: UndefVarError: x not defined](https://discourse.julialang.org/t/local-and-global-variables-with-the-same-name-error-undefvarerror-x-not-defined/53951)

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**Author:** [@Shuhua](https://discourse.julialang.org/u/Shuhua)\
**Replies:** 3\
**Last updated:** [January 26, 2021, 12:12pm UTC](https://discourse.julialang.org/t/local-and-global-variables-with-the-same-name-error-undefvarerror-x-not-defined/53951 "2021-01-26T12:12:25Z")

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In REPL julia\> x = randn(3); julia\> function add\_one() x = x .+ 1 @show x end add\_one (generic function with 1 method) julia\> add\_one() ERROR: UndefVarError: x not defined Stacktrace: \[1\]…

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## [RCall vscode REPL crash](https://discourse.julialang.org/t/rcall-vscode-repl-crash/46128)

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**Author:** [@Donut\_Meepo](https://discourse.julialang.org/u/Donut_Meepo)\
**Replies:** 7\
**Last updated:** [January 26, 2021, 10:25am UTC](https://discourse.julialang.org/t/rcall-vscode-repl-crash/46128 "2021-01-26T10:25:45Z")

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I was trying to using RCall in VSCode’s Julia REPL. It crashes. But if I start a REPL from terminal it works fine. (Note: the rfunctions.jl below only has one line of using RCall so that I can capture the error. Sinc…

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