# Latest

**URL:** https://discourse.julialang.org/latest.md?page=1820

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

**Page:** 1821

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## [Realtime plotting](https://discourse.julialang.org/t/realtime-plotting/15638)

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**Author:** [@ufechner7](https://discourse.julialang.org/u/ufechner7)\
**Replies:** 9\
**Last updated:** [February 19, 2020, 9:39pm UTC](https://discourse.julialang.org/t/realtime-plotting/15638 "2020-02-19T21:39:15Z")

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Hello, I want to plot real-time flight control data to get a better and faster understanding of the performance of our flight controllers. The incoming data stream might be decoded in a C-function (because it already e…

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## [Potential bug related to initialization of a quadratic program](https://discourse.julialang.org/t/potential-bug-related-to-initialization-of-a-quadratic-program/34848)

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**Author:** [@DR59](https://discourse.julialang.org/u/DR59)\
**Replies:** 8\
**Last updated:** [February 19, 2020, 8:52pm UTC](https://discourse.julialang.org/t/potential-bug-related-to-initialization-of-a-quadratic-program/34848 "2020-02-19T20:52:41Z")

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Hi all, Consider the code below (a convex, quadratically constraint, quadratic program I pulled out of a hat). As it stands, it runs fine. However, if I comment out the for loop (i.e. I don’t manually set the starting v…

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## [How to get the first state of a iterator?](https://discourse.julialang.org/t/how-to-get-the-first-state-of-a-iterator/34846)

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**Author:** [@matthieu](https://discourse.julialang.org/u/matthieu)\
**Replies:** 5\
**Last updated:** [February 19, 2020, 8:39pm UTC](https://discourse.julialang.org/t/how-to-get-the-first-state-of-a-iterator/34846 "2020-02-19T20:39:02Z")

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I need to create a vector with the states of an iterator for which the element satisfies a certain condition. However, to do that, I would need to know the first state of an iterator (i.e. the default argument of iterat…

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## [TypeError using ODEs in Turing.jl](https://discourse.julialang.org/t/typeerror-using-odes-in-turing-jl/34857)

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**Author:** [@virgile-baudrot](https://discourse.julialang.org/u/virgile-baudrot)\
**Replies:** 2\
**Last updated:** [February 19, 2020, 8:33pm UTC](https://discourse.julialang.org/t/typeerror-using-odes-in-turing-jl/34857 "2020-02-19T20:33:27Z")

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Hi all, I try using ODEs within Turing model, but I have the following error: TypeError: in typeassert, expected Float64, got ForwardDiff.Dual{Nothing,Float64,1} Here is my code: function myODE(du,u,p,t) du\[1\] = …

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## [Filter dict and change its keys](https://discourse.julialang.org/t/filter-dict-and-change-its-keys/34873)

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**Author:** [@rvignolo](https://discourse.julialang.org/u/rvignolo)\
**Replies:** 5\
**Last updated:** [February 19, 2020, 7:14pm UTC](https://discourse.julialang.org/t/filter-dict-and-change-its-keys/34873 "2020-02-19T19:14:19Z")

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Is is possible to filter a dictionary and change its keys elegantly? julia\> dict = Dict{Tuple{Symbol,Symbol},Expr}((:X₁, :X₁) =\> :(σX(σ\[1\], X₁)), (:X₁, :X₂) =\> :(σX(σ\[1\], X₁)),(:X₂, :X₂) =\> :(σX(σ\[2\], X₂)),(:X₃, :X₃) =\> …

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## [Allocations in Zygote for a simple derivative](https://discourse.julialang.org/t/allocations-in-zygote-for-a-simple-derivative/34871)

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**Author:** [@edwinb-ai](https://discourse.julialang.org/u/edwinb-ai)\
**Replies:** 0\
**Last updated:** [February 19, 2020, 5:41pm UTC](https://discourse.julialang.org/t/allocations-in-zygote-for-a-simple-derivative/34871 "2020-02-19T17:41:57Z")

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Hello everyone, somewhat new to Julia and very new to Zygote. I want to use Zygote’s AD functionality to compute derivatives of some simple functions, like in the following code using Zygote using Random using Benchmark…

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## [Broadcast with container for multidimensional array](https://discourse.julialang.org/t/broadcast-with-container-for-multidimensional-array/34825)

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**Author:** [@MaxPauer](https://discourse.julialang.org/u/MaxPauer)\
**Replies:** 3\
**Last updated:** [February 19, 2020, 4:56pm UTC](https://discourse.julialang.org/t/broadcast-with-container-for-multidimensional-array/34825 "2020-02-19T16:56:25Z")

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Hi, I’ve got a container type for a multidimensional array, and I want to redirect the iterate function to the ‘inner’ array. This works fine, except it does not preserve dimensions when combined with a broadcast call. …

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## [Julia-vscode on MacOs vs Windows](https://discourse.julialang.org/t/julia-vscode-on-macos-vs-windows/29718)

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**Author:** [@Dito](https://discourse.julialang.org/u/Dito)\
**Replies:** 9\
**Last updated:** [February 19, 2020, 2:10pm UTC](https://discourse.julialang.org/t/julia-vscode-on-macos-vs-windows/29718 "2020-02-19T14:10:23Z")

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When I execute file (F5 or Command Palette\>Julia: Execute File) on MacOS - REPL terminal shows me all code I’ve written - evaluates and shows all lines But on Windows 10 the same terminal acts like C++ terminal - It …

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## [Congratulations to VideoIO and Makie maintainers](https://discourse.julialang.org/t/congratulations-to-videoio-and-makie-maintainers/34844)

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**Author:** [@johnh](https://discourse.julialang.org/u/johnh)\
**Replies:** 0\
**Last updated:** [February 19, 2020, 11:55am UTC](https://discourse.julialang.org/t/congratulations-to-videoio-and-makie-maintainers/34844 "2020-02-19T11:55:30Z")

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Quite often in the past I have moaned on here about VideoIO not working to read data from a webcam. I have filed several issues on the VideoIO repository. I am very pleased to say that I loaded VideoIO and Makie on a De…

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## [Is there a streamlines function/package?](https://discourse.julialang.org/t/is-there-a-streamlines-function-package/34800)

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**Author:** [@timmm](https://discourse.julialang.org/u/timmm)\
**Replies:** 9\
**Last updated:** [February 19, 2020, 10:28am UTC](https://discourse.julialang.org/t/is-there-a-streamlines-function-package/34800 "2020-02-19T10:28:04Z")

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Does anyone know of a package to compute 3D streamlines in Julia? Like Matlab’s: Compute 3-D streamline data - MATLAB stream3 - MathWorks Deutschland I specifically want to get the XYZ data describing the streamlines. …

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## [Not working: \`\`redirect\_stdout(IOBuffer()) do ... end\`\`](https://discourse.julialang.org/t/not-working-redirect-stdout-iobuffer-do-end/34841)

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**Author:** [@schlichtanders](https://discourse.julialang.org/u/schlichtanders)\
**Replies:** 0\
**Last updated:** [February 19, 2020, 7:17am UTC](https://discourse.julialang.org/t/not-working-redirect-stdout-iobuffer-do-end/34841 "2020-02-19T07:17:03Z")

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Just wanted to use redirect\_stdout function on IOBuffer but this fails… can we transform an IOBuffer to stream type recognized by redirect\_stdout?

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## [Published VS unpublished // registered vs unregistered](https://discourse.julialang.org/t/published-vs-unpublished-registered-vs-unregistered/34838)

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**Author:** [@markushhh](https://discourse.julialang.org/u/markushhh)\
**Replies:** 4\
**Last updated:** [February 19, 2020, 7:11am UTC](https://discourse.julialang.org/t/published-vs-unpublished-registered-vs-unregistered/34838 "2020-02-19T07:11:20Z")

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I read a couple of times that “people” tend to trust registered packages. Where does the difference in trust come from? Is a registered package checked for harmful code? Do I miss a point?

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## [How do I use packages from the web in my project?](https://discourse.julialang.org/t/how-do-i-use-packages-from-the-web-in-my-project/34660)

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**Author:** [@Kuh\_Tornado](https://discourse.julialang.org/u/Kuh_Tornado)\
**Replies:** 2\
**Last updated:** [February 19, 2020, 7:09am UTC](https://discourse.julialang.org/t/how-do-i-use-packages-from-the-web-in-my-project/34660 "2020-02-19T07:09:14Z")

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Hi there, I’m trying to make my first steps in Julia and as a simple project I want to create a plot from a pre existing CSV file. I saw that there is a CSV package, but how can I import it? The documentation seems to …

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## [Executing Packages and Directories](https://discourse.julialang.org/t/executing-packages-and-directories/34819)

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**Author:** [@hieronimo](https://discourse.julialang.org/u/hieronimo)\
**Replies:** 3\
**Last updated:** [February 19, 2020, 7:03am UTC](https://discourse.julialang.org/t/executing-packages-and-directories/34819 "2020-02-19T07:03:19Z")

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In Python, one can run a program by package name, file name, directory name or zip file name. Also, one can run commands from stdin (e.g. by pipelines) link In Julia, we can run commands from stdin but it isn’t mentione…

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## [Functions in function args?](https://discourse.julialang.org/t/functions-in-function-args/34777)

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**Author:** [@nmatzke](https://discourse.julialang.org/u/nmatzke)\
**Replies:** 3\
**Last updated:** [February 19, 2020, 4:11am UTC](https://discourse.julialang.org/t/functions-in-function-args/34777 "2020-02-19T04:11:36Z")

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Hi all! I am wondering – in R, you can default function argument defaults with functions, e.g. tmpfun ← function(a, b=2\*a) { return(a+b) } tmpfun(a=1) Returns: 3 …is anything like this possible in Julia? It’s not…

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## [ANN: OnlinePackage 0.2](https://discourse.julialang.org/t/ann-onlinepackage-0-2/34840)

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**Author:** [@bramtayl](https://discourse.julialang.org/u/bramtayl)\
**Replies:** 0\
**Last updated:** [February 19, 2020, 3:48am UTC](https://discourse.julialang.org/t/ann-onlinepackage-0-2/34840 "2020-02-19T03:48:25Z")

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https://bramtayl.github.io/OnlinePackage.jl/latest/ Now works with GitHub actions instead of travis. Will automatically generate and upload SSH keys to your GitHub repos. This is necessary to host documentation. This ve…

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## [What would be the best way / command to bechmark Geopandas vs VegaLite?](https://discourse.julialang.org/t/what-would-be-the-best-way-command-to-bechmark-geopandas-vs-vegalite/34779)

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**Author:** [@Aizzaac](https://discourse.julialang.org/u/Aizzaac)\
**Replies:** 3\
**Last updated:** [February 19, 2020, 1:47am UTC](https://discourse.julialang.org/t/what-would-be-the-best-way-command-to-bechmark-geopandas-vs-vegalite/34779 "2020-02-19T01:47:25Z")

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Hi I have plotted a choropleth map using Geopandas (Python) and Vegalite (Julia). I want to benchmark both of them (ease of use, speed, etc). I am very interested in speed. So maybe a @time or @time\_ns or tic() toc(),…

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## [Ccall help](https://discourse.julialang.org/t/ccall-help/34785)

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**Author:** [@bramtayl](https://discourse.julialang.org/u/bramtayl)\
**Replies:** 8\
**Last updated:** [February 19, 2020, 1:30am UTC](https://discourse.julialang.org/t/ccall-help/34785 "2020-02-19T01:30:37Z")

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Hi all, I’m trying to get OnlinePackage to be able to post a package on github, but also set up the necessary SSH keys to get documenter building. I had it working on travis, but now I’m trying to get it work with githu…

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## [Is it possible to use batching in Flux for sequences of different lengths?](https://discourse.julialang.org/t/is-it-possible-to-use-batching-in-flux-for-sequences-of-different-lengths/34594)

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**Author:** [@jmeeks29ig](https://discourse.julialang.org/u/jmeeks29ig)\
**Replies:** 3\
**Last updated:** [February 19, 2020, 12:32am UTC](https://discourse.julialang.org/t/is-it-possible-to-use-batching-in-flux-for-sequences-of-different-lengths/34594 "2020-02-19T00:32:56Z")

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I have sequences that are of the dimensions 8 by N, where N is a number fluctuating between 1 and 400. I would like to be able to do batch processing on these sequences, but have not had any luck in doing so inside of Fl…

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## [Newbie : Accessing DataFrame with row and column names](https://discourse.julialang.org/t/newbie-accessing-dataframe-with-row-and-column-names/34832)

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**Author:** [@benibilme](https://discourse.julialang.org/u/benibilme)\
**Replies:** 5\
**Last updated:** [February 19, 2020, 12:23am UTC](https://discourse.julialang.org/t/newbie-accessing-dataframe-with-row-and-column-names/34832 "2020-02-19T00:23:52Z")

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Hello, I am complete newbie/convert to Julia also to Datascience. I am following a tutorial on probability. I would like to create so called a probability matrix with DataFrames. Probabiliy matrix in the example proble…

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## [When plotting, option "showaxis" does not accept "Symbol" or "String" type](https://discourse.julialang.org/t/when-plotting-option-showaxis-does-not-accept-symbol-or-string-type/34782)

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**Author:** [@tferic](https://discourse.julialang.org/u/tferic)\
**Replies:** 2\
**Last updated:** [February 18, 2020, 11:00pm UTC](https://discourse.julialang.org/t/when-plotting-option-showaxis-does-not-accept-symbol-or-string-type/34782 "2020-02-18T23:00:52Z")

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Hi, I am using Julia 1.0.3 in JuliaBox. I am facing an error when trying to use the “showaxis” option in plotting. I am trying to hide the labels of the x-axis, and display the labels of the y-axis. According to the d…

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## [Dynamically assign variables in a function](https://discourse.julialang.org/t/dynamically-assign-variables-in-a-function/34833)

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**Author:** [@linwaytin](https://discourse.julialang.org/u/linwaytin)\
**Replies:** 2\
**Last updated:** [February 18, 2020, 10:19pm UTC](https://discourse.julialang.org/t/dynamically-assign-variables-in-a-function/34833 "2020-02-18T22:19:31Z")

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I would like to assign variables in functions. For example, function func(p) a = A(p) b = B(p) c = C(p) # Then do something using a, b, c end Those a, b, c are parameters I want to use in the function, and they depend …

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## ["LoadError: invalid redefinition of constant" when creating new Distribution](https://discourse.julialang.org/t/loaderror-invalid-redefinition-of-constant-when-creating-new-distribution/34786)

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**Author:** [@Arrigo\_Benedetti](https://discourse.julialang.org/u/Arrigo_Benedetti)\
**Replies:** 3\
**Last updated:** [February 18, 2020, 9:51pm UTC](https://discourse.julialang.org/t/loaderror-invalid-redefinition-of-constant-when-creating-new-distribution/34786 "2020-02-18T21:51:24Z")

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I am trying to create a new distribution (bivariate Projected Normal) using skellam.jl as an example, however I am getting this error: push!(LOAD\_PATH, ".") using Revise using ProjectedNormal ┌ Info: Precompiling Proj…

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## [Is there a faster way to extract single rows of a dataframe than the filter function](https://discourse.julialang.org/t/is-there-a-faster-way-to-extract-single-rows-of-a-dataframe-than-the-filter-function/34821)

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**Author:** [@Julia1](https://discourse.julialang.org/u/Julia1)\
**Replies:** 3\
**Last updated:** [February 18, 2020, 9:50pm UTC](https://discourse.julialang.org/t/is-there-a-faster-way-to-extract-single-rows-of-a-dataframe-than-the-filter-function/34821 "2020-02-18T21:50:02Z")

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Hi how’s it going, here is the code I’m currently using: df is a 1 row dataframe. df2 is a multiple row dataframe x= filter(row → row\[Symbol(‘ID’)\]\[1\]==df\[Symbol(“ID”)\]\[1\], df2\]) So essentially I’m trying to do a loo…

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## [Error reported in a blank line (MethodError: no method matching getindex(::Float64, ::UnitRange{Int64})](https://discourse.julialang.org/t/error-reported-in-a-blank-line-methoderror-no-method-matching-getindex-float64-unitrange-int64/34766)

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**Author:** [@1634](https://discourse.julialang.org/u/1634)\
**Replies:** 5\
**Last updated:** [February 18, 2020, 9:46pm UTC](https://discourse.julialang.org/t/error-reported-in-a-blank-line-methoderror-no-method-matching-getindex-float64-unitrange-int64/34766 "2020-02-18T21:46:56Z")

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Question solved: At the end this is found to be due to multiplying a constant with a vector, while the error report is a bit distracting (in line much ). for i in 1:nDemes println("deme### ", i) NDeme = …

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## [Delete rows in DataFrame Conditionally](https://discourse.julialang.org/t/delete-rows-in-dataframe-conditionally/34774)

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**Author:** [@aedunn12](https://discourse.julialang.org/u/aedunn12)\
**Replies:** 4\
**Last updated:** [February 18, 2020, 8:36pm UTC](https://discourse.julialang.org/t/delete-rows-in-dataframe-conditionally/34774 "2020-02-18T20:36:37Z")

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I’m trying to delete specific rows in my DataFrame based on conditionals of the row above. In my data, there is a repeated row of the same time point at each time that a medication is administered. My goal is to delete a…

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## [Is there any completion plugin for Emacs?](https://discourse.julialang.org/t/is-there-any-completion-plugin-for-emacs/14758)

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**Author:** [@sheepduke](https://discourse.julialang.org/u/sheepduke)\
**Replies:** 18\
**Last updated:** [February 18, 2020, 8:36pm UTC](https://discourse.julialang.org/t/is-there-any-completion-plugin-for-emacs/14758 "2020-02-18T20:36:24Z")

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Hi there, The Julia REPL is really awesome, quiet comparable to what Common Lisp has. However the code completion tool is rather weak compared with SLIME. I wonder if there is any existing (or ongoing) code completion…

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## [What is replacement for Not column selection in DataFrames (inverted index) in DataFrames v0.20.0?](https://discourse.julialang.org/t/what-is-replacement-for-not-column-selection-in-dataframes-inverted-index-in-dataframes-v0-20-0/34823)

<div class="topic-metadata">

**Author:** [@js135005](https://discourse.julialang.org/u/js135005)\
**Replies:** 6\
**Last updated:** [February 18, 2020, 7:25pm UTC](https://discourse.julialang.org/t/what-is-replacement-for-not-column-selection-in-dataframes-inverted-index-in-dataframes-v0-20-0/34823 "2020-02-18T19:25:54Z")

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I was making extensive of the Not function for column selection in DataFrames. However this is deprecated in v0.20.0 and I haven’t yet found how to do the equivalent in the latest documentation. Indeed the DataFrames do…

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## [Macro cannot see variables in calling function's scope](https://discourse.julialang.org/t/macro-cannot-see-variables-in-calling-functions-scope/34806)

<div class="topic-metadata">

**Author:** [@brownlight](https://discourse.julialang.org/u/brownlight)\
**Replies:** 4\
**Last updated:** [February 18, 2020, 7:00pm UTC](https://discourse.julialang.org/t/macro-cannot-see-variables-in-calling-functions-scope/34806 "2020-02-18T19:00:38Z")

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Scenario: A variable exists in the (local) scope of a function. func1 calls macro passing it the variable as a parameter. But, the macro can’t see the variable. I have run into this issue when migrating code from versio…

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## [Error in callback differential equations](https://discourse.julialang.org/t/error-in-callback-differential-equations/34781)

<div class="topic-metadata">

**Author:** [@mleprovost](https://discourse.julialang.org/u/mleprovost)\
**Replies:** 2\
**Last updated:** [February 18, 2020, 6:21pm UTC](https://discourse.julialang.org/t/error-in-callback-differential-equations/34781 "2020-02-18T18:21:23Z")

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Hello, I am getting the error Event repeated at the same time. Please report this error when I use DifferentialEquations.jl with ContinuousCallback with rootfinder active. Is there a way to go around? Unfortunately I d…

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