# Latest

**URL:** https://discourse.julialang.org/latest.md?page=1466

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

**Page:** 1467

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## [How to use an event driven architecture in Julia?](https://discourse.julialang.org/t/how-to-use-an-event-driven-architecture-in-julia/56748)

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**Author:** [@BryanB](https://discourse.julialang.org/u/BryanB)\
**Replies:** 8\
**Last updated:** [March 9, 2021, 8:01am UTC](https://discourse.julialang.org/t/how-to-use-an-event-driven-architecture-in-julia/56748 "2021-03-09T08:01:00Z")

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Hello everyone! I’m an equities and options trader with a basic understanding of Python and JavaScript. The little I’ve seen of Julia so far has been amazing and I’m hoping to explore working with financial data in Julia…

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## [Is there a tool for 3D Delaunay and Voronoi tessellations?](https://discourse.julialang.org/t/is-there-a-tool-for-3d-delaunay-and-voronoi-tessellations/19503)

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**Author:** [@afas](https://discourse.julialang.org/u/afas)\
**Replies:** 12\
**Last updated:** [March 9, 2021, 7:47am UTC](https://discourse.julialang.org/t/is-there-a-tool-for-3d-delaunay-and-voronoi-tessellations/19503 "2021-03-09T07:47:44Z")

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I am currently migrating all my research software to Julia, and so far I am very pleased with the experience and the relative easiness in transporting code. I have, however, reached a bottleneck cause I can’t seem to be…

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## [Looking for a time-series jump test package](https://discourse.julialang.org/t/looking-for-a-time-series-jump-test-package/56773)

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**Author:** [@Yifan\_Liu](https://discourse.julialang.org/u/Yifan_Liu)\
**Replies:** 4\
**Last updated:** [March 9, 2021, 7:40am UTC](https://discourse.julialang.org/t/looking-for-a-time-series-jump-test-package/56773 "2021-03-09T07:40:37Z")

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Are there any Julia packages that can detect time-series jumps?

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## [Seek advice on displaying clickable N by N images](https://discourse.julialang.org/t/seek-advice-on-displaying-clickable-n-by-n-images/56709)

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**Author:** [@hpw](https://discourse.julialang.org/u/hpw)\
**Replies:** 3\
**Last updated:** [March 9, 2021, 4:36am UTC](https://discourse.julialang.org/t/seek-advice-on-displaying-clickable-n-by-n-images/56709 "2021-03-09T04:36:22Z")

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I would like to build an N by N squares laid out in a grid form. Each square has a background color and an image at the center. No distance between two squares. If one of the images is clicked, an event signal is emit…

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## [Macro: is it possible to receive a function and manipulate its arguments?](https://discourse.julialang.org/t/macro-is-it-possible-to-receive-a-function-and-manipulate-its-arguments/56781)

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**Author:** [@iHany](https://discourse.julialang.org/u/iHany)\
**Replies:** 2\
**Last updated:** [March 9, 2021, 3:56am UTC](https://discourse.julialang.org/t/macro-is-it-possible-to-receive-a-function-and-manipulate-its-arguments/56781 "2021-03-09T03:56:15Z")

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Hi. I’m a newbie of Julia macro. I’d like to know whether it’s possible to get a function and manipulate its arguments by macro. For example, something like this. @mymacro func(a, b) # == func(a+b, a-b)

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## [How can you guarantee that all the functions / branches / loops in your package has been tested?](https://discourse.julialang.org/t/how-can-you-guarantee-that-all-the-functions-branches-loops-in-your-package-has-been-tested/55835)

<div class="topic-metadata">

**Author:** [@Lian\_Yunlong](https://discourse.julialang.org/u/Lian_Yunlong)\
**Replies:** 11\
**Last updated:** [March 9, 2021, 3:17am UTC](https://discourse.julialang.org/t/how-can-you-guarantee-that-all-the-functions-branches-loops-in-your-package-has-been-tested/55835 "2021-03-09T03:17:34Z")

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Is there any automated testing method for a rather complicated package? Probably a macro that injects some logging commands to each function / if-else branch / for-loop and produce a statistical analysis of the coverage …

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## [Pkg does not install any packages, complains about Artifacts](https://discourse.julialang.org/t/pkg-does-not-install-any-packages-complains-about-artifacts/56782)

<div class="topic-metadata">

**Author:** [@hei06j](https://discourse.julialang.org/u/hei06j)\
**Replies:** 0\
**Last updated:** [March 9, 2021, 3:05am UTC](https://discourse.julialang.org/t/pkg-does-not-install-any-packages-complains-about-artifacts/56782 "2021-03-09T03:05:19Z")

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Hi, it seems that I cannot install any packages with the package manager. I get the same error for any package: (@v1.5) pkg\> add Pluto Resolving package versions... ERROR: Unsatisfiable requirements detected for pack…

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## [Anyone has implemented Kernel SVD in this ICLR 2019 paper?](https://discourse.julialang.org/t/anyone-has-implemented-kernel-svd-in-this-iclr-2019-paper/56780)

<div class="topic-metadata">

**Author:** [@Lian\_Yunlong](https://discourse.julialang.org/u/Lian_Yunlong)\
**Replies:** 0\
**Last updated:** [March 9, 2021, 2:52am UTC](https://discourse.julialang.org/t/anyone-has-implemented-kernel-svd-in-this-iclr-2019-paper/56780 "2021-03-09T02:52:15Z")

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Hello experts, recently I am trying out Flux.jl to initiate a research project on ML. I quickly ran into the issue of network compression and knowledge distillation. I have a background in physics and I have heard about…

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## [Tips on integrals using DiffEqOperators](https://discourse.julialang.org/t/tips-on-integrals-using-diffeqoperators/56769)

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**Author:** [@sdwfrost](https://discourse.julialang.org/u/sdwfrost)\
**Replies:** 3\
**Last updated:** [March 9, 2021, 12:28am UTC](https://discourse.julialang.org/t/tips-on-integrals-using-diffeqoperators/56769 "2021-03-09T00:28:56Z")

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I’m trying to use DiffEqOperators to define the Kermack-McKendrick model, which is basically a PDE generalization of the simple SIR epidemiological model: The equation for I is a PDE, while that for S and R is an ODE …

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## [General questions from Python user](https://discourse.julialang.org/t/general-questions-from-python-user/55475)

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**Author:** [@lancejnelson](https://discourse.julialang.org/u/lancejnelson)\
**Replies:** 59\
**Last updated:** [March 8, 2021, 10:49pm UTC](https://discourse.julialang.org/t/general-questions-from-python-user/55475 "2021-03-08T22:49:39Z")

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Hi all, I heard from a friend that this is a great place to have conversations about Julia. I’ve been using Python for years but am intrigued by Julia. Big picture question: Will I have to try really hard to get Jul…

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## [Progressbar for multiple workers -- connecting workers to RemoteChannel](https://discourse.julialang.org/t/progressbar-for-multiple-workers-connecting-workers-to-remotechannel/56683)

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**Author:** [@jlbosse](https://discourse.julialang.org/u/jlbosse)\
**Replies:** 6\
**Last updated:** [March 8, 2021, 9:56pm UTC](https://discourse.julialang.org/t/progressbar-for-multiple-workers-connecting-workers-to-remotechannel/56683 "2021-03-08T21:56:38Z")

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I am trying to expand the example given on the ProgressMeter.jl documentation to get a progress bar for a few slow processes that run in parallel. Since there are only few processes, but each of them take a long time I w…

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## [Reduce "overweighted" collection entries to a given weight](https://discourse.julialang.org/t/reduce-overweighted-collection-entries-to-a-given-weight/56444)

<div class="topic-metadata">

**Author:** [@djholiver](https://discourse.julialang.org/u/djholiver)\
**Replies:** 2\
**Last updated:** [March 8, 2021, 9:29pm UTC](https://discourse.julialang.org/t/reduce-overweighted-collection-entries-to-a-given-weight/56444 "2021-03-08T21:29:45Z")

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Hi, I’ve been searching around (statsbase, linearalgebra) for a solution to the following (which I believe is some form of normalisation but I dont know the name) and a Julia implementation. Note that this is a simplif…

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## [The need of (i)fftshift's to compute a PDE using Fourier Transform](https://discourse.julialang.org/t/the-need-of-i-fftshifts-to-compute-a-pde-using-fourier-transform/56587)

<div class="topic-metadata">

**Author:** [@tiago](https://discourse.julialang.org/u/tiago)\
**Replies:** 12\
**Last updated:** [March 8, 2021, 8:54pm UTC](https://discourse.julialang.org/t/the-need-of-i-fftshifts-to-compute-a-pde-using-fourier-transform/56587 "2021-03-08T20:54:50Z")

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Hello, I’m currently writing an algorithm to solve a specific kind of PDE, via Fourier Transform. In the several examples that I saw, the general idea is to transform everything to the frequency domain using an fft, do…

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## [Problems installing registries and IJulia with Julia v1.5.2 in Windows 10 64 bit](https://discourse.julialang.org/t/problems-installing-registries-and-ijulia-with-julia-v1-5-2-in-windows-10-64-bit/49025)

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**Author:** [@dineshgct](https://discourse.julialang.org/u/dineshgct)\
**Replies:** 15\
**Last updated:** [March 8, 2021, 8:35pm UTC](https://discourse.julialang.org/t/problems-installing-registries-and-ijulia-with-julia-v1-5-2-in-windows-10-64-bit/49025 "2021-03-08T20:35:26Z")

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Installation issue - Could anyone help? this is the command i use…but nothing is happening…keep says Installation known registeries… as mentioned below. I get no errors as well… what to do? julia\> using Pkg julia\> Pkg…

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## [Will the new github security policy affect the way we use/develop Julia packages?](https://discourse.julialang.org/t/will-the-new-github-security-policy-affect-the-way-we-use-develop-julia-packages/56677)

<div class="topic-metadata">

**Author:** [@sylvaticus](https://discourse.julialang.org/u/sylvaticus)\
**Replies:** 3\
**Last updated:** [March 8, 2021, 8:28pm UTC](https://discourse.julialang.org/t/will-the-new-github-security-policy-affect-the-way-we-use-develop-julia-packages/56677 "2021-03-08T20:28:31Z")

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I wonder if the new GitHub policy that from 13 August 2021 will disable simple password-based git commands workflow will affect the way we use or develop Julia packages.

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## [Julia on free tier cloud instances](https://discourse.julialang.org/t/julia-on-free-tier-cloud-instances/56692)

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**Author:** [@sschmidhuber](https://discourse.julialang.org/u/sschmidhuber)\
**Replies:** 4\
**Last updated:** [March 8, 2021, 7:45pm UTC](https://discourse.julialang.org/t/julia-on-free-tier-cloud-instances/56692 "2021-03-08T19:45:30Z")

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Hello, I would like to run my little julia application on a free cloud machine. Currently I’m using a AWS EC2 t2.micro machine. Unfortunately the micro instance (1GB memory, 1vCPU) fails on precompilation of DataFrames. …

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## [\[ANN\] Announcing GeoDataFrames.jl](https://discourse.julialang.org/t/ann-announcing-geodataframes-jl/56735)

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**Author:** [@evetion](https://discourse.julialang.org/u/evetion)\
**Replies:** 3\
**Last updated:** [March 8, 2021, 7:13pm UTC](https://discourse.julialang.org/t/ann-announcing-geodataframes-jl/56735 "2021-03-08T19:13:19Z")

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I’d like to announce GeoDataFrames.jl, a Table interface for reading and writing common vector formats, such as shapefiles and geopackages. It’s quite small, as the majority comes from the work in ArchGDAL.jl and GDAL.jl …

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## [Subtyping Dict](https://discourse.julialang.org/t/subtyping-dict/56720)

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**Author:** [@imLew](https://discourse.julialang.org/u/imLew)\
**Replies:** 8\
**Last updated:** [March 8, 2021, 6:44pm UTC](https://discourse.julialang.org/t/subtyping-dict/56720 "2021-03-08T18:44:25Z")

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I’m using Dicts to store the parameters store the parameters of a problem to be solved by an algorithm. There are different types of problems and I would like to use multiple dispatch to organize the code for running the…

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## [ChainRulesCore.rrule for custom struct: does the pullback need to support Composite explicitly?](https://discourse.julialang.org/t/chainrulescore-rrule-for-custom-struct-does-the-pullback-need-to-support-composite-explicitly/56734)

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**Author:** [@yha](https://discourse.julialang.org/u/yha)\
**Replies:** 5\
**Last updated:** [March 8, 2021, 2:53pm UTC](https://discourse.julialang.org/t/chainrulescore-rrule-for-custom-struct-does-the-pullback-need-to-support-composite-explicitly/56734 "2021-03-08T14:53:15Z")

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I’m trying to differentiate code involving GeometryBasics.Point construction (always with two arguments). This seems to allow Zygote to compute the gradient correctly: function ChainRulesCore.rrule(::Type{Point}, x::Nu…

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## [Grouping for color or markers in CairoMakie](https://discourse.julialang.org/t/grouping-for-color-or-markers-in-cairomakie/56728)

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**Author:** [@vjd](https://discourse.julialang.org/u/vjd)\
**Replies:** 6\
**Last updated:** [March 8, 2021, 2:52pm UTC](https://discourse.julialang.org/t/grouping-for-color-or-markers-in-cairomakie/56728 "2021-03-08T14:52:43Z")

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is there a way to groupby a dataframe column passed into color or marker such that each group gets a unique element? or does this have to be done as different scatter! calls for each group ccf = DataFrame(a = 1:4, …

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## [Dependencies when doing distributed](https://discourse.julialang.org/t/dependencies-when-doing-distributed/56736)

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**Author:** [@threadedblue](https://discourse.julialang.org/u/threadedblue)\
**Replies:** 0\
**Last updated:** [March 8, 2021, 2:41pm UTC](https://discourse.julialang.org/t/dependencies-when-doing-distributed/56736 "2021-03-08T14:41:09Z")

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I have a line of code like this: @everywhere include("encounters.jl") The file in question, encounters.jl has in it a line using AAUtils The module AAUtils is installed both locally and remotely. Q: From where is AA…

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## [How to print a tree "vertically" defined by \`AbstractTrees.jl\`](https://discourse.julialang.org/t/how-to-print-a-tree-vertically-defined-by-abstracttrees-jl/56729)

<div class="topic-metadata">

**Author:** [@Shuhua](https://discourse.julialang.org/u/Shuhua)\
**Replies:** 2\
**Last updated:** [March 8, 2021, 1:57pm UTC](https://discourse.julialang.org/t/how-to-print-a-tree-vertically-defined-by-abstracttrees-jl/56729 "2021-03-08T13:57:53Z")

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See the following example. julia\> using AbstractTrees julia\> function AbstractTrees.children(i::Integer) if i \<= 3 return i + 1, i + 2 end return () end julia\> pr…

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## [Implementing SQLite / Spatialite driver](https://discourse.julialang.org/t/implementing-sqlite-spatialite-driver/55840)

<div class="topic-metadata">

**Author:** [@maxfreu](https://discourse.julialang.org/u/maxfreu)\
**Replies:** 13\
**Last updated:** [March 8, 2021, 1:49pm UTC](https://discourse.julialang.org/t/implementing-sqlite-spatialite-driver/55840 "2021-03-08T13:49:43Z")

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Hi! I’m sick of the mess shapefiles create and it itches me to write a package for reading geometries from sqlite files (they proved to be rather small and fast last time I tested). Given the simplicity of the WKB format…

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## [If I have a an object of type \`Array{Float32, 2}\`, using \`eltype\` gives me \`Float3](https://discourse.julialang.org/t/if-i-have-a-an-object-of-type-array-float32-2-using-eltype-gives-me-float3/56733)

<div class="topic-metadata">

**Author:** [@BridgeBot](https://discourse.julialang.org/u/BridgeBot)\
**Replies:** 1\
**Last updated:** [March 8, 2021, 1:45pm UTC](https://discourse.julialang.org/t/if-i-have-a-an-object-of-type-array-float32-2-using-eltype-gives-me-float3/56733 "2021-03-08T13:45:03Z")

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If I have a an object of type Array{Float32, 2}, using eltype gives me Float32, what gives me Array ? Note that the original poster on Slack cannot see your response here on Discourse. Consider transcribing the appropri…

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## [Register a route which takes query parameters and extract those parameters to do the business logic](https://discourse.julialang.org/t/register-a-route-which-takes-query-parameters-and-extract-those-parameters-to-do-the-business-logic/56730)

<div class="topic-metadata">

**Author:** [@ispandey81](https://discourse.julialang.org/u/ispandey81)\
**Replies:** 0\
**Last updated:** [March 8, 2021, 1:06pm UTC](https://discourse.julialang.org/t/register-a-route-which-takes-query-parameters-and-extract-those-parameters-to-do-the-business-logic/56730 "2021-03-08T13:06:49Z")

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I am trying to register a route using HTTP.jl which takes a query parameter and extract that query parameter using HTTP.URIs.queryparams but cant’ get it to work. Any help appreciated. Sample code below. Want to invoke …

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## [Checking if function input is DataFrame](https://discourse.julialang.org/t/checking-if-function-input-is-dataframe/56707)

<div class="topic-metadata">

**Author:** [@jo-fleck](https://discourse.julialang.org/u/jo-fleck)\
**Replies:** 5\
**Last updated:** [March 8, 2021, 12:44pm UTC](https://discourse.julialang.org/t/checking-if-function-input-is-dataframe/56707 "2021-03-08T12:44:05Z")

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I wrote a function which inspects a data frame and, if its content meets certain requirements, sends it to a server. To make sure (new) users can easily understand which aspect of the content needs to be changed in case …

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## [AlgebraOfGraphics: how to add xlabel and ylabel](https://discourse.julialang.org/t/algebraofgraphics-how-to-add-xlabel-and-ylabel/56408)

<div class="topic-metadata">

**Author:** [@phlavenk](https://discourse.julialang.org/u/phlavenk)\
**Replies:** 2\
**Last updated:** [March 8, 2021, 12:29pm UTC](https://discourse.julialang.org/t/algebraofgraphics-how-to-add-xlabel-and-ylabel/56408 "2021-03-08T12:29:52Z")

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I couldn’t find an example of how to add an x-axis label to the algebra flow. For example, in this simple plot, how would I add a “Number of cylinders” x label to both subfigures? using RDatasets: dataset using Algebra…

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## [\[Query.jl\] Way to map many variables to a single function](https://discourse.julialang.org/t/query-jl-way-to-map-many-variables-to-a-single-function/56675)

<div class="topic-metadata">

**Author:** [@Storopoli](https://discourse.julialang.org/u/Storopoli)\
**Replies:** 0\
**Last updated:** [March 7, 2021, 1:29pm UTC](https://discourse.julialang.org/t/query-jl-way-to-map-many-variables-to-a-single-function/56675 "2021-03-07T13:29:50Z")

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Here is the code in DataFrames: @chain DataFrame(tbl) begin dropmissing(\[:NT\_GER, :NT\_FG, :NT\_CE\]) groupby(\[:TP\_SEXO, :CO\_TURNO\_GRADUACAO\], skipmissing=true) combine(nrow, \[:NT\_GER, :NT\_FG, :NT\_C…

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## [Modifiying Julia tuple, Dict and object from C](https://discourse.julialang.org/t/modifiying-julia-tuple-dict-and-object-from-c/56469)

<div class="topic-metadata">

**Author:** [@Clonkk](https://discourse.julialang.org/u/Clonkk)\
**Replies:** 9\
**Last updated:** [March 8, 2021, 8:47am UTC](https://discourse.julialang.org/t/modifiying-julia-tuple-dict-and-object-from-c/56469 "2021-03-08T08:47:43Z")

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Hello, I haven’t seen anything in the documentation so I’m asking here; is there a way to manipulate tuple, Dict and object from C ? I create the Julia type in C using jl\_eval function - I haven’t found another way to …

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## [Worker thread setup in Julia compared to C++/pthreads](https://discourse.julialang.org/t/worker-thread-setup-in-julia-compared-to-c-pthreads/56630)

<div class="topic-metadata">

**Author:** [@paulmelis](https://discourse.julialang.org/u/paulmelis)\
**Replies:** 6\
**Last updated:** [March 8, 2021, 8:16am UTC](https://discourse.julialang.org/t/worker-thread-setup-in-julia-compared-to-c-pthreads/56630 "2021-03-08T08:16:03Z")

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I’m trying to port some code (a 3D renderer) that in C++ uses a simple tasking system to process items of work using multiple OS-level threads. Each item can (and will) take a varying amount of time to process making it …

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