# Latest

**URL:** https://discourse.julialang.org/latest.md?page=1449

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

**Page:** 1450

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## [Handling the error "HTTP.ExceptionRequest.StatusError"](https://discourse.julialang.org/t/handling-the-error-http-exceptionrequest-statuserror/57777)

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**Author:** [@Nash](https://discourse.julialang.org/u/Nash)\
**Replies:** 3\
**Last updated:** [March 23, 2021, 12:53pm UTC](https://discourse.julialang.org/t/handling-the-error-http-exceptionrequest-statuserror/57777 "2021-03-23T12:53:40Z")

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In the process of getting price data from Yahoo Finance, sometimes a ticker is missing. In that case, I get the error HTTP.ExceptionRequest.StatusError How do I handle this error such that, when it occurs, I can continu…

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## [Quasi-newton nonlinear solver for sparse jacobian](https://discourse.julialang.org/t/quasi-newton-nonlinear-solver-for-sparse-jacobian/57672)

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**Author:** [@RangeFu](https://discourse.julialang.org/u/RangeFu)\
**Replies:** 20\
**Last updated:** [March 23, 2021, 12:40pm UTC](https://discourse.julialang.org/t/quasi-newton-nonlinear-solver-for-sparse-jacobian/57672 "2021-03-23T12:40:14Z")

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Hi community, I was wondering if there is a sparse-optimized quasi-newton solver in the Julia ecosystem. This question was motivated by the undocumented broyden solver in NLsolve.jl. This solver requires the inverse of …

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## [Array of structures vs. Structures of arrays](https://discourse.julialang.org/t/array-of-structures-vs-structures-of-arrays/56936)

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**Author:** [@shiroghost](https://discourse.julialang.org/u/shiroghost)\
**Replies:** 10\
**Last updated:** [March 23, 2021, 12:38pm UTC](https://discourse.julialang.org/t/array-of-structures-vs-structures-of-arrays/56936 "2021-03-23T12:38:19Z")

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Hi all, I am trying my first steps with CUDA.jl and I have a question about memory layout. I have a simple unmutable structure, for example: struct Angles x::SVector{3, Float64} end I have operations like function …

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## [Correct way to fetch results from distributed processes while also printing progress?](https://discourse.julialang.org/t/correct-way-to-fetch-results-from-distributed-processes-while-also-printing-progress/57779)

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**Author:** [@rlrs](https://discourse.julialang.org/u/rlrs)\
**Replies:** 0\
**Last updated:** [March 23, 2021, 12:31pm UTC](https://discourse.julialang.org/t/correct-way-to-fetch-results-from-distributed-processes-while-also-printing-progress/57779 "2021-03-23T12:31:10Z")

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This is my setup: I’m running a distributed computation where Futures return their own local results, and potential further (recursive) Futures that they have created. The initial Futures are stored in an array on the m…

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## [What does a question mark mean next to type in a DataFrame?](https://discourse.julialang.org/t/what-does-a-question-mark-mean-next-to-type-in-a-dataframe/57774)

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**Author:** [@Nash](https://discourse.julialang.org/u/Nash)\
**Replies:** 2\
**Last updated:** [March 23, 2021, 11:54am UTC](https://discourse.julialang.org/t/what-does-a-question-mark-mean-next-to-type-in-a-dataframe/57774 "2021-03-23T11:54:30Z")

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What does Float64(?) mean, for example, in a DataFrame?

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## [Julia Distributed, redundant iterations appearing](https://discourse.julialang.org/t/julia-distributed-redundant-iterations-appearing/57682)

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**Author:** [@WouterJRV](https://discourse.julialang.org/u/WouterJRV)\
**Replies:** 4\
**Last updated:** [March 23, 2021, 11:36am UTC](https://discourse.julialang.org/t/julia-distributed-redundant-iterations-appearing/57682 "2021-03-23T11:36:30Z")

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I ran mpiexec -n $nprocs julia --project myfile.jl on a cluster, where myfile.jl has the following form using Distributed; using Dates; using JLD2; using LaTeXStrings @everywhere begin using SharedArrays; using Quan…

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## [Calculating the branch current](https://discourse.julialang.org/t/calculating-the-branch-current/57768)

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**Author:** [@priod](https://discourse.julialang.org/u/priod)\
**Replies:** 3\
**Last updated:** [March 23, 2021, 11:32am UTC](https://discourse.julialang.org/t/calculating-the-branch-current/57768 "2021-03-23T11:32:55Z")

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I need some help in calculating the branch current flows using the PowerModels package, and matpower casses.

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## [Specify Julia enviroment in PyJulia?](https://discourse.julialang.org/t/specify-julia-enviroment-in-pyjulia/57776)

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**Author:** [@Ahmed\_Salih](https://discourse.julialang.org/u/Ahmed_Salih)\
**Replies:** 0\
**Last updated:** [March 23, 2021, 10:52am UTC](https://discourse.julialang.org/t/specify-julia-enviroment-in-pyjulia/57776 "2021-03-23T10:52:37Z")

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Hi! I am using PyJulia to link Python with Julia. In Python I am using a virtual enviroment (not Conda based) inside of Python in which I am calling PyJulia - this works completely fine. Inside of the virtual enviromen…

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## [Upper bound algorithm how can I translate my algorithm in julia code](https://discourse.julialang.org/t/upper-bound-algorithm-how-can-i-translate-my-algorithm-in-julia-code/57729)

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**Author:** [@Yasmine\_123](https://discourse.julialang.org/u/Yasmine_123)\
**Replies:** 2\
**Last updated:** [March 23, 2021, 9:18am UTC](https://discourse.julialang.org/t/upper-bound-algorithm-how-can-i-translate-my-algorithm-in-julia-code/57729 "2021-03-23T09:18:51Z")

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Hi everyone, I am a new user of julia. I should write an optimistic algorithm given the similarity parameters sij and the number of families r, partition the m product types into r families G1, …, Gr, each of size m/r,…

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## [Why is the function of a callable object (Functor) allocating?](https://discourse.julialang.org/t/why-is-the-function-of-a-callable-object-functor-allocating/57773)

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**Author:** [@zsoerenm](https://discourse.julialang.org/u/zsoerenm)\
**Replies:** 1\
**Last updated:** [March 23, 2021, 8:21am UTC](https://discourse.julialang.org/t/why-is-the-function-of-a-callable-object-functor-allocating/57773 "2021-03-23T08:21:10Z")

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I’m experimenting with functors. I noticed that when I pass an array to the functor, that it is allocating memory even if it should be possible without memory allocation. Here is a simplified version: struct Foo end (:…

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## [Multithreaded random: different behaviour in Julia \>= 1.5 (not just different stream)](https://discourse.julialang.org/t/multithreaded-random-different-behaviour-in-julia-1-5-not-just-different-stream/57291)

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**Author:** [@sylvaticus](https://discourse.julialang.org/u/sylvaticus)\
**Replies:** 6\
**Last updated:** [March 23, 2021, 7:20am UTC](https://discourse.julialang.org/t/multithreaded-random-different-behaviour-in-julia-1-5-not-just-different-stream/57291 "2021-03-23T07:20:45Z")

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Hi, I just realised that my solution below for multithreaded random number generators works only in Julia \>= 1.5. In particular the test of “CASE A” fails, i.e. the two repetitions issue the same number. Is there a way…

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## [Link back to main repo on each page in Documenter.jl](https://discourse.julialang.org/t/link-back-to-main-repo-on-each-page-in-documenter-jl/57444)

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**Author:** [@sloede](https://discourse.julialang.org/u/sloede)\
**Replies:** 6\
**Last updated:** [March 23, 2021, 6:32am UTC](https://discourse.julialang.org/t/link-back-to-main-repo-on-each-page-in-documenter-jl/57444 "2021-03-23T06:32:56Z")

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I am sure this has been asked before, but I was not able to find it here or in the Documenter issues: Is there a way to include a link back to the main repository on each page of Documenter.jl? I know that there’s the E…

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## [First example of Makie failed?](https://discourse.julialang.org/t/first-example-of-makie-failed/54926)

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**Author:** [@Carsten](https://discourse.julialang.org/u/Carsten)\
**Replies:** 8\
**Last updated:** [March 23, 2021, 6:17am UTC](https://discourse.julialang.org/t/first-example-of-makie-failed/54926 "2021-03-23T06:17:11Z")

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I running the first example of the documentation of Makie using GLMakie using AbstractPlotting AbstractPlotting.inline!(true) points = \[Point2f0(cos(t), sin(t)) for t in LinRange(0, 2pi, 20)\]; colors = 1:20; figure, axi…

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## [Renaming master to main -- Julia-specific experience](https://discourse.julialang.org/t/renaming-master-to-main-julia-specific-experience/57723)

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**Author:** [@fonsp](https://discourse.julialang.org/u/fonsp)\
**Replies:** 8\
**Last updated:** [March 23, 2021, 6:16am UTC](https://discourse.julialang.org/t/renaming-master-to-main-julia-specific-experience/57723 "2021-03-23T06:16:23Z")

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For package maintainers considering renaming their default branch from master to main: I did it last month (Pluto.jl and PlutoUI.jl), and here are my Julia-specific experiences! The main takeaway for me was: the rename…

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## [Is there an implementation of Trefethen's contour integrals for evaluating \[1 - exp(-x)\] / x as x-\>0?](https://discourse.julialang.org/t/is-there-an-implementation-of-trefethens-contour-integrals-for-evaluating-1-exp-x-x-as-x-0/57680)

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**Author:** [@liuyxpp](https://discourse.julialang.org/u/liuyxpp)\
**Replies:** 15\
**Last updated:** [March 23, 2021, 5:07am UTC](https://discourse.julialang.org/t/is-there-an-implementation-of-trefethens-contour-integrals-for-evaluating-1-exp-x-x-as-x-0/57680 "2021-03-23T05:07:16Z")

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This kind of evaluation frequently occurs in numerical analysis, and I believe there should be an implementation in Julia. If so, I am happy to use it rather than re-invent the wheel:) Thanks!

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## [Experiments with VectorizationBase](https://discourse.julialang.org/t/experiments-with-vectorizationbase/57475)

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**Author:** [@GunnarFarneback](https://discourse.julialang.org/u/GunnarFarneback)\
**Replies:** 6\
**Last updated:** [March 23, 2021, 3:17am UTC](https://discourse.julialang.org/t/experiments-with-vectorizationbase/57475 "2021-03-23T03:17:12Z")

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I’ve been trying out VectorizationBase for some low-level SIMD coding. This has worked but I suspect there may be better ways to go about it or at least I need some pointers for how to adapt to some recent changes in thi…

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## [When developing a package, how do you access files in the package directory structure?](https://discourse.julialang.org/t/when-developing-a-package-how-do-you-access-files-in-the-package-directory-structure/57750)

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**Author:** [@3ArnjN](https://discourse.julialang.org/u/3ArnjN)\
**Replies:** 3\
**Last updated:** [March 23, 2021, 12:18am UTC](https://discourse.julialang.org/t/when-developing-a-package-how-do-you-access-files-in-the-package-directory-structure/57750 "2021-03-23T00:18:53Z")

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I am working on a package that’s supposed to download and use files in the data directory inside the package directory structure. Originally, I was using ./data as a path of the data directory. That worked fine for me a…

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## [VS Code Intellisense for custom package](https://discourse.julialang.org/t/vs-code-intellisense-for-custom-package/57496)

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**Author:** [@asyrov](https://discourse.julialang.org/u/asyrov)\
**Replies:** 5\
**Last updated:** [March 23, 2021, 12:11am UTC](https://discourse.julialang.org/t/vs-code-intellisense-for-custom-package/57496 "2021-03-23T00:11:34Z")

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I’m developing a custom package which is located in some folder (other than .julia/packages/...). This package’s root folder added to JULIA\_LOAD\_PATH as: export JULIA\_LOAD\_PATH=$HOME/local/packages:$JULIA\_LOAD\_PATH It …

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## [Error in Agent pos attribute Prisoner’s Dilemma Agents](https://discourse.julialang.org/t/error-in-agent-pos-attribute-prisoner-s-dilemma-agents/57655)

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**Author:** [@Ola\_Megahed](https://discourse.julialang.org/u/Ola_Megahed)\
**Replies:** 2\
**Last updated:** [March 22, 2021, 11:59pm UTC](https://discourse.julialang.org/t/error-in-agent-pos-attribute-prisoner-s-dilemma-agents/57655 "2021-03-22T23:59:18Z")

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I am trying to duplicate the demographic Prisoner’s Dilemma by Epstein. I am having a code problem related to moving the agent according to my below function. basically I canot get the attribute position. function movem…

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## [Problem allocating vector components](https://discourse.julialang.org/t/problem-allocating-vector-components/57756)

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**Author:** [@leopdsf](https://discourse.julialang.org/u/leopdsf)\
**Replies:** 2\
**Last updated:** [March 22, 2021, 11:43pm UTC](https://discourse.julialang.org/t/problem-allocating-vector-components/57756 "2021-03-22T23:43:25Z")

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Hello, there! I’m studying the spacing s between eigenvalues of 2\\times2 matrices. My code is the following (some description lies in the comments): using Distributions using LinearAlgebra d1 = Normal(0.0,1) d2 = Norm…

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## [Foreach for macros?](https://discourse.julialang.org/t/foreach-for-macros/57678)

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**Author:** [@turquoise](https://discourse.julialang.org/u/turquoise)\
**Replies:** 9\
**Last updated:** [March 22, 2021, 11:16pm UTC](https://discourse.julialang.org/t/foreach-for-macros/57678 "2021-03-22T23:16:59Z")

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I am trying to define a foreach macro that works with macros. That is: @foreach @amacro expr1 expr2 ... Should give @amacro(expr1) @amacro(expr2) ... I couldn’t make this work even with a single expr input. I defin…

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## [Debug package test with VSCode](https://discourse.julialang.org/t/debug-package-test-with-vscode/57758)

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**Author:** [@tpgillam](https://discourse.julialang.org/u/tpgillam)\
**Replies:** 0\
**Last updated:** [March 22, 2021, 11:18pm UTC](https://discourse.julialang.org/t/debug-package-test-with-vscode/57758 "2021-03-22T23:18:44Z")

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Hello - I’m currently trying to use the debugger in the context of a package’s tests. Specifically, I would like to hit a breakpoint that I have placed in one of the source files in the module. Currently I haven’t been …

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## ["Zipped" loops in test sets: a bad design pattern?](https://discourse.julialang.org/t/zipped-loops-in-test-sets-a-bad-design-pattern/57685)

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**Author:** [@Jollywatt](https://discourse.julialang.org/u/Jollywatt)\
**Replies:** 8\
**Last updated:** [March 22, 2021, 9:41pm UTC](https://discourse.julialang.org/t/zipped-loops-in-test-sets-a-bad-design-pattern/57685 "2021-03-22T21:41:47Z")

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I’m (ab)using Julia’s testing interface to verify mathematical propositions for many randomly generated samples. I find myself using the following pattern a lot: @testset "definitions" begin for x in rand(N) ... @t…

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## [What is the most efficient binary representation of unsigned integers in Julia?](https://discourse.julialang.org/t/what-is-the-most-efficient-binary-representation-of-unsigned-integers-in-julia/57465)

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**Author:** [@Volker](https://discourse.julialang.org/u/Volker)\
**Replies:** 17\
**Last updated:** [March 22, 2021, 9:02pm UTC](https://discourse.julialang.org/t/what-is-the-most-efficient-binary-representation-of-unsigned-integers-in-julia/57465 "2021-03-22T21:02:50Z")

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Hello everybody, I would like to know what is the most efficient binary representation in Julia? My use case is to convert an unsigned integer into a binary representation, then to mutate the elements of this binary rep…

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## [Using anonymous Functions to avoid type dispatch](https://discourse.julialang.org/t/using-anonymous-functions-to-avoid-type-dispatch/57749)

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**Author:** [@nben](https://discourse.julialang.org/u/nben)\
**Replies:** 0\
**Last updated:** [March 22, 2021, 8:52pm UTC](https://discourse.julialang.org/t/using-anonymous-functions-to-avoid-type-dispatch/57749 "2021-03-22T20:52:10Z")

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This question is about the merits of a methods of avoiding type dispatch in some low-level functions. I’ve included the context below; though the question itself can probably be understood and answered without the contex…

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## [VegaLite vlplot basic usage, encoding](https://discourse.julialang.org/t/vegalite-vlplot-basic-usage-encoding/57700)

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**Author:** [@nsajko](https://discourse.julialang.org/u/nsajko)\
**Replies:** 1\
**Last updated:** [March 22, 2021, 7:01pm UTC](https://discourse.julialang.org/t/vegalite-vlplot-basic-usage-encoding/57700 "2021-03-22T19:01:27Z")

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I’m new to both Vega Lite and VegaLite.jl, and I’m confused about exactly how is vlplot supposed to work. The VegaLite documentation seems to consist mostly of examples and lacks a more systematic approach to documentati…

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## [Is it possible to store the .julia folder in another directory?](https://discourse.julialang.org/t/is-it-possible-to-store-the-julia-folder-in-another-directory/57526)

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**Author:** [@Volker](https://discourse.julialang.org/u/Volker)\
**Replies:** 2\
**Last updated:** [March 22, 2021, 6:59pm UTC](https://discourse.julialang.org/t/is-it-possible-to-store-the-julia-folder-in-another-directory/57526 "2021-03-22T18:59:17Z")

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Is it possible to store the .julia folder in another directory, so that multiple user can share the same folder and that it isn’t stored on the system drive (C: of windows)?

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## [Add to subplots within a loop using Plots.jl?](https://discourse.julialang.org/t/add-to-subplots-within-a-loop-using-plots-jl/57739)

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**Author:** [@mihalybaci](https://discourse.julialang.org/u/mihalybaci)\
**Replies:** 2\
**Last updated:** [March 22, 2021, 6:36pm UTC](https://discourse.julialang.org/t/add-to-subplots-within-a-loop-using-plots-jl/57739 "2021-03-22T18:36:57Z")

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I am trying to plot some data I have and am having trouble with using subplots. The way things are structured, I need to be able to add data to each subplot incrementally within a loop, then combine into a final plot aft…

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## [Filter a dataframe based on a dictionary](https://discourse.julialang.org/t/filter-a-dataframe-based-on-a-dictionary/57738)

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**Author:** [@mkarikom](https://discourse.julialang.org/u/mkarikom)\
**Replies:** 2\
**Last updated:** [March 22, 2021, 6:10pm UTC](https://discourse.julialang.org/t/filter-a-dataframe-based-on-a-dictionary/57738 "2021-03-22T18:10:34Z")

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Is it possible to filter a data frame based on a dictionary whose keys are a subset of the columns and whose values match the dict? For example, something like this (does not work): df = DataFrame(a=\[1,2,3\],b=\["a","b",…

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## [Is anyone up for collaborating on a vectorized (portfolio) backtesting library?](https://discourse.julialang.org/t/is-anyone-up-for-collaborating-on-a-vectorized-portfolio-backtesting-library/57720)

<div class="topic-metadata">

**Author:** [@itchingpixels](https://discourse.julialang.org/u/itchingpixels)\
**Replies:** 7\
**Last updated:** [March 22, 2021, 5:18pm UTC](https://discourse.julialang.org/t/is-anyone-up-for-collaborating-on-a-vectorized-portfolio-backtesting-library/57720 "2021-03-22T17:18:55Z")

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Hi! I just replied on another thread - I’ve started working on a vectorized (both single asset and portfolio) backtesting framework. I think it could be a low hanging fruit (it’s really not rocket science), high leverag…

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