# Latest

**URL:** https://discourse.julialang.org/latest.md?page=1826

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

**Page:** 1827

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## [Parametric type with a constrained NamedTuple](https://discourse.julialang.org/t/parametric-type-with-a-constrained-namedtuple/34511)

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**Author:** [@Tamas\_Papp](https://discourse.julialang.org/u/Tamas_Papp)\
**Replies:** 2\
**Last updated:** [February 12, 2020, 11:15am UTC](https://discourse.julialang.org/t/parametric-type-with-a-constrained-namedtuple/34511 "2020-02-12T11:15:07Z")

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I would like to define a parametric type that constrains a NamedTuple to have values of a certain type, but I am running into a problem. I am not sure if it is a bug, and if there is a workaround (other than specifying t…

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## [How can I get the CS decomposition of a matrix?](https://discourse.julialang.org/t/how-can-i-get-the-cs-decomposition-of-a-matrix/34499)

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**Author:** [@Deniz](https://discourse.julialang.org/u/Deniz)\
**Replies:** 6\
**Last updated:** [February 12, 2020, 10:16am UTC](https://discourse.julialang.org/t/how-can-i-get-the-cs-decomposition-of-a-matrix/34499 "2020-02-12T10:16:16Z")

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There seems to be no function in any well-known Julia library to obtain the CS decomposition of a matrix. There is a function CUNCSD in LAPACK, but it is not available in Julia by default. Maybe I can call that function…

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## [Opening the browser from Julia ... works ... but error](https://discourse.julialang.org/t/opening-the-browser-from-julia-works-but-error/34482)

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**Author:** [@Darione](https://discourse.julialang.org/u/Darione)\
**Replies:** 1\
**Last updated:** [February 12, 2020, 9:06am UTC](https://discourse.julialang.org/t/opening-the-browser-from-julia-works-but-error/34482 "2020-02-12T09:06:00Z")

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Hi all, i was trying to open the browser to a page i have previously created by Julia with this code: @show menu\_file mycommand = \`explorer results\\\\$menu\_file\` run(mycommand) I obtain this error … also if…

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## [Programacion no lineal](https://discourse.julialang.org/t/programacion-no-lineal/34502)

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**Author:** [@WellingtonPerez](https://discourse.julialang.org/u/WellingtonPerez)\
**Replies:** 3\
**Last updated:** [February 12, 2020, 8:37am UTC](https://discourse.julialang.org/t/programacion-no-lineal/34502 "2020-02-12T08:37:12Z")

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estoy tratando de programar un ejercicio no lineal pero me sale el siguiente error LoadError: The solver does not support an objective function of type MathOptInterface.ScalarQuadraticFunction{Float64}.

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## [Managing dependencies in packages](https://discourse.julialang.org/t/managing-dependencies-in-packages/34474)

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**Author:** [@timueh](https://discourse.julialang.org/u/timueh)\
**Replies:** 1\
**Last updated:** [February 12, 2020, 8:30am UTC](https://discourse.julialang.org/t/managing-dependencies-in-packages/34474 "2020-02-12T08:30:25Z")

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How do I account for package dependencies that vary depending on the Julia version when running CI via travis? My situation: The SpecialFunctions package in its latest version 0.10.0 requires Julia 1.3 or above. When wr…

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## [\[ANN\] Tables.jl 1.0 Release](https://discourse.julialang.org/t/ann-tables-jl-1-0-release/34505)

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**Author:** [@quinnj](https://discourse.julialang.org/u/quinnj)\
**Replies:** 0\
**Last updated:** [February 12, 2020, 7:32am UTC](https://discourse.julialang.org/t/ann-tables-jl-1-0-release/34505 "2020-02-12T07:32:47Z")

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Hello all, A new 1.0 release was just registered in the General registry for the Tables.jl package. The API has matured well over the last 1.5 years (since 2018 JuliaCon hackathon!), and we felt like it was time for an…

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## [Optimize performance comparison - Optim.jl vs Scipy](https://discourse.julialang.org/t/optimize-performance-comparison-optim-jl-vs-scipy/12588)

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**Author:** [@tk3369](https://discourse.julialang.org/u/tk3369)\
**Replies:** 15\
**Last updated:** [February 12, 2020, 5:10am UTC](https://discourse.julialang.org/t/optimize-performance-comparison-optim-jl-vs-scipy/12588 "2020-02-12T05:10:15Z")

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I am just starting to learn about optimization. I picked up Optim.jl (great documentation, btw) and tried to do the same thing in Python. It seems that Rosenbrock function is what everyone uses as an example. Perhaps …

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## [Programming Language Checklist](https://discourse.julialang.org/t/programming-language-checklist/34457)

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**Author:** [@johnh](https://discourse.julialang.org/u/johnh)\
**Replies:** 6\
**Last updated:** [February 12, 2020, 4:48am UTC](https://discourse.julialang.org/t/programming-language-checklist/34457 "2020-02-12T04:48:13Z")

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https://www.famicol.in/language\_checklist.html I will start the ball rolling. Any more to check? The name of your language makes it impossible to find on Google

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## [Solve an ODE system parameters](https://discourse.julialang.org/t/solve-an-ode-system-parameters/34498)

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**Author:** [@Lecalvaire](https://discourse.julialang.org/u/Lecalvaire)\
**Replies:** 1\
**Last updated:** [February 12, 2020, 1:51am UTC](https://discourse.julialang.org/t/solve-an-ode-system-parameters/34498 "2020-02-12T01:51:15Z")

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Hello, First of all, I must say that it’s (almost) my first use of the language; I usually use Matlab or Mathematica but for this special purpose I need an open source software, so I give a chance to Julia. Here is my …

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## [Can't capture the output of print() in a worker process](https://discourse.julialang.org/t/cant-capture-the-output-of-print-in-a-worker-process/34335)

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**Author:** [@Alyosha](https://discourse.julialang.org/u/Alyosha)\
**Replies:** 2\
**Last updated:** [February 11, 2020, 10:44pm UTC](https://discourse.julialang.org/t/cant-capture-the-output-of-print-in-a-worker-process/34335 "2020-02-11T22:44:32Z")

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Why is it that when I print() something in a worker process that doesn’t end with a newline char \\n, I don’t capture it in the stdout of the master process, but if I use println() I do? For example consider the followin…

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## [Is there a package for NFAs and DFAs (finite automata)?](https://discourse.julialang.org/t/is-there-a-package-for-nfas-and-dfas-finite-automata/34492)

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**Author:** [@lesshaste](https://discourse.julialang.org/u/lesshaste)\
**Replies:** 0\
**Last updated:** [February 11, 2020, 10:12pm UTC](https://discourse.julialang.org/t/is-there-a-package-for-nfas-and-dfas-finite-automata/34492 "2020-02-11T22:12:04Z")

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I am looking for a Julia package to help me create NFAs and convert them to DFAs. Does such a package exist currently? So far I have been using https://www.gap-system.org/ .

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## [I can't open the notebooks via IJulia](https://discourse.julialang.org/t/i-cant-open-the-notebooks-via-ijulia/34395)

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**Author:** [@Pedro\_Luiz](https://discourse.julialang.org/u/Pedro_Luiz)\
**Replies:** 3\
**Last updated:** [February 10, 2020, 3:07pm UTC](https://discourse.julialang.org/t/i-cant-open-the-notebooks-via-ijulia/34395 "2020-02-10T15:07:04Z")

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julia\> using IJulia julia\> notebook() \[ Info: running setenv(\`'C:\\Users\\Pedro Luiz\\.julia\\conda\\3\\Scripts\\jupyter.exe' notebook\`,\["PATH=C:\\\\Users\\\\Pedro Luiz\\\\.julia\\\\conda\\\\3\\\\Library\\\\bin;C:\\\\Users\\\\Pedro Luiz\\\\.julia…

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## [Fitting a circle/ellipse over an image](https://discourse.julialang.org/t/fitting-a-circle-ellipse-over-an-image/34143)

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**Author:** [@razvangheorghe](https://discourse.julialang.org/u/razvangheorghe)\
**Replies:** 15\
**Last updated:** [February 11, 2020, 7:48pm UTC](https://discourse.julialang.org/t/fitting-a-circle-ellipse-over-an-image/34143 "2020-02-11T19:48:03Z")

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Hello, It would be very useful if I could fit a circle/ellipse over a set of density plots. The images are very noisy, but for most of them, you can vaguely make up the shape of an ellipse. Here’s an example: What …

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## [Defining parameters in CPLEX](https://discourse.julialang.org/t/defining-parameters-in-cplex/34476)

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**Author:** [@angeloaliano1](https://discourse.julialang.org/u/angeloaliano1)\
**Replies:** 3\
**Last updated:** [February 11, 2020, 6:51pm UTC](https://discourse.julialang.org/t/defining-parameters-in-cplex/34476 "2020-02-11T18:51:42Z")

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Hello dears users, I want to define the limit of CPU time, gap etc for CPLEX in a given integer problem. In JuMP version v0.19 I was used to define: model=Model(with\_optimizer(CPLEX.Optimizer,CPX\_PARAM\_TILIM=10800,CPX\_…

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## [Revise.jl with Parameters.jl erroneous "invalid redefinition of constant" in 1.3.1](https://discourse.julialang.org/t/revise-jl-with-parameters-jl-erroneous-invalid-redefinition-of-constant-in-1-3-1/34475)

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**Author:** [@torgo](https://discourse.julialang.org/u/torgo)\
**Replies:** 3\
**Last updated:** [February 11, 2020, 6:07pm UTC](https://discourse.julialang.org/t/revise-jl-with-parameters-jl-erroneous-invalid-redefinition-of-constant-in-1-3-1/34475 "2020-02-11T18:07:56Z")

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Here is a file called ReviseBehavior.jl module ReviseBehavior using Parameters @with\_kw struct MyStruct x::Array{\<:Real, 1} = \[.05\] end export MyStruct function foo() print("hello") end export foo end Here …

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## [Vscode visual debugging extension](https://discourse.julialang.org/t/vscode-visual-debugging-extension/34468)

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**Author:** [@affans](https://discourse.julialang.org/u/affans)\
**Replies:** 1\
**Last updated:** [February 11, 2020, 5:13pm UTC](https://discourse.julialang.org/t/vscode-visual-debugging-extension/34468 "2020-02-11T17:13:47Z")

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I came across this extension and was wondering if it’s possible to implement this in the Julia vc code extension. I believe Julia exposes AST in a simple manner, and so if it matches one of the interfaces the visual exte…

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## [Help understanding CompatHelper error](https://discourse.julialang.org/t/help-understanding-compathelper-error/34369)

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**Author:** [@essenciary](https://discourse.julialang.org/u/essenciary)\
**Replies:** 7\
**Last updated:** [February 11, 2020, 4:01pm UTC](https://discourse.julialang.org/t/help-understanding-compathelper-error/34369 "2020-02-11T16:01:39Z")

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A couple of days ago I begun getting errors from the CompatHelper Github action. For the life of me I can’t figure out how to fix it. Example of a failing job here: https://github.com/GenieFramework/Genie.jl/commit/c61…

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## [Does inlining work when the function is passed as an argument?](https://discourse.julialang.org/t/does-inlining-work-when-the-function-is-passed-as-an-argument/34470)

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**Author:** [@HenriDeh](https://discourse.julialang.org/u/HenriDeh)\
**Replies:** 2\
**Last updated:** [February 11, 2020, 3:55pm UTC](https://discourse.julialang.org/t/does-inlining-work-when-the-function-is-passed-as-an-argument/34470 "2020-02-11T15:55:40Z")

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Just wondering. For example @inline function foo(x,y) @assert length(x) == length(y) x .+ y.\*rand(length(y)) end function apply\_function(x,y,f) f(x,y) end julia\> apply\_function(rand(10), rand(10), foo)

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## [Draw text on Gtk canvas](https://discourse.julialang.org/t/draw-text-on-gtk-canvas/34462)

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**Author:** [@Christopher\_Fisher](https://discourse.julialang.org/u/Christopher_Fisher)\
**Replies:** 4\
**Last updated:** [February 11, 2020, 3:19pm UTC](https://discourse.julialang.org/t/draw-text-on-gtk-canvas/34462 "2020-02-11T15:19:36Z")

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I am trying to draw letters of a specific size, color, opacity, and location in a Gtk window. Here is an example of what the output might look like: example. I am able to draw rectangles with the following code: functi…

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## [Obtaining Gap in integer programming](https://discourse.julialang.org/t/obtaining-gap-in-integer-programming/34377)

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**Author:** [@angeloaliano1](https://discourse.julialang.org/u/angeloaliano1)\
**Replies:** 9\
**Last updated:** [February 11, 2020, 2:58pm UTC](https://discourse.julialang.org/t/obtaining-gap-in-integer-programming/34377 "2020-02-11T14:58:30Z")

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Hello dear, I have an interest to obtain the relative Gap in a optimization integer problem. I have consulted Reference · MathOptInterface and when I give the command RelativeGap(), nothing happens. The CPLEX and Juli…

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## [Problem evaluating symbol for macro inside function](https://discourse.julialang.org/t/problem-evaluating-symbol-for-macro-inside-function/30142)

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**Author:** [@iloaiza](https://discourse.julialang.org/u/iloaiza)\
**Replies:** 4\
**Last updated:** [February 11, 2020, 2:37pm UTC](https://discourse.julialang.org/t/problem-evaluating-symbol-for-macro-inside-function/30142 "2020-02-11T14:37:18Z")

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Hey! I have been trying to make a saving macro to simplify my life and skip having to do the full saving syntax while keeping track of what I’m saving where. To do this, I have started writing a module. The main macro is…

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## [Unitful arguments to functions?](https://discourse.julialang.org/t/unitful-arguments-to-functions/34382)

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**Author:** [@angelv](https://discourse.julialang.org/u/angelv)\
**Replies:** 6\
**Last updated:** [February 11, 2020, 2:03pm UTC](https://discourse.julialang.org/t/unitful-arguments-to-functions/34382 "2020-02-11T14:03:53Z")

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Hi, just started using Unitful.jl, and it looks great. I wanted to define a function that takes, as a first argument, some length, and as second argument something inverse length. First one is no problem, but despite tr…

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## [Failed to Precompile Plots due to LoadError](https://discourse.julialang.org/t/failed-to-precompile-plots-due-to-loaderror/34450)

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**Author:** [@Daniel\_Cardoso](https://discourse.julialang.org/u/Daniel_Cardoso)\
**Replies:** 4\
**Last updated:** [February 11, 2020, 1:47pm UTC](https://discourse.julialang.org/t/failed-to-precompile-plots-due-to-loaderror/34450 "2020-02-11T13:47:18Z")

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Every time I try to use the Plots package( simply by writing “using Plots”) it gives me this error: ┌ Info: Precompiling Plots \[91a5bcdd-55d7-5caf-9e0b-520d859cae80\] └ @ Base loading.jl:1273 ERROR: LoadError: syntax: …

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## [Senior ML Engineering at Beacon Biosignals](https://discourse.julialang.org/t/senior-ml-engineering-at-beacon-biosignals/34466)

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**Author:** [@jrevels](https://discourse.julialang.org/u/jrevels)\
**Replies:** 0\
**Last updated:** [February 11, 2020, 12:28pm UTC](https://discourse.julialang.org/t/senior-ml-engineering-at-beacon-biosignals/34466 "2020-02-11T12:28:09Z")

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Beacon Biosignals is seeking talented ML engineers to help flesh out the fundamental deep learning models that drive our platform for rapid analysis, sleek visualization, and interactive exploration of biosignal data! F…

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## [Second order differential equation blows up numerically, and I have no clue why. Any ideas?](https://discourse.julialang.org/t/second-order-differential-equation-blows-up-numerically-and-i-have-no-clue-why-any-ideas/34427)

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**Author:** [@rmz](https://discourse.julialang.org/u/rmz)\
**Replies:** 11\
**Last updated:** [February 11, 2020, 12:22pm UTC](https://discourse.julialang.org/t/second-order-differential-equation-blows-up-numerically-and-i-have-no-clue-why-any-ideas/34427 "2020-02-11T12:22:35Z")

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Hi I’m still in the newbie category so I dare ask this question as a “First Steps” question. I read this blog: https://www.johndcook.com/blog/2020/02/08/arenstorf-orbit/ … about an equation that was used to constr…

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## [Difference between deepcopy() and deepcopy.() ? Do I have to broadcast deepcopy over lists?](https://discourse.julialang.org/t/difference-between-deepcopy-and-deepcopy-do-i-have-to-broadcast-deepcopy-over-lists/34460)

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**Author:** [@Volker](https://discourse.julialang.org/u/Volker)\
**Replies:** 3\
**Last updated:** [February 11, 2020, 10:55am UTC](https://discourse.julialang.org/t/difference-between-deepcopy-and-deepcopy-do-i-have-to-broadcast-deepcopy-over-lists/34460 "2020-02-11T10:55:49Z")

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I have seen a behaviour that confused me a little bit. I have a list with structs (list\_of\_structs) and I selected specific indices of it with an integer array (idx\_array). When I then manipulate structs of the list\_of\_s…

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## [Question about \`PackageCompiler.create\_sysimage\` parameters](https://discourse.julialang.org/t/question-about-packagecompiler-create-sysimage-parameters/34447)

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**Author:** [@xiaodai](https://discourse.julialang.org/u/xiaodai)\
**Replies:** 4\
**Last updated:** [February 11, 2020, 9:39am UTC](https://discourse.julialang.org/t/question-about-packagecompiler-create-sysimage-parameters/34447 "2020-02-11T09:39:08Z")

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In particular, I want to understand what’s the difference between precompile\_execution\_file::Union{String, Vector{String}}: A file or list of files that contain code which precompilation statements should be reco…

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## [Add composition operator ⨟ Unicode 2A1F for flipped ∘](https://discourse.julialang.org/t/add-composition-operator-unicode-2a1f-for-flipped/34436)

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**Author:** [@schlichtanders](https://discourse.julialang.org/u/schlichtanders)\
**Replies:** 10\
**Last updated:** [February 11, 2020, 8:16am UTC](https://discourse.julialang.org/t/add-composition-operator-unicode-2a1f-for-flipped/34436 "2020-02-11T08:16:08Z")

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Dear Julia designers, having read parts of the Applied Category Book Seven Sketches of Compositionality by Brendan Fong and David I. Spivak I really appreciate the use of the \\fatsemi operator ⨟ It is just the reversed…

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## [How would I convert the key value pairs of an accumulator data structure to a dataframe](https://discourse.julialang.org/t/how-would-i-convert-the-key-value-pairs-of-an-accumulator-data-structure-to-a-dataframe/34438)

<div class="topic-metadata">

**Author:** [@Julia1](https://discourse.julialang.org/u/Julia1)\
**Replies:** 1\
**Last updated:** [February 11, 2020, 7:58am UTC](https://discourse.julialang.org/t/how-would-i-convert-the-key-value-pairs-of-an-accumulator-data-structure-to-a-dataframe/34438 "2020-02-11T07:58:32Z")

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Hi, I’m using the count function from the accumulator data structure from DataStructures.jl, and I’m getting exactly what I need, but I’m having a tough time extracting the values. I went to the source code and there ar…

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## [Trouble with IJulia after upgrade to 1.3.1](https://discourse.julialang.org/t/trouble-with-ijulia-after-upgrade-to-1-3-1/34412)

<div class="topic-metadata">

**Author:** [@leiteiro](https://discourse.julialang.org/u/leiteiro)\
**Replies:** 8\
**Last updated:** [February 11, 2020, 6:40am UTC](https://discourse.julialang.org/t/trouble-with-ijulia-after-upgrade-to-1-3-1/34412 "2020-02-11T06:40:56Z")

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After switching to Julia 1.3.1 IJulia does not work any more on my system. In the output below you can see what happened. The installation of Jupyter went well. But the call notebook() shows some info about the environm…

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