# Latest

**URL:** https://discourse.julialang.org/latest.md?page=1647

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

**Page:** 1648

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## [Use of 'in' or function in array](https://discourse.julialang.org/t/use-of-in-or-function-in-array/45636)

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**Author:** [@jobdiogenes](https://discourse.julialang.org/u/jobdiogenes)\
**Replies:** 2\
**Last updated:** [August 27, 2020, 6:00pm UTC](https://discourse.julialang.org/t/use-of-in-or-function-in-array/45636 "2020-08-27T18:00:46Z")

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Example array: C = \[1 2 3 5;4 5 6 8;7 8 9 0; 3 6 9 12\] 4×4 Array{Int64,2}: 1 2 3 5 4 5 6 8 7 8 9 0 3 6 9 1 I could strip out cols, or rows by C\[1:end .!=2,1:end .!=3\] 3×3 Array{Int64,2}: 1 2 5…

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## [CartesianIndex() - how to? - general questions](https://discourse.julialang.org/t/cartesianindex-how-to-general-questions/45630)

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**Author:** [@neo\_abs](https://discourse.julialang.org/u/neo_abs)\
**Replies:** 5\
**Last updated:** [August 27, 2020, 5:37pm UTC](https://discourse.julialang.org/t/cartesianindex-how-to-general-questions/45630 "2020-08-27T17:37:20Z")

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Is there a convenient way to: Convert CaresianIndex into Vector{\<:Integer} Convert CartesianIndex{4} into CartesianIndex{3} by removing last coordinate? get k first values of Cartesian Index ( CI\[1:4\] → returns Cartes…

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## [Computing pairwise Sørensen–Dice coefficient between many BitVectors](https://discourse.julialang.org/t/computing-pairwise-sorensen-dice-coefficient-between-many-bitvectors/45567)

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**Author:** [@Brian\_Thorne](https://discourse.julialang.org/u/Brian_Thorne)\
**Replies:** 4\
**Last updated:** [August 27, 2020, 3:33pm UTC](https://discourse.julialang.org/t/computing-pairwise-sorensen-dice-coefficient-between-many-bitvectors/45567 "2020-08-27T15:33:58Z")

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Hi all, I’m trying to match (or ideally beat) the performance of a Python/C library (anonlink) that computes the Sørensen–Dice coefficient but I’m struggling to match the performance - except when calling the same C code…

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## [Using @sprintf inside a macro](https://discourse.julialang.org/t/using-sprintf-inside-a-macro/45275)

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**Author:** [@anj](https://discourse.julialang.org/u/anj)\
**Replies:** 31\
**Last updated:** [August 27, 2020, 3:11pm UTC](https://discourse.julialang.org/t/using-sprintf-inside-a-macro/45275 "2020-08-27T15:11:47Z")

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I need to prefix my log lines with a timestamp. so I was thinking overloading @printf along those lines import Printf.@printf macro printf(args...) tmp\_str = @sprintf(args...) return :(print(now(), " : ", tmp\_s…

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## [A minor group-by benchmark - DataFrames.jl plenty fast](https://discourse.julialang.org/t/a-minor-group-by-benchmark-dataframes-jl-plenty-fast/45622)

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**Author:** [@xiaodai](https://discourse.julialang.org/u/xiaodai)\
**Replies:** 5\
**Last updated:** [August 27, 2020, 3:00pm UTC](https://discourse.julialang.org/t/a-minor-group-by-benchmark-dataframes-jl-plenty-fast/45622 "2020-08-27T15:00:39Z")

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I once made a FastGroupBy.jl to do some fast group by but now DataFrames.jl is plenty fast by itself! DataFrames.jl has done lots of optimizations, I wonder what’s been done. Database-like ops benchmark is showing real…

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## [Cygdrive/StackOverflowError() error - any ideas how to fix this?](https://discourse.julialang.org/t/cygdrive-stackoverflowerror-error-any-ideas-how-to-fix-this/45589)

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**Author:** [@cbasile21](https://discourse.julialang.org/u/cbasile21)\
**Replies:** 0\
**Last updated:** [August 26, 2020, 7:11pm UTC](https://discourse.julialang.org/t/cygdrive-stackoverflowerror-error-any-ideas-how-to-fix-this/45589 "2020-08-26T19:11:30Z")

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Hi All, every time I run any code ever since I started using version 1.4 the following pops up, any ideas of how to fix it. I am thinking of jumping to version 1.5 , (Now I am using version 1.5.1) again thank you! Some…

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## [Bug or feature: nested let variable scope](https://discourse.julialang.org/t/bug-or-feature-nested-let-variable-scope/45613)

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**Author:** [@systems](https://discourse.julialang.org/u/systems)\
**Replies:** 4\
**Last updated:** [August 27, 2020, 2:38pm UTC](https://discourse.julialang.org/t/bug-or-feature-nested-let-variable-scope/45613 "2020-08-27T14:38:04Z")

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I was expecting the second and third code to behave exactly like first, except neither behave the same # First i = 0 let i = 1 Fs = Vector{Any}(undef, 2) while i \<= 2 let j = i …

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## [Package does not meet sequential version number guideline](https://discourse.julialang.org/t/package-does-not-meet-sequential-version-number-guideline/44752)

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**Author:** [@lmiq](https://discourse.julialang.org/u/lmiq)\
**Replies:** 16\
**Last updated:** [August 27, 2020, 1:29pm UTC](https://discourse.julialang.org/t/package-does-not-meet-sequential-version-number-guideline/44752 "2020-08-27T13:29:40Z")

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I keep getting these messages when registering new versions of my package. But I do not see how I am not following the guideline, I released a patch and changed the version from 0.2.0 to 0.2.1 and after fixing another mi…

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## [Calculating principal curvatures of point clouds](https://discourse.julialang.org/t/calculating-principal-curvatures-of-point-clouds/45621)

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**Author:** [@Roy\_Toren](https://discourse.julialang.org/u/Roy_Toren)\
**Replies:** 0\
**Last updated:** [August 27, 2020, 12:24pm UTC](https://discourse.julialang.org/t/calculating-principal-curvatures-of-point-clouds/45621 "2020-08-27T12:24:33Z")

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Hello everyone, I am trying to calculate the surface variance of 3D objects. I searched for implementations of such calculations in Julia but failed to find appropriate libraries. Do you know of any libraries which im…

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## [Monochrome theme](https://discourse.julialang.org/t/monochrome-theme/45617)

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**Author:** [@yordiak](https://discourse.julialang.org/u/yordiak)\
**Replies:** 5\
**Last updated:** [August 27, 2020, 12:00pm UTC](https://discourse.julialang.org/t/monochrome-theme/45617 "2020-08-27T12:00:53Z")

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For publication purposes, I am interested to create a monochrome plots. In particular, how could I implement a monochrome theme in Plots (or in any other package) , similar to the Monochrome theme of Mathematica?

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## [Is there a way to distribute an array to different argument positions in a function?](https://discourse.julialang.org/t/is-there-a-way-to-distribute-an-array-to-different-argument-positions-in-a-function/45616)

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**Author:** [@sujunyan](https://discourse.julialang.org/u/sujunyan)\
**Replies:** 2\
**Last updated:** [August 27, 2020, 11:18am UTC](https://discourse.julialang.org/t/is-there-a-way-to-distribute-an-array-to-different-argument-positions-in-a-function/45616 "2020-08-27T11:18:22Z")

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Specifically I am seeking something like the following in python: def foo(x,y): return x+y a = \[1,2\] foo(\*a)

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## [Output in loops (Pluto.jl)](https://discourse.julialang.org/t/output-in-loops-pluto-jl/45597)

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**Author:** [@joergbuchwald](https://discourse.julialang.org/u/joergbuchwald)\
**Replies:** 1\
**Last updated:** [August 27, 2020, 10:50am UTC](https://discourse.julialang.org/t/output-in-loops-pluto-jl/45597 "2020-08-27T10:50:34Z")

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Hi! Is there an elegant way for printing output in loops in pluto notebooks, i.e., something like for i in 1:3 md"test: $(i)" end without concatenating the multiline string and output it afterward?

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## [Is it possible in Julia?: Support a limited type inference version in order to decide whether a function is defined or not](https://discourse.julialang.org/t/is-it-possible-in-julia-support-a-limited-type-inference-version-in-order-to-decide-whether-a-function-is-defined-or-not/45509)

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**Author:** [@schlichtanders](https://discourse.julialang.org/u/schlichtanders)\
**Replies:** 20\
**Last updated:** [August 27, 2020, 8:33am UTC](https://discourse.julialang.org/t/is-it-possible-in-julia-support-a-limited-type-inference-version-in-order-to-decide-whether-a-function-is-defined-or-not/45509 "2020-08-27T08:33:28Z")

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I think it would be a super helpful addition to the julia ecosystem if we could check whether some function is defined for certain arguments or not. To be precise, I don’t refer to applicable or hasmethod. They only che…

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## [Querying JuMP solutions - results out of order](https://discourse.julialang.org/t/querying-jump-solutions-results-out-of-order/45301)

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**Author:** [@fnbillimoria](https://discourse.julialang.org/u/fnbillimoria)\
**Replies:** 2\
**Last updated:** [August 27, 2020, 7:06am UTC](https://discourse.julialang.org/t/querying-jump-solutions-results-out-of-order/45301 "2020-08-27T07:06:06Z")

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Hello, I have created a JuMP model, and wish to source and sort the results. The JuMP model is created via a call to a function with results stored as below. I wish to obtain results for a variable array called pg. Ho…

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## [Question about call the Pkg in python](https://discourse.julialang.org/t/question-about-call-the-pkg-in-python/45602)

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**Author:** [@abcde](https://discourse.julialang.org/u/abcde)\
**Replies:** 0\
**Last updated:** [August 27, 2020, 2:17am UTC](https://discourse.julialang.org/t/question-about-call-the-pkg-in-python/45602 "2020-08-27T02:17:28Z")

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my code: using PyCall, Conda root = Conda.ROOTENV pipPath = joinpath(root, "bin", "pip") \`$(pipPath) install KMeans\_elbow\` Conda.add("KMeans\_elbow") KM=pyimport("KMeans\_elbow") the error: ERROR: LoadError: failed proc…

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## [Stop running code pasted into REPL on first error](https://discourse.julialang.org/t/stop-running-code-pasted-into-repl-on-first-error/44637)

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**Author:** [@fredcallaway](https://discourse.julialang.org/u/fredcallaway)\
**Replies:** 20\
**Last updated:** [August 27, 2020, 1:11am UTC](https://discourse.julialang.org/t/stop-running-code-pasted-into-repl-on-first-error/44637 "2020-08-27T01:11:02Z")

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Hi there, first time poster so not sure if this is the appropriate venue for this. My workflow involves writing code in a text editor and pasting it into a terminal (I use the Terminus and SendCode plugins in Sublime Te…

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## [Interpolations WeightedIndex trouble](https://discourse.julialang.org/t/interpolations-weightedindex-trouble/45547)

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**Author:** [@tbeason](https://discourse.julialang.org/u/tbeason)\
**Replies:** 4\
**Last updated:** [August 27, 2020, 12:47am UTC](https://discourse.julialang.org/t/interpolations-weightedindex-trouble/45547 "2020-08-27T00:47:46Z")

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Have a bit of an advanced Interpolations.jl question here… I guess I just don’t understand how to use the weightedindices or its output. Based on the docs, I assumed that I pass it the point to which I would want to int…

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## [A new classroom chat app](https://discourse.julialang.org/t/a-new-classroom-chat-app/45590)

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**Author:** [@sswatson](https://discourse.julialang.org/u/sswatson)\
**Replies:** 2\
**Last updated:** [August 26, 2020, 11:20pm UTC](https://discourse.julialang.org/t/a-new-classroom-chat-app/45590 "2020-08-26T23:20:10Z")

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I teach an applied math course in the Data Science Initiative at Brown University. I’ve been using Julia for the coding components of the course, and I’ve been very happy how that has enabled me to focus more on the math…

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## [Can we have inferable fetch(task)?](https://discourse.julialang.org/t/can-we-have-inferable-fetch-task/45541)

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**Author:** [@tkf](https://discourse.julialang.org/u/tkf)\
**Replies:** 5\
**Last updated:** [August 26, 2020, 10:47pm UTC](https://discourse.julialang.org/t/can-we-have-inferable-fetch-task/45541 "2020-08-26T22:47:38Z")

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Continuing the discussion in ANN: Parallel \`for\` loops in FLoops.jl with composable and extensible fold-based API - #18 by c42f, I wonder if we can make fetch(task) inferable using invoke\_in\_world added in Here is a q…

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## [Dynamic REPL prompt?](https://discourse.julialang.org/t/dynamic-repl-prompt/45524)

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**Author:** [@derekmahar](https://discourse.julialang.org/u/derekmahar)\
**Replies:** 10\
**Last updated:** [August 26, 2020, 9:15pm UTC](https://discourse.julialang.org/t/dynamic-repl-prompt/45524 "2020-08-26T21:15:44Z")

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How can I make the Julia REPL display a dynamic prompt? For example, how might the REPL print the current date and time in the prompt each time it prints a new prompt?

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## [Null bytes in repl\_history on shared home directory](https://discourse.julialang.org/t/null-bytes-in-repl-history-on-shared-home-directory/42471)

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**Author:** [@lhupe](https://discourse.julialang.org/u/lhupe)\
**Replies:** 3\
**Last updated:** [August 26, 2020, 7:43pm UTC](https://discourse.julialang.org/t/null-bytes-in-repl-history-on-shared-home-directory/42471 "2020-08-26T19:43:56Z")

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I’m currently using julia on a network of computers with shared home directories. I’ve noticed that when I open REPLs on two machines simultaneously, the repl\_history.jl file gets corrupted and I get this error message t…

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## [Type parameters by default?](https://discourse.julialang.org/t/type-parameters-by-default/45577)

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**Author:** [@juliohm](https://discourse.julialang.org/u/juliohm)\
**Replies:** 4\
**Last updated:** [August 26, 2020, 6:23pm UTC](https://discourse.julialang.org/t/type-parameters-by-default/45577 "2020-08-26T18:23:27Z")

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Hi everyone, I’ve noticed a pattern in my Julia code and I wondered if it would make sense to have some compiler technology to automatically add type parameters for fields that have no explicit type. For example, consi…

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## [Updating Cholesky Factorization submatrix](https://discourse.julialang.org/t/updating-cholesky-factorization-submatrix/28913)

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**Author:** [@charshaw](https://discourse.julialang.org/u/charshaw)\
**Replies:** 7\
**Last updated:** [August 26, 2020, 5:05pm UTC](https://discourse.julialang.org/t/updating-cholesky-factorization-submatrix/28913 "2020-08-26T17:05:00Z")

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I have a positive semidefinite matrix A \\in \\mathbb{R}^{n \\times n} and its Cholesky factorization is A = L L^T. I would like to update the Cholesky factorization by removing the last row and column of L. What is the co…

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## [PlotlyJS fails due to ORCA](https://discourse.julialang.org/t/plotlyjs-fails-due-to-orca/45092)

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**Author:** [@omrilesser](https://discourse.julialang.org/u/omrilesser)\
**Replies:** 12\
**Last updated:** [August 26, 2020, 4:43pm UTC](https://discourse.julialang.org/t/plotlyjs-fails-due-to-orca/45092 "2020-08-26T16:43:11Z")

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I’m trying to use Plots.jl with PlotlyJS to produce simple plots, e.g. using Plots plotlyjs() x = range(0,stop=1,length=100) y = x.^2 Plots.plot(x,y, legend=false, linecolor="red") This throws the following error due t…

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## [ModelingToolkit.jl: '===' comparison on Operations(/Expressions)](https://discourse.julialang.org/t/modelingtoolkit-jl-comparison-on-operations-expressions/45559)

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**Author:** [@NumHack](https://discourse.julialang.org/u/NumHack)\
**Replies:** 2\
**Last updated:** [August 26, 2020, 4:24pm UTC](https://discourse.julialang.org/t/modelingtoolkit-jl-comparison-on-operations-expressions/45559 "2020-08-26T16:24:10Z")

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Hi, Since this is my first post, I want to thank everyone involved in the creation of the Julia language. I would like to compare Operation/Expression objects, my initial goal being to replace sub-(Operation/Expression…

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## [Easier way to assign a variable to a row of an array?](https://discourse.julialang.org/t/easier-way-to-assign-a-variable-to-a-row-of-an-array/45545)

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**Author:** [@Jaepil\_Lee](https://discourse.julialang.org/u/Jaepil_Lee)\
**Replies:** 2\
**Last updated:** [August 26, 2020, 4:15pm UTC](https://discourse.julialang.org/t/easier-way-to-assign-a-variable-to-a-row-of-an-array/45545 "2020-08-26T16:15:28Z")

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Hello Julia users! I am trying to make a hypothetical dataset of variables X2, Z1, Z2, and ε with some mean and covariance. Using Distributions and Random packages works just fine, but I was wondering if I can assign th…

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## [Union splitting over abstract types](https://discourse.julialang.org/t/union-splitting-over-abstract-types/45568)

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**Author:** [@cstjean](https://discourse.julialang.org/u/cstjean)\
**Replies:** 5\
**Last updated:** [August 26, 2020, 2:59pm UTC](https://discourse.julialang.org/t/union-splitting-over-abstract-types/45568 "2020-08-26T14:59:18Z")

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If I have an abstract type X whose only subtypes are A and B, will union-splitting kick in and make dispatching over an object inferred as X as efficient as dispatching over one inferred as Union{A, B}?

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## [Question about PyCall](https://discourse.julialang.org/t/question-about-pycall/45565)

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**Author:** [@abcde](https://discourse.julialang.org/u/abcde)\
**Replies:** 2\
**Last updated:** [August 26, 2020, 2:15pm UTC](https://discourse.julialang.org/t/question-about-pycall/45565 "2020-08-26T14:15:59Z")

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this is my code : using PyCall, Conda pyexec = pyimport("KMeans\_elbow") this is the error: ERROR: LoadError: PyError (PyImport\_ImportModule The Python package KMeans\_elbow could not be found by pyimport. Usually this…

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## [Linting operator minus -](https://discourse.julialang.org/t/linting-operator-minus/45576)

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**Author:** [@DOT](https://discourse.julialang.org/u/DOT)\
**Replies:** 0\
**Last updated:** [August 26, 2020, 2:05pm UTC](https://discourse.julialang.org/t/linting-operator-minus/45576 "2020-08-26T14:05:46Z")

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When operator - has a type assert for the return type, the linter declares the two arguments “Missing References” (orange under-wriggle in the screenshot):

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## [Cannot use ORCA, HTTP errors](https://discourse.julialang.org/t/cannot-use-orca-http-errors/36683)

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**Author:** [@badmin](https://discourse.julialang.org/u/badmin)\
**Replies:** 7\
**Last updated:** [August 26, 2020, 1:45pm UTC](https://discourse.julialang.org/t/cannot-use-orca-http-errors/36683 "2020-08-26T13:45:03Z")

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Hi, I am having problems using ORCA today (i have it working fine on several other machines). When trying “using ORCA” i get the following: And when trying Pkg.build(“ORCA”) i get this: The HTTP errors in the …

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