# General Usage

**URL:** https://discourse.julialang.org/c/usage/6.md?page=571

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

**Page:** 572

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## [Colours in logs](https://discourse.julialang.org/t/colours-in-logs/65181)

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**Author:** [@tlienart](https://discourse.julialang.org/u/tlienart)\
**Replies:** 2\
**Last updated:** [July 23, 2021, 3:11pm UTC](https://discourse.julialang.org/t/colours-in-logs/65181 "2021-07-23T15:11:25Z")

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Is there a way to colour part of a string in e.g. @info? similar to what Crayons or printstyled does. I’d like to do something like: information = "some info" @info "A string with $(highlight(information))" thanks in…

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## [Elegant way to implement a rotating convolution filter without using \`rot90\` etc](https://discourse.julialang.org/t/elegant-way-to-implement-a-rotating-convolution-filter-without-using-rot90-etc/65180)

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**Author:** [@xiaodai](https://discourse.julialang.org/u/xiaodai)\
**Replies:** 0\
**Last updated:** [July 23, 2021, 1:46pm UTC](https://discourse.julialang.org/t/elegant-way-to-implement-a-rotating-convolution-filter-without-using-rot90-etc/65180 "2021-07-23T13:46:34Z")

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I am looking to implement a simple rotational convolutional filter to be used with Flux.jl see post describing the filter deep learning - Does a rotational convolutional filter exist in neural networks? - Data Science St…

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## [Include() works, includet() doesn't in CodeOSS sesson](https://discourse.julialang.org/t/include-works-includet-doesnt-in-codeoss-sesson/65171)

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**Author:** [@Henri\_Laurie](https://discourse.julialang.org/u/Henri_Laurie)\
**Replies:** 0\
**Last updated:** [July 23, 2021, 12:50pm UTC](https://discourse.julialang.org/t/include-works-includet-doesnt-in-codeoss-sesson/65171 "2021-07-23T12:50:33Z")

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Hi all — can’t tell if this similar to previously reported issues. In CodeOSS, started fresh, simple @ode\_def operation (see ParameterizedFunctions) fails with includet() call but succeeds with include() call. Here’s a …

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## [Opinions for exporting common names](https://discourse.julialang.org/t/opinions-for-exporting-common-names/64995)

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**Author:** [@DrChainsaw](https://discourse.julialang.org/u/DrChainsaw)\
**Replies:** 29\
**Last updated:** [July 23, 2021, 11:38am UTC](https://discourse.julialang.org/t/opinions-for-exporting-common-names/64995 "2021-07-23T11:38:36Z")

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As title says, what are your favourite ways to deal with functions/types which are central to the functionality of a package but for which the best name carry a high risk of collisions? Concrete examples in my case are f…

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## [Type inference: are small Unions ok?](https://discourse.julialang.org/t/type-inference-are-small-unions-ok/65155)

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**Author:** [@mzgubic](https://discourse.julialang.org/u/mzgubic)\
**Replies:** 3\
**Last updated:** [July 23, 2021, 10:52am UTC](https://discourse.julialang.org/t/type-inference-are-small-unions-ok/65155 "2021-07-23T10:52:37Z")

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I am trying to understand type inference better. My understanding is very basic: knowing the output types from the input types is good, not knowing is bad. I don’t really understand what causes the slowdown. In any case…

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## [Symbolics.jl substitute limitations](https://discourse.julialang.org/t/symbolics-jl-substitute-limitations/64953)

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**Author:** [@Allan\_Baker](https://discourse.julialang.org/u/Allan_Baker)\
**Replies:** 11\
**Last updated:** [July 23, 2021, 10:11am UTC](https://discourse.julialang.org/t/symbolics-jl-substitute-limitations/64953 "2021-07-23T10:11:35Z")

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What are the limitations on the Symbolics.substitute command. I wanted to reduce the complexity of hand-code conversions in a symbolic inverse calculation by substituting the elements from the original calculation back …

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## [Custom Subject in Rocket.jl (for mouse events from GLFW)](https://discourse.julialang.org/t/custom-subject-in-rocket-jl-for-mouse-events-from-glfw/65133)

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**Author:** [@Jakub\_Mitura](https://discourse.julialang.org/u/Jakub_Mitura)\
**Replies:** 2\
**Last updated:** [July 23, 2021, 9:57am UTC](https://discourse.julialang.org/t/custom-subject-in-rocket-jl-for-mouse-events-from-glfw/65133 "2021-07-23T09:57:35Z")

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Hello I am trying to use the Rocket.jl - reactive programming and I do not understand how to create custom Observable/Subject I have an GLFW function that gives back information when user use scroll and in this case pr…

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## [Creating CLI tools in Julia](https://discourse.julialang.org/t/creating-cli-tools-in-julia/65012)

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**Author:** [@satyabrata\_pal](https://discourse.julialang.org/u/satyabrata_pal)\
**Replies:** 6\
**Last updated:** [July 23, 2021, 8:49am UTC](https://discourse.julialang.org/t/creating-cli-tools-in-julia/65012 "2021-07-23T08:49:35Z")

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Hello everyone. I am trying to build CLI tool for my project. Is there any existing library/package in the Julia ecosystem which I can use.

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## [PyJulia multithreading segfaults](https://discourse.julialang.org/t/pyjulia-multithreading-segfaults/65111)

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**Author:** [@andrewkhardy](https://discourse.julialang.org/u/andrewkhardy)\
**Replies:** 1\
**Last updated:** [July 23, 2021, 8:28am UTC](https://discourse.julialang.org/t/pyjulia-multithreading-segfaults/65111 "2021-07-23T08:28:30Z")

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I am wondering if the Julia community has any suggestions for importing code from Julia to Python in some manner other than the PyJulia package or suggestions on how to properly use that package as the GitHub seems to be…

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## [Is BinaryBuilder supposed to work on Windows?](https://discourse.julialang.org/t/is-binarybuilder-supposed-to-work-on-windows/65145)

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**Author:** [@joa-quim](https://discourse.julialang.org/u/joa-quim)\
**Replies:** 5\
**Last updated:** [July 23, 2021, 8:01am UTC](https://discourse.julialang.org/t/is-binarybuilder-supposed-to-work-on-windows/65145 "2021-07-23T08:01:38Z")

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Made my first try but didn’t go very far (not to mention that it didn’t accept the source location from local disk) You have the following contents in your working directory: - imgtexture IOError: could not spawn \`do…

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## [Calling Julia from Matlab - the smoothest path to sneak Julia into a company](https://discourse.julialang.org/t/calling-julia-from-matlab-the-smoothest-path-to-sneak-julia-into-a-company/64845)

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**Author:** [@Bardo](https://discourse.julialang.org/u/Bardo)\
**Replies:** 10\
**Last updated:** [July 23, 2021, 6:41am UTC](https://discourse.julialang.org/t/calling-julia-from-matlab-the-smoothest-path-to-sneak-julia-into-a-company/64845 "2021-07-23T06:41:50Z")

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I would have loved to see such an announcement. The search on this topic is frustrating, the developments appear to have ended in 2018. I see these possible routes One like in Mex.jl and others, using a mexjulia.cpp…

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## [Making RNG's fast](https://discourse.julialang.org/t/making-rngs-fast/65129)

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**Author:** [@viraltux](https://discourse.julialang.org/u/viraltux)\
**Replies:** 4\
**Last updated:** [July 22, 2021, 9:28pm UTC](https://discourse.julialang.org/t/making-rngs-fast/65129 "2021-07-22T21:28:16Z")

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I am playing around with RNG’s, specifically this one: function squares(ctr::UInt64, key::UInt64)::UInt32 y = x = ctr \* key; z = y + key x = x\*x + y; x = (x\>\>32) | (x\<\<32) # round 1 x = x\*x + z; x = (…

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## [SIMD Complex Numbers](https://discourse.julialang.org/t/simd-complex-numbers/65038)

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**Author:** [@danny.s](https://discourse.julialang.org/u/danny.s)\
**Replies:** 19\
**Last updated:** [July 22, 2021, 9:24pm UTC](https://discourse.julialang.org/t/simd-complex-numbers/65038 "2021-07-22T21:24:16Z")

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Hi, I hope this hasn’t been discussed before, but has SIMD support for complex numbers been considered? There are several libraries in C/C++ taking advantage of this. There’s an example of implementation here and vector…

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## [Should I use HDF5 to speed up reading image data repeatedly?](https://discourse.julialang.org/t/should-i-use-hdf5-to-speed-up-reading-image-data-repeatedly/57576)

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**Author:** [@kimlaberinto](https://discourse.julialang.org/u/kimlaberinto)\
**Replies:** 12\
**Last updated:** [July 22, 2021, 6:45pm UTC](https://discourse.julialang.org/t/should-i-use-hdf5-to-speed-up-reading-image-data-repeatedly/57576 "2021-07-22T18:45:46Z")

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Hi all, I’m trying to speed-up the following piece of code for an art project. I have a collection of png images. All of them together is 25GB+ And in a loop, I need to keep copying an arbitrary pixel in one of the pn…

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## [Operations with time duration](https://discourse.julialang.org/t/operations-with-time-duration/64983)

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**Author:** [@julio.ca2020](https://discourse.julialang.org/u/julio.ca2020)\
**Replies:** 20\
**Last updated:** [July 22, 2021, 4:43pm UTC](https://discourse.julialang.org/t/operations-with-time-duration/64983 "2021-07-22T16:43:11Z")

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I am relatively new to Julia. I don’t see a way to do the following in Julia in an easy way, like en excel… t = 1h5m2s average per Km = t/5 = 13m0s400ms Any help?

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## [IJulia & PyCall: output buffering](https://discourse.julialang.org/t/ijulia-pycall-output-buffering/26438)

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**Author:** [@aplavin](https://discourse.julialang.org/u/aplavin)\
**Replies:** 12\
**Last updated:** [July 22, 2021, 4:50pm UTC](https://discourse.julialang.org/t/ijulia-pycall-output-buffering/26438 "2021-07-22T16:50:18Z")

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I noticed that all output from PyCall is buffered in IJulia till the cell finishes evaluating, which is often extremely inconvenient: one cannot easily track progress of a python computation, if it uses stdout for that. …

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## [Imrotate won't fill when called](https://discourse.julialang.org/t/imrotate-wont-fill-when-called/64630)

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**Author:** [@JAgho](https://discourse.julialang.org/u/JAgho)\
**Replies:** 2\
**Last updated:** [July 22, 2021, 3:20pm UTC](https://discourse.julialang.org/t/imrotate-wont-fill-when-called/64630 "2021-07-22T15:20:50Z")

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I’m trying to use imrotate with control of fill values from ImageTransformations.jl. This has a couple of prerequisites for use, namely Interpolations.jl to permit filling of values other than NaN using Images using Int…

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## [Calculations in type parameters without pure](https://discourse.julialang.org/t/calculations-in-type-parameters-without-pure/65106)

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**Author:** [@Tamas\_Papp](https://discourse.julialang.org/u/Tamas_Papp)\
**Replies:** 3\
**Last updated:** [July 22, 2021, 3:15pm UTC](https://discourse.julialang.org/t/calculations-in-type-parameters-without-pure/65106 "2021-07-22T15:15:30Z")

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Suppose I have a type parameter M, which is a deterministic function of another parameter N. I would like to save it in the type, but not sure how to make this type stable without @pure. Is that even possible? MWE: @inl…

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## [Relocatable app workflow with PackageCompiler](https://discourse.julialang.org/t/relocatable-app-workflow-with-packagecompiler/65058)

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**Author:** [@connormeaton](https://discourse.julialang.org/u/connormeaton)\
**Replies:** 5\
**Last updated:** [July 22, 2021, 2:43pm UTC](https://discourse.julialang.org/t/relocatable-app-workflow-with-packagecompiler/65058 "2021-07-22T14:43:15Z")

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Thanks to the help of @oheil, @mkitti, and @kristoffer.carlsson, I have compiled a julia app using PackageCompiler and PkgTemplate that accepts a file path as a command line argument and prints it out as a dataframe. He…

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## [Optim.jl can't optimize function which includes BigFloat variables](https://discourse.julialang.org/t/optim-jl-cant-optimize-function-which-includes-bigfloat-variables/65095)

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**Author:** [@Strange\_Xue](https://discourse.julialang.org/u/Strange_Xue)\
**Replies:** 6\
**Last updated:** [July 22, 2021, 1:12pm UTC](https://discourse.julialang.org/t/optim-jl-cant-optimize-function-which-includes-bigfloat-variables/65095 "2021-07-22T13:12:06Z")

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This is a simple maximum likelihood estimation example from the tutorials of the Optm.jl, I just change the the log\_ \\sigma 's type from float to BigFloat in the Log\_Likelihood function , however, the error message show…

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## [Comparing Julia and Python for basic operations](https://discourse.julialang.org/t/comparing-julia-and-python-for-basic-operations/65087)

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**Author:** [@daviddoij](https://discourse.julialang.org/u/daviddoij)\
**Replies:** 8\
**Last updated:** [July 22, 2021, 12:50pm UTC](https://discourse.julialang.org/t/comparing-julia-and-python-for-basic-operations/65087 "2021-07-22T12:50:33Z")

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Hi there Julia community!, I’m quite new to the language and I’m falling in love more and more with it every day :slight\_smile: In order to improve my knowledge, I’m revisiting Project Euler problems, which I’ve done i…

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## [Failed to install Plots.jl LoadError on Arch Linux](https://discourse.julialang.org/t/failed-to-install-plots-jl-loaderror-on-arch-linux/65019)

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**Author:** [@oponkork](https://discourse.julialang.org/u/oponkork)\
**Replies:** 8\
**Last updated:** [July 22, 2021, 8:40am UTC](https://discourse.julialang.org/t/failed-to-install-plots-jl-loaderror-on-arch-linux/65019 "2021-07-22T08:40:46Z")

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I am unable to install Plots.jl on Arch Linux with julia version 1.6.2. Output of \]status Status \`~/.julia/environments/v1.6/Project.toml\` \[0c46a032\] DifferentialEquations v6.17.2 \[634d3b9d\] DrWatson v2.1.0 …

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## [LoopVectorization.jl vmap gives an error ::VectorizationBase.Vec{4, Int64}](https://discourse.julialang.org/t/loopvectorization-jl-vmap-gives-an-error-vectorizationbase-vec-4-int64/65056)

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**Author:** [@Storopoli](https://discourse.julialang.org/u/Storopoli)\
**Replies:** 17\
**Last updated:** [July 22, 2021, 8:12am UTC](https://discourse.julialang.org/t/loopvectorization-jl-vmap-gives-an-error-vectorizationbase-vec-4-int64/65056 "2021-07-22T08:12:57Z")

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I am trying to do a vmap on a function. map and ThreadsX.map both work. collatz(x::Int64) = if iseven(x) x ÷ 2 else 3x + 1 end function collatz\_sequencia(x::Int64) n = 0 while true …

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## [Substituting elements of array is very slow](https://discourse.julialang.org/t/substituting-elements-of-array-is-very-slow/65036)

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**Author:** [@mscheffel](https://discourse.julialang.org/u/mscheffel)\
**Replies:** 23\
**Last updated:** [July 22, 2021, 7:35am UTC](https://discourse.julialang.org/t/substituting-elements-of-array-is-very-slow/65036 "2021-07-22T07:35:40Z")

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I am new to Julia and I have problems with the speed. What is the fastest way to replace rows in an array? Currently I iterate over any entry of a matrix and when the result of the associated calculation is nonzero, I st…

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## [How open tutorials in jupyter from github.com/SciML/SciMLTutorials.jl?](https://discourse.julialang.org/t/how-open-tutorials-in-jupyter-from-github-com-sciml-scimltutorials-jl/64877)

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**Author:** [@murrayE](https://discourse.julialang.org/u/murrayE)\
**Replies:** 8\
**Last updated:** [July 22, 2021, 7:07am UTC](https://discourse.julialang.org/t/how-open-tutorials-in-jupyter-from-github-com-sciml-scimltutorials-jl/64877 "2021-07-22T07:07:52Z")

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In the REPL, I added https://github.com/SciML/SciMLTutorials.jl. Next, I started conda and in the conda base started the jupyter server. According to the docs for SciMLTutorials.jl, one is supposed to open the provided …

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## [GridapGmsh "GmshDiscreteModel" load error](https://discourse.julialang.org/t/gridapgmsh-gmshdiscretemodel-load-error/65084)

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**Author:** [@Cyber](https://discourse.julialang.org/u/Cyber)\
**Replies:** 2\
**Last updated:** [July 22, 2021, 6:24am UTC](https://discourse.julialang.org/t/gridapgmsh-gmshdiscretemodel-load-error/65084 "2021-07-22T06:24:45Z")

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Hello all, I encountered some problems when I would like to follow the Gridap tutorials to create a json file. I have generated a msh file from Gmsh by clicking save\_mesh button in it. And I exactly copy the right path…

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## [R in Julia, what is the best package?](https://discourse.julialang.org/t/r-in-julia-what-is-the-best-package/65076)

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**Author:** [@maoc](https://discourse.julialang.org/u/maoc)\
**Replies:** 4\
**Last updated:** [July 22, 2021, 12:40am UTC](https://discourse.julialang.org/t/r-in-julia-what-is-the-best-package/65076 "2021-07-22T00:40:07Z")

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What is the best way to introduce the R language in Julia? I looked for some alternatives and found a package called RCall.jl Are there any other options (maybe better) than this package?

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## [Performance of abstract argument in methods](https://discourse.julialang.org/t/performance-of-abstract-argument-in-methods/65066)

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**Author:** [@filchristou](https://discourse.julialang.org/u/filchristou)\
**Replies:** 2\
**Last updated:** [July 21, 2021, 9:50pm UTC](https://discourse.julialang.org/t/performance-of-abstract-argument-in-methods/65066 "2021-07-21T21:50:20Z")

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It occurs to me, maybe mistakenly, that there is a tendency to believe that being precise with your type arguments in functions also gives you performant code. Performance Tips doesn’t explicitly mention something like t…

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## [Git pull - merge conflicts with Manifest.toml although it's in .gitignore](https://discourse.julialang.org/t/git-pull-merge-conflicts-with-manifest-toml-although-its-in-gitignore/65069)

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**Author:** [@meck](https://discourse.julialang.org/u/meck)\
**Replies:** 0\
**Last updated:** [July 21, 2021, 8:52pm UTC](https://discourse.julialang.org/t/git-pull-merge-conflicts-with-manifest-toml-although-its-in-gitignore/65069 "2021-07-21T20:52:34Z")

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➜ Oceananigans.jl git:(master) git pull Auto-merging Project.toml Auto-merging Manifest.toml CONFLICT (content): Merge conflict in Manifest.toml error: could not apply 501c1db7... updates in manifest and project tomls R…

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## [Skipping a whole \`@testset\`?](https://discourse.julialang.org/t/skipping-a-whole-testset/65006)

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**Author:** [@johnomotani](https://discourse.julialang.org/u/johnomotani)\
**Replies:** 3\
**Last updated:** [July 21, 2021, 7:21pm UTC](https://discourse.julialang.org/t/skipping-a-whole-testset/65006 "2021-07-21T19:21:26Z")

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I have a bunch of similar @testsets, and I know that some of them currently fail, and will do so until some upgrades are made to my package. For skipping single tests, there’s @test\_skip or @test\_broken, but is there a n…

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