# Latest

**URL:** https://discourse.julialang.org/latest.md?page=713

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

**Page:** 714

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## [Interpolation within ModelingToolkit framework](https://discourse.julialang.org/t/interpolation-within-modelingtoolkit-framework/59432)

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**Author:** [@jairorua](https://discourse.julialang.org/u/jairorua)\
**Replies:** 16\
**Last updated:** [May 1, 2023, 4:41pm UTC](https://discourse.julialang.org/t/interpolation-within-modelingtoolkit-framework/59432 "2023-05-01T16:41:51Z")

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Hello, Is there a way to interpolate within a ModelingToolkit’s (MTK) component model using the parameters/variables of the model? Interpolations.jl seems to struggle with Num types, and from the example in the document…

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## [How to efficiently differentiate backslash operator for sparse matrix?](https://discourse.julialang.org/t/how-to-efficiently-differentiate-backslash-operator-for-sparse-matrix/43778)

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**Author:** [@Liang\_Chen](https://discourse.julialang.org/u/Liang_Chen)\
**Replies:** 23\
**Last updated:** [May 1, 2023, 4:21pm UTC](https://discourse.julialang.org/t/how-to-efficiently-differentiate-backslash-operator-for-sparse-matrix/43778 "2023-05-01T16:21:24Z")

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My problem is to calculate the gradient, dL(u)/dp, where L() is a loss function which takes a vector u as the input and outputs a scalar value. The vector p are parameters that defines a large sparse matrix K, such that K…

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## [Passing DataFrameRow to transform in split-apply-combine](https://discourse.julialang.org/t/passing-dataframerow-to-transform-in-split-apply-combine/98118)

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**Author:** [@alequa](https://discourse.julialang.org/u/alequa)\
**Replies:** 4\
**Last updated:** [May 1, 2023, 4:18pm UTC](https://discourse.julialang.org/t/passing-dataframerow-to-transform-in-split-apply-combine/98118 "2023-05-01T16:18:59Z")

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Hello, I want to apply a function (my\_func) to the DataFrameRow object, so I can access all the column-names from within the function, independently of the col\_names declared in the transform. I can’t find the way of a…

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## [Error: "all-underscore identifier used as rvalue"](https://discourse.julialang.org/t/error-all-underscore-identifier-used-as-rvalue/97944)

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**Author:** [@hendri54](https://discourse.julialang.org/u/hendri54)\
**Replies:** 1\
**Last updated:** [May 1, 2023, 3:25pm UTC](https://discourse.julialang.org/t/error-all-underscore-identifier-used-as-rvalue/97944 "2023-05-01T15:25:01Z")

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I am trying to understand why the following error is thrown: julia\> function foo1(x, \_, y; z) @show x, y, z end ERROR: syntax: all-underscore identifier used as rvalue around REPL\[2\]:1 Stacktrace: \[1\] t…

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## [Failed to precompile ScikitLearn and Plots](https://discourse.julialang.org/t/failed-to-precompile-scikitlearn-and-plots/98159)

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**Author:** [@Beatha\_Shilongo](https://discourse.julialang.org/u/Beatha_Shilongo)\
**Replies:** 10\
**Last updated:** [May 1, 2023, 3:09pm UTC](https://discourse.julialang.org/t/failed-to-precompile-scikitlearn-and-plots/98159 "2023-05-01T15:09:42Z")

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Am trying to add ScikitLearn and Plots package into my Pluto note book but am getting an error. I tried updating, adding python path to Julia but did not work. Any suggestions on what I can do. error: Failed to prec…

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## [PyCall not properly installed](https://discourse.julialang.org/t/pycall-not-properly-installed/39928)

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**Author:** [@SambitMishra98](https://discourse.julialang.org/u/SambitMishra98)\
**Replies:** 6\
**Last updated:** [May 22, 2020, 7:57pm UTC](https://discourse.julialang.org/t/pycall-not-properly-installed/39928 "2020-05-22T19:57:36Z")

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I am not able to use any package which has some connection with the PyCall package. I tried following the instructions in one of the cases (for using ScikitLearn package) and have given the output below. I tried resolvin…

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## [Type-stability of recursive functions](https://discourse.julialang.org/t/type-stability-of-recursive-functions/78946)

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**Author:** [@nchisholm](https://discourse.julialang.org/u/nchisholm)\
**Replies:** 6\
**Last updated:** [May 1, 2023, 1:05pm UTC](https://discourse.julialang.org/t/type-stability-of-recursive-functions/78946 "2023-05-01T13:05:12Z")

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I have challenged myself to write a (ideally type-stable) function that computes the determinant of (small) matricies using the O(n!) recursive expansion formula without resorting to @generated. I ended up with the fol…

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## [Question on Dependency-Related Best Practice for Packages](https://discourse.julialang.org/t/question-on-dependency-related-best-practice-for-packages/98146)

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**Author:** [@TI36XPro](https://discourse.julialang.org/u/TI36XPro)\
**Replies:** 5\
**Last updated:** [May 1, 2023, 12:09pm UTC](https://discourse.julialang.org/t/question-on-dependency-related-best-practice-for-packages/98146 "2023-05-01T12:09:38Z")

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Hello, I don’t know which of the following is the better option or what should be done. I am hoping someone can help me decide. I am developing PackageA. I have PackageB currently as a dependency of PackageA. Separatel…

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## [Why almost all package be re-precompiling after a new package installed?](https://discourse.julialang.org/t/why-almost-all-package-be-re-precompiling-after-a-new-package-installed/98151)

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**Author:** [@tiZ](https://discourse.julialang.org/u/tiZ)\
**Replies:** 2\
**Last updated:** [May 1, 2023, 11:43am UTC](https://discourse.julialang.org/t/why-almost-all-package-be-re-precompiling-after-a-new-package-installed/98151 "2023-05-01T11:43:39Z")

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Hi Julia-ers, I found that adding a new package in Julia can be quite troublesome. Each time I do this, there will be also a long precompilation process that involves almost all the packages in the current project envi…

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## [Is there a Julia package similar to the Python's "ShowYourWork"?](https://discourse.julialang.org/t/is-there-a-julia-package-similar-to-the-pythons-showyourwork/97475)

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**Author:** [@martinmestre](https://discourse.julialang.org/u/martinmestre)\
**Replies:** 17\
**Last updated:** [May 1, 2023, 10:57am UTC](https://discourse.julialang.org/t/is-there-a-julia-package-similar-to-the-pythons-showyourwork/97475 "2023-05-01T10:57:02Z")

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Hello, I mean this Python package Thanks.

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## [How to fix this error when I use JUMP to maximize a function?](https://discourse.julialang.org/t/how-to-fix-this-error-when-i-use-jump-to-maximize-a-function/98155)

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**Author:** [@maoc](https://discourse.julialang.org/u/maoc)\
**Replies:** 1\
**Last updated:** [May 1, 2023, 9:53am UTC](https://discourse.julialang.org/t/how-to-fix-this-error-when-i-use-jump-to-maximize-a-function/98155 "2023-05-01T09:53:57Z")

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I’m trying to optimize a likelihood function a little different from the traditional ones. I’m going to call this likelihood function of mine “faux”. To show my problem, first see how well this example (I took this examp…

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## [OpenStreetMapX: How to efficiently convert node\_id to vertex\_id?](https://discourse.julialang.org/t/openstreetmapx-how-to-efficiently-convert-node-id-to-vertex-id/98139)

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**Author:** [@Yao\_Vang](https://discourse.julialang.org/u/Yao_Vang)\
**Replies:** 2\
**Last updated:** [May 1, 2023, 9:05am UTC](https://discourse.julialang.org/t/openstreetmapx-how-to-efficiently-convert-node-id-to-vertex-id/98139 "2023-05-01T09:05:24Z")

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Hello all When calling any routing opetion in openstreetmapX it expects node\_id and in the answer it also returns node\_id. for example: m = get\_map\_data(File\_path, use\_cache=false, trim\_to\_connected\_graph=true ); a,b =…

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## [Multi-threading of julia-1.8.5 does not improve speed when combined with BLAS](https://discourse.julialang.org/t/multi-threading-of-julia-1-8-5-does-not-improve-speed-when-combined-with-blas/97568)

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**Author:** [@therockertj](https://discourse.julialang.org/u/therockertj)\
**Replies:** 17\
**Last updated:** [May 1, 2023, 7:06am UTC](https://discourse.julialang.org/t/multi-threading-of-julia-1-8-5-does-not-improve-speed-when-combined-with-blas/97568 "2023-05-01T07:06:10Z")

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Hi, I am very new to Julia and try to use multi-threading to make my code faster. If I do not use linear algebra, my code using “Thread.@threads” for the “for” loop speeds up as expected. However, when I use linear al…

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## [Pkg.build("PyCall") errors. Need help](https://discourse.julialang.org/t/pkg-build-pycall-errors-need-help/98145)

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**Author:** [@armel3](https://discourse.julialang.org/u/armel3)\
**Replies:** 1\
**Last updated:** [May 1, 2023, 6:59am UTC](https://discourse.julialang.org/t/pkg-build-pycall-errors-need-help/98145 "2023-05-01T06:59:21Z")

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Hi, Does anyone know how I can use Pkg.build(“PyCall”) without errors in Windows? It keeps failing and I am not sure how to fix it. Any help appreciated julia\> Pkg.build("PyCall") INFO: Building Conda INFO: Building Py…

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## [Stable (tagged) versions are not being deployed?](https://discourse.julialang.org/t/stable-tagged-versions-are-not-being-deployed/98129)

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**Author:** [@tpoisot](https://discourse.julialang.org/u/tpoisot)\
**Replies:** 2\
**Last updated:** [May 1, 2023, 3:11am UTC](https://discourse.julialang.org/t/stable-tagged-versions-are-not-being-deployed/98129 "2023-05-01T03:11:24Z")

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I am using this workflow file to build the documentation for a package: The dev version works, but the tags (which are generated by TagBot) are not resulting in a stable version being built. Is there something obviou…

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## [Could not load library in Linux](https://discourse.julialang.org/t/could-not-load-library-in-linux/98130)

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**Author:** [@xialing](https://discourse.julialang.org/u/xialing)\
**Replies:** 3\
**Last updated:** [May 1, 2023, 1:38am UTC](https://discourse.julialang.org/t/could-not-load-library-in-linux/98130 "2023-05-01T01:38:18Z")

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I have tried a lot about this problem but could not find a solution. And I can’t use julia at all. Could you help me with it? Thank you a lot.

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## [Questions about testing and PkgEval, e.g. why only 63% of ecosystem tested, rest "skipped"?](https://discourse.julialang.org/t/questions-about-testing-and-pkgeval-e-g-why-only-63-of-ecosystem-tested-rest-skipped/98138)

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**Author:** [@Palli](https://discourse.julialang.org/u/Palli)\
**Replies:** 1\
**Last updated:** [May 1, 2023, 1:31am UTC](https://discourse.julialang.org/t/questions-about-testing-and-pkgeval-e-g-why-only-63-of-ecosystem-tested-rest-skipped/98138 "2023-05-01T01:31:44Z")

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In short is PkgEval/master in worse state than usual? Before people start panic, the process seems to be working as intended, except maybe the skipped packages. I’m still curious about some of the (other) failures I’m se…

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## [Trying to plot, getting no output](https://discourse.julialang.org/t/trying-to-plot-getting-no-output/98136)

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**Author:** [@jxxcarlson](https://discourse.julialang.org/u/jxxcarlson)\
**Replies:** 2\
**Last updated:** [May 1, 2023, 12:11am UTC](https://discourse.julialang.org/t/trying-to-plot-getting-no-output/98136 "2023-05-01T00:11:25Z")

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I’m running the code below (using Julia 1.8.5) but getting no output other than the below. That is, I don’t see any plot popping up. ➜ julia julia plot-sine.jl Updating registry at \`~/.julia/registries/General\` …

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## [Constructing a sum of many functions (as a new function)](https://discourse.julialang.org/t/constructing-a-sum-of-many-functions-as-a-new-function/98009)

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**Author:** [@Bill\_Holmes](https://discourse.julialang.org/u/Bill_Holmes)\
**Replies:** 15\
**Last updated:** [April 30, 2023, 9:26pm UTC](https://discourse.julialang.org/t/constructing-a-sum-of-many-functions-as-a-new-function/98009 "2023-04-30T21:26:42Z")

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Hello all. I have question about function construction. Specifically, suppose I have constructed a Vector containing a functions. That is, my vector would look like v =\[f1,f2,f3,f4,...\]. I now want to produce a new funct…

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## [Convert Dict to NamedTuple](https://discourse.julialang.org/t/convert-dict-to-namedtuple/98140)

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**Author:** [@Brinkhuis](https://discourse.julialang.org/u/Brinkhuis)\
**Replies:** 4\
**Last updated:** [April 30, 2023, 8:13pm UTC](https://discourse.julialang.org/t/convert-dict-to-namedtuple/98140 "2023-04-30T20:13:30Z")

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I’m looking for a clean way to convert Dictionaries into NamedTuples. I found a helpful topic, however, that solution only works for Dicts with symbol keys. julia\> (; Dict(:a =\> 5, :b =\> 6, :c =\> 7)…) (a = 5, b = 6, …

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## [What are different types of functions in Julia and what are the differences between them?](https://discourse.julialang.org/t/what-are-different-types-of-functions-in-julia-and-what-are-the-differences-between-them/98113)

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**Author:** [@meet.saiya](https://discourse.julialang.org/u/meet.saiya)\
**Replies:** 3\
**Last updated:** [April 30, 2023, 6:25pm UTC](https://discourse.julialang.org/t/what-are-different-types-of-functions-in-julia-and-what-are-the-differences-between-them/98113 "2023-04-30T18:25:01Z")

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I’m trying to replicate a code of Sigmoidal programming for my optimization problem. The example uses a code where they pass in a list of functions. fs = fill(logistic, nvar) dfs = fill(logistic\_prime, nvar) The output…

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## [Render Pipeline in Metal.jl](https://discourse.julialang.org/t/render-pipeline-in-metal-jl/97847)

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**Author:** [@dchang10](https://discourse.julialang.org/u/dchang10)\
**Replies:** 9\
**Last updated:** [April 30, 2023, 5:07pm UTC](https://discourse.julialang.org/t/render-pipeline-in-metal-jl/97847 "2023-04-30T17:07:49Z")

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I’m currently trying to set up a render pipeline with Metal.jl by defining a vertex shader, rasterizer and fragment shader, but am not sure how to go about it. Is there an example or description of how this is done with …

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## [Tree \<: Collection? Looking for API feedback in DynamicExpressions](https://discourse.julialang.org/t/tree-collection-looking-for-api-feedback-in-dynamicexpressions/98109)

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**Author:** [@MilesCranmer](https://discourse.julialang.org/u/MilesCranmer)\
**Replies:** 1\
**Last updated:** [April 30, 2023, 4:31pm UTC](https://discourse.julialang.org/t/tree-collection-looking-for-api-feedback-in-dynamicexpressions/98109 "2023-04-30T16:31:18Z")

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Intro I am wondering if I could others’ opinions on a potential interface for traversing expressions in DynamicExpressions.jl. To give you a sense of what the package does, the original announcement thread for this pack…

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## [Vectorization, or boundary tracing in julia](https://discourse.julialang.org/t/vectorization-or-boundary-tracing-in-julia/97638)

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**Author:** [@alex-s-gardner](https://discourse.julialang.org/u/alex-s-gardner)\
**Replies:** 10\
**Last updated:** [April 30, 2023, 4:14pm UTC](https://discourse.julialang.org/t/vectorization-or-boundary-tracing-in-julia/97638 "2023-04-30T16:14:38Z")

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Does anyone know of a julia package that can generate vectors/polygons (i,j) for the boundaries of areas found within a BitMatrix.

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## [Microsimulation with Agents?](https://discourse.julialang.org/t/microsimulation-with-agents/98119)

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**Author:** [@sbacelar](https://discourse.julialang.org/u/sbacelar)\
**Replies:** 3\
**Last updated:** [April 30, 2023, 1:10pm UTC](https://discourse.julialang.org/t/microsimulation-with-agents/98119 "2023-04-30T13:10:46Z")

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Is it possible to do a micro-simulation using Agents.jl? Some software pretend to do ABM and micro-simulation. Can it be real? What would be the right packages to do it in Julia?

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## [How to draw a circle of 500m away from a point on a map? or how to highlight all connected ways?](https://discourse.julialang.org/t/how-to-draw-a-circle-of-500m-away-from-a-point-on-a-map-or-how-to-highlight-all-connected-ways/98093)

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**Author:** [@Optimization](https://discourse.julialang.org/u/Optimization)\
**Replies:** 5\
**Last updated:** [April 30, 2023, 12:42pm UTC](https://discourse.julialang.org/t/how-to-draw-a-circle-of-500m-away-from-a-point-on-a-map-or-how-to-highlight-all-connected-ways/98093 "2023-04-30T12:42:36Z")

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Is it possible to draw a circle around a coordinates? I knew that with folium one can plot a points on a map: using OpenStreetMapX using PyCall points = LLA(43.658813, -79.397574, 0.0) using PyCall flm = pyimport("f…

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## [Is there a faster alternative to \`hcat(xx...)\`?](https://discourse.julialang.org/t/is-there-a-faster-alternative-to-hcat-xx/98112)

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**Author:** [@\_stla](https://discourse.julialang.org/u/_stla)\
**Replies:** 16\
**Last updated:** [April 30, 2023, 12:01pm UTC](https://discourse.julialang.org/t/is-there-a-faster-alternative-to-hcat-xx/98112 "2023-04-30T12:01:27Z")

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Hello, I have this piece of code in a function: triangles = Matrix{Int}(undef, 3, 0) for i in 1:ntriangles a, b, c = triangle = ∂₂₀(i) nkeep = tokeep\[a\] + tokeep\[b\] + tokeep\[c\] if nkeep \> 0 push!(…

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## [Add methods to function from another module](https://discourse.julialang.org/t/add-methods-to-function-from-another-module/98083)

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**Author:** [@iskyd](https://discourse.julialang.org/u/iskyd)\
**Replies:** 2\
**Last updated:** [April 30, 2023, 9:53am UTC](https://discourse.julialang.org/t/add-methods-to-function-from-another-module/98083 "2023-04-30T09:53:01Z")

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Hi everyone, I have a module A that simply define a function module A """ f(config::ConnectionConfiguration) Connects to the database using the given configuration. """ function connect end end Now from modul…

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## [Prefixing output columns which are returned as Dataframe](https://discourse.julialang.org/t/prefixing-output-columns-which-are-returned-as-dataframe/98098)

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**Author:** [@mreichMPI-BGC](https://discourse.julialang.org/u/mreichMPI-BGC)\
**Replies:** 9\
**Last updated:** [April 30, 2023, 9:36am UTC](https://discourse.julialang.org/t/prefixing-output-columns-which-are-returned-as-dataframe/98098 "2023-04-30T09:36:31Z")

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Sorry, I am stuck a bit…: Suppose I have a function that takes Vectors and returns a DataFrame of the same length as the Vectors (e.g. my calc function below). function calc(x1,x2) y1 = accumulate(+, x1+x2 .+ 0.1ra…

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## [Probability Outcomes Plot with JULIA for Fair Coin Tossing](https://discourse.julialang.org/t/probability-outcomes-plot-with-julia-for-fair-coin-tossing/94663)

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**Author:** [@Freya\_the\_Goddess](https://discourse.julialang.org/u/Freya_the_Goddess)\
**Replies:** 28\
**Last updated:** [April 30, 2023, 8:52am UTC](https://discourse.julialang.org/t/probability-outcomes-plot-with-julia-for-fair-coin-tossing/94663 "2023-04-30T08:52:03Z")

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Hi all, I want to plot the possible outcomes of tossing a fair coin for n times. If three times tossed then it should be like this graph: Which package in Julia can make this kind of graph?

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