# Latest

**URL:** https://discourse.julialang.org/latest.md?page=1232

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

**Page:** 1233

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## [Unable to successfully read sqlserver Date datatype \[ODBC, DataFrames\]](https://discourse.julialang.org/t/unable-to-successfully-read-sqlserver-date-datatype-odbc-dataframes/70072)

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**Author:** [@vtomar](https://discourse.julialang.org/u/vtomar)\
**Replies:** 1\
**Last updated:** [October 20, 2021, 8:13pm UTC](https://discourse.julialang.org/t/unable-to-successfully-read-sqlserver-date-datatype-odbc-dataframes/70072 "2021-10-20T20:13:01Z")

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i have a very simple query: using ODBC, Dates, DataFrames query = "select id, convert(date, ColumnName1) as CalendarDate from table1" conn = DBInterface.connect(ODBC.Connection, "ConnectionString"); statement = DBInter…

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## [Ordering multivariate polynomials (AbstractAlgebra)](https://discourse.julialang.org/t/ordering-multivariate-polynomials-abstractalgebra/69779)

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**Author:** [@Gilles\_Dubois](https://discourse.julialang.org/u/Gilles_Dubois)\
**Replies:** 4\
**Last updated:** [October 20, 2021, 7:50pm UTC](https://discourse.julialang.org/t/ordering-multivariate-polynomials-abstractalgebra/69779 "2021-10-20T19:50:05Z")

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Bonjour à tous ! I’m working now with multivariate polynomials of the AbstractAlgebra package Everything works well, but I have a problem with ordering. To make simple let’s consider the case of only 2 variables say ‘…

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## [Tuple size issues](https://discourse.julialang.org/t/tuple-size-issues/70107)

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**Author:** [@Brock](https://discourse.julialang.org/u/Brock)\
**Replies:** 2\
**Last updated:** [October 20, 2021, 7:49pm UTC](https://discourse.julialang.org/t/tuple-size-issues/70107 "2021-10-20T19:49:59Z")

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When I run a small size problem I don’t have issues but when my problem is larger my code crashes with some kind of exception error. I will paste the error below. I was able to isolate the issue. It is due to the size of…

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## [Best method for calculating the second derivative of 1D array](https://discourse.julialang.org/t/best-method-for-calculating-the-second-derivative-of-1d-array/69353)

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**Author:** [@AngusRussell](https://discourse.julialang.org/u/AngusRussell)\
**Replies:** 11\
**Last updated:** [October 20, 2021, 7:45pm UTC](https://discourse.julialang.org/t/best-method-for-calculating-the-second-derivative-of-1d-array/69353 "2021-10-20T19:45:06Z")

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Essentially I have 1D arrays of eigenvalues as shown in the above plot and I want to find the 2nd derivative of each energy band with respect to ϵ. My current method uses Dierckx.jl. In my code, the eigenvalues are …

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## [JSON parsing gives error message with Dash](https://discourse.julialang.org/t/json-parsing-gives-error-message-with-dash/70104)

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**Author:** [@stanlazic](https://discourse.julialang.org/u/stanlazic)\
**Replies:** 1\
**Last updated:** [October 20, 2021, 7:41pm UTC](https://discourse.julialang.org/t/json-parsing-gives-error-message-with-dash/70104 "2021-10-20T19:41:46Z")

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This code runs fine and JSON.parse() works as expected. using Dash using DataFrames using CSV using Base64 using JSON # example data data\_dict = Dict("group" =\> \["A", "A", "B", "B"\], "height" =\> \[1, 2,…

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## [Lazy logspace object](https://discourse.julialang.org/t/lazy-logspace-object/70091)

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**Author:** [@juliohm](https://discourse.julialang.org/u/juliohm)\
**Replies:** 3\
**Last updated:** [October 20, 2021, 7:40pm UTC](https://discourse.julialang.org/t/lazy-logspace-object/70091 "2021-10-20T19:40:03Z")

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We still miss a lazy version as a range. The broadcast solution above is greedy and breaks code that expects range objects.

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## [Datastructure for lazy evalulation](https://discourse.julialang.org/t/datastructure-for-lazy-evalulation/48972)

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**Author:** [@lobingera](https://discourse.julialang.org/u/lobingera)\
**Replies:** 0\
**Last updated:** [October 25, 2020, 10:11am UTC](https://discourse.julialang.org/t/datastructure-for-lazy-evalulation/48972 "2020-10-25T10:11:28Z")

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I’m working on some visualization things and i think i need a datastructure to capture relations between ‘objects’ or ‘data’ so that i can track down the minimum set of updates. So like A depends on B and C and if C or …

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## [Fastest package for Desktop Screenshots](https://discourse.julialang.org/t/fastest-package-for-desktop-screenshots/70103)

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**Author:** [@Pytrator](https://discourse.julialang.org/u/Pytrator)\
**Replies:** 1\
**Last updated:** [October 20, 2021, 6:32pm UTC](https://discourse.julialang.org/t/fastest-package-for-desktop-screenshots/70103 "2021-10-20T18:32:33Z")

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Hey guys, i am fairly new to Julia and i spent the past days on looking through packages that would help me to get all the features that pyautogui has. For mouse and keyboard automation i found Readme · GLFWAbstraction.…

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## [Performance speed up when wrapping script with Juno.@profiler](https://discourse.julialang.org/t/performance-speed-up-when-wrapping-script-with-juno-profiler/70078)

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**Author:** [@saul.ssto](https://discourse.julialang.org/u/saul.ssto)\
**Replies:** 4\
**Last updated:** [October 20, 2021, 6:22pm UTC](https://discourse.julialang.org/t/performance-speed-up-when-wrapping-script-with-juno-profiler/70078 "2021-10-20T18:22:48Z")

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Hello, I’m trying to simulate the Belousov-Zhabotinsky (BZ) reaction as implemented here. I have written the following implementation for that purpose: using Images, ImageView, ProgressMeter function react(petridish::…

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## [Using callback during adjoint method for NeuralODE](https://discourse.julialang.org/t/using-callback-during-adjoint-method-for-neuralode/70076)

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**Author:** [@xk\_y](https://discourse.julialang.org/u/xk_y)\
**Replies:** 4\
**Last updated:** [October 20, 2021, 6:16pm UTC](https://discourse.julialang.org/t/using-callback-during-adjoint-method-for-neuralode/70076 "2021-10-20T18:16:05Z")

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I am training a neural ode with a callback function to add a certain value at every integration timestep. The forward pass works but an error occur during backpropagation. I was wondering if the adjoint method supports a…

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## [Ever wanted to automate your keyboard and mouse and perform clicks/take screenshots?](https://discourse.julialang.org/t/ever-wanted-to-automate-your-keyboard-and-mouse-and-perform-clicks-take-screenshots/41848)

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**Author:** [@SubhadityaMukherjee](https://discourse.julialang.org/u/SubhadityaMukherjee)\
**Replies:** 1\
**Last updated:** [October 20, 2021, 4:06pm UTC](https://discourse.julialang.org/t/ever-wanted-to-automate-your-keyboard-and-mouse-and-perform-clicks-take-screenshots/41848 "2021-10-20T16:06:26Z")

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I could not find any package to automate the keyboard/mouse so I built a wrapper of a Python library using PyCall. This allows you to perform complex key clicks/take screenshots/scroll etc using Julia syntax/arrays etc!!…

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## [How to start Julia REPL in VS CODE (Insiders) in specified conda environment?](https://discourse.julialang.org/t/how-to-start-julia-repl-in-vs-code-insiders-in-specified-conda-environment/63505)

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**Author:** [@anon28281882](https://discourse.julialang.org/u/anon28281882)\
**Replies:** 14\
**Last updated:** [October 20, 2021, 3:10pm UTC](https://discourse.julialang.org/t/how-to-start-julia-repl-in-vs-code-insiders-in-specified-conda-environment/63505 "2021-10-20T15:10:27Z")

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I use VS CODE 1.58.0 (Insiders) and SSH connection to connect to Ubuntu 18.04.5 LTS and conda environment (env name: base). I have several conda environments. One of them is destined for Julia with Julia 1.6 (env name: j…

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## [Understanding \`sizeof\` return values on \`Char\` / \`String\`](https://discourse.julialang.org/t/understanding-sizeof-return-values-on-char-string/70099)

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**Author:** [@BambOoxX](https://discourse.julialang.org/u/BambOoxX)\
**Replies:** 2\
**Last updated:** [October 20, 2021, 2:56pm UTC](https://discourse.julialang.org/t/understanding-sizeof-return-values-on-char-string/70099 "2021-10-20T14:56:09Z")

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Can someone explain this behavior of sizeof vs summarysize ? sizeof("z") # 1 sizeof('z') # 4 Base.summarysize('z') # 4 Base.summarysize("z") # 9 When I read the doc sizeof(str::AbstractString) Size, in bytes, of the…

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## [CellmlToolkit.jl: How to get observables?](https://discourse.julialang.org/t/cellmltoolkit-jl-how-to-get-observables/69151)

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**Author:** [@andreypikunov](https://discourse.julialang.org/u/andreypikunov)\
**Replies:** 3\
**Last updated:** [October 20, 2021, 2:19pm UTC](https://discourse.julialang.org/t/cellmltoolkit-jl-how-to-get-observables/69151 "2021-10-20T14:19:59Z")

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Hello! Using Beeler-Reuter model from the README I can list observables: julia\> ml = CellModel("models/beeler\_reuter\_1977.cellml.xml") julia\> observed(ml.sys) 39-element Vector{Equation}: slow\_inward\_current\_f\_gate₊V(…

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## [Object detection and Classification using PointCloud data in Julia?](https://discourse.julialang.org/t/object-detection-and-classification-using-pointcloud-data-in-julia/70097)

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**Author:** [@DoktorMike](https://discourse.julialang.org/u/DoktorMike)\
**Replies:** 0\
**Last updated:** [October 20, 2021, 1:57pm UTC](https://discourse.julialang.org/t/object-detection-and-classification-using-pointcloud-data-in-julia/70097 "2021-10-20T13:57:10Z")

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I recently came across an interesting problem where I need to do object detection and classification in a 3D PointCloud. I found some implementations for a few networks in PyTorch but didn’t find any in Julia. Flux3D doe…

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## [How to do \`logspace()\` in Julia v. 1.0.x?](https://discourse.julialang.org/t/how-to-do-logspace-in-julia-v-1-0-x/17452)

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**Author:** [@BLI](https://discourse.julialang.org/u/BLI)\
**Replies:** 4\
**Last updated:** [November 12, 2018, 11:37pm UTC](https://discourse.julialang.org/t/how-to-do-logspace-in-julia-v-1-0-x/17452 "2018-11-12T23:37:35Z")

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Silly question, I guess… So: linspace() has been replaced by range(). But what about logspace()? I tried to do it manually as, e.g., 10.^(range(-2,stop=2,length=50)), but that doesn’t work. Is there a built-in new f…

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## [Add vs dev at a local path](https://discourse.julialang.org/t/add-vs-dev-at-a-local-path/58150)

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**Author:** [@erans](https://discourse.julialang.org/u/erans)\
**Replies:** 10\
**Last updated:** [October 20, 2021, 11:19am UTC](https://discourse.julialang.org/t/add-vs-dev-at-a-local-path/58150 "2021-10-20T11:19:44Z")

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Hello all, I’m still a bit confused about the difference between adding and developing a package at a local path. so: (@v1.4) pkg\> add \<path\>/\<to\>/\<my\>/\<package\> versus (@v1.4) pkg\> dev \<path\>/\<to\>/\<my\>/\<package\> I…

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## [\[ANN\] TableDistances.jl](https://discourse.julialang.org/t/ann-tabledistances-jl/69770)

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**Author:** [@juliohm](https://discourse.julialang.org/u/juliohm)\
**Replies:** 1\
**Last updated:** [October 16, 2021, 1:04am UTC](https://discourse.julialang.org/t/ann-tabledistances-jl/69770 "2021-10-16T01:04:00Z")

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TableDistances.jl is a Julia package for computing distances between observations with heterogeneous attributes (e.g. continuous, categorical). This functionality is widely used in various machine learning methods such a…

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## [Precompiling RDatasets returns LoadError on CodecZlib.jl](https://discourse.julialang.org/t/precompiling-rdatasets-returns-loaderror-on-codeczlib-jl/40829)

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**Author:** [@aebk2015](https://discourse.julialang.org/u/aebk2015)\
**Replies:** 2\
**Last updated:** [October 20, 2021, 10:30am UTC](https://discourse.julialang.org/t/precompiling-rdatasets-returns-loaderror-on-codeczlib-jl/40829 "2021-10-20T10:30:06Z")

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I installed RDatasets but when I am calling it; it complains CodecZlib is not installed properly but even after I rebuild the CodecZlib ( Pkg.build("CodecZlib")), the error remains the same using RDatasets ┌ Info: Prec…

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## [Multithreading on entries sparse matrix](https://discourse.julialang.org/t/multithreading-on-entries-sparse-matrix/70023)

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**Author:** [@ismedina](https://discourse.julialang.org/u/ismedina)\
**Replies:** 5\
**Last updated:** [October 20, 2021, 9:40am UTC](https://discourse.julialang.org/t/multithreading-on-entries-sparse-matrix/70023 "2021-10-20T09:40:47Z")

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In my work I usually have to perform some operations on sparse matrices that involve mostly checking which entries are still important and remove those that are not. I thought that I could use multithreading for that, bu…

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## [No backend available (GLMakie, CairoMakie, WGLMakie)](https://discourse.julialang.org/t/no-backend-available-glmakie-cairomakie-wglmakie/62984)

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**Author:** [@imantha](https://discourse.julialang.org/u/imantha)\
**Replies:** 25\
**Last updated:** [October 20, 2021, 9:38am UTC](https://discourse.julialang.org/t/no-backend-available-glmakie-cairomakie-wglmakie/62984 "2021-10-20T09:38:47Z")

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Hi, I followed one of the tutorial from Agents.jl package.(Schelling's segregation model · Agents.jl) However after executing the following lines of code, I got an error ERROR No backend available (GLMakie, CairoMakie, …

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## [Public package as plugin](https://discourse.julialang.org/t/public-package-as-plugin/69911)

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**Author:** [@kalcool](https://discourse.julialang.org/u/kalcool)\
**Replies:** 10\
**Last updated:** [October 20, 2021, 9:36am UTC](https://discourse.julialang.org/t/public-package-as-plugin/69911 "2021-10-20T09:36:55Z")

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Hi there, I am developing a program that should have a plugin system. I am thinking of using Julia’s package system for this purpose. The idea is that you install a Julia package with additional functionality and when y…

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## [Juliacon21-gpu\_workshop kernel abstractions heat diffusion](https://discourse.julialang.org/t/juliacon21-gpu-workshop-kernel-abstractions-heat-diffusion/70048)

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**Author:** [@Ludovic\_Dumoulin](https://discourse.julialang.org/u/Ludovic_Dumoulin)\
**Replies:** 2\
**Last updated:** [October 20, 2021, 8:24am UTC](https://discourse.julialang.org/t/juliacon21-gpu-workshop-kernel-abstractions-heat-diffusion/70048 "2021-10-20T08:24:43Z")

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Hi, I am trying to reproduce the Juliacon21-gpu workshop and I am stuck at the last part of kernel abstractions. I wrote: @kernel function diffuse\_kabs\_lmem!(out, @Const(data), a, dt, dx, dy) i, j = @index(Global,…

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## [Determining dimension of array via position of "for" and "," in list comprehension](https://discourse.julialang.org/t/determining-dimension-of-array-via-position-of-for-and-in-list-comprehension/70027)

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**Author:** [@pboes](https://discourse.julialang.org/u/pboes)\
**Replies:** 5\
**Last updated:** [October 20, 2021, 7:58am UTC](https://discourse.julialang.org/t/determining-dimension-of-array-via-position-of-for-and-in-list-comprehension/70027 "2021-10-20T07:58:28Z")

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I am new to Julia and noticed the following when playing around with list comprehensions: Given some integers a, b,c, the comprehension \[\[i,j\] for i=1:a for j=1:b\] returns an a\*b \\times 1 array while \[\[i,j\] for i=1:a…

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## [Replace two substrings in a string with the same \`replace\` call?](https://discourse.julialang.org/t/replace-two-substrings-in-a-string-with-the-same-replace-call/70053)

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**Author:** [@BambOoxX](https://discourse.julialang.org/u/BambOoxX)\
**Replies:** 2\
**Last updated:** [October 20, 2021, 7:47am UTC](https://discourse.julialang.org/t/replace-two-substrings-in-a-string-with-the-same-replace-call/70053 "2021-10-20T07:47:00Z")

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I just found that replace could be used to replace two bits of a vector as in replace(\[1, 2, 1, 3\], 1=\>0, 2=\>4) Where the replacements are defined using Pair. I tried that with a string instead of an integer vector, b…

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## [Fast way to calculate statistics of an array based on values (labels) of another array](https://discourse.julialang.org/t/fast-way-to-calculate-statistics-of-an-array-based-on-values-labels-of-another-array/70054)

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**Author:** [@Bjorn\_De](https://discourse.julialang.org/u/Bjorn_De)\
**Replies:** 7\
**Last updated:** [October 20, 2021, 7:17am UTC](https://discourse.julialang.org/t/fast-way-to-calculate-statistics-of-an-array-based-on-values-labels-of-another-array/70054 "2021-10-20T07:17:42Z")

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Hey, I have two arrays of the same size (10000x10000). One array include labels as result of an segmentation. What I want is to compute statistics for each of these segments based on the 2nd array. My approach is very s…

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## [Resources on creating Dash apps in Julia](https://discourse.julialang.org/t/resources-on-creating-dash-apps-in-julia/69866)

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**Author:** [@mohamed82008](https://discourse.julialang.org/u/mohamed82008)\
**Replies:** 3\
**Last updated:** [October 20, 2021, 4:19am UTC](https://discourse.julialang.org/t/resources-on-creating-dash-apps-in-julia/69866 "2021-10-20T04:19:54Z")

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I found a lot of scattered resources on building Dash apps in Julia and I thought I can put them all in one place here. If you have more, please share below. Dash documentation The Dash Julia documentation https://dash.…

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## [Julia REPL don't update VsCode YES!?](https://discourse.julialang.org/t/julia-repl-dont-update-vscode-yes/70081)

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**Author:** [@HerAdri](https://discourse.julialang.org/u/HerAdri)\
**Replies:** 0\
**Last updated:** [October 20, 2021, 4:04am UTC](https://discourse.julialang.org/t/julia-repl-dont-update-vscode-yes/70081 "2021-10-20T04:04:42Z")

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## [External command interpolation without quoting spaces](https://discourse.julialang.org/t/external-command-interpolation-without-quoting-spaces/70075)

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**Author:** [@chkwon](https://discourse.julialang.org/u/chkwon)\
**Replies:** 2\
**Last updated:** [October 20, 2021, 12:23am UTC](https://discourse.julialang.org/t/external-command-interpolation-without-quoting-spaces/70075 "2021-10-20T00:23:23Z")

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program = "my\_program" options = \["-t 10", "-r 5"\] command = \`$(program) $(options)\` @show command # I get \`my\_program '-t 10' '-r 5'\` # I want \`my\_program -t 10 -r 5\` In the above, I want to pass several options t…

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## [\[ANN\] TypeParams.jl - Generic type parameters without the fuss](https://discourse.julialang.org/t/ann-typeparams-jl-generic-type-parameters-without-the-fuss/67843)

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**Author:** [@ettersi](https://discourse.julialang.org/u/ettersi)\
**Replies:** 6\
**Last updated:** [October 20, 2021, 12:12am UTC](https://discourse.julialang.org/t/ann-typeparams-jl-generic-type-parameters-without-the-fuss/67843 "2021-10-20T00:12:39Z")

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Problem A key feature of Julia is that type annotations are not usually needed to achieve optimal performance. For example, foo(1,2) runs equally fast regardless whether foo() is defined as foo(a,b) = ... or foo(a::Int,…

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