# Latest

**URL:** https://discourse.julialang.org/latest.md?page=1886

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

**Page:** 1887

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## [VSCode crashed, julia process live containing data. Any way to access?](https://discourse.julialang.org/t/vscode-crashed-julia-process-live-containing-data-any-way-to-access/30826)

<div class="topic-metadata">

**Author:** [@BioTurboNick](https://discourse.julialang.org/u/BioTurboNick)\
**Replies:** 1\
**Last updated:** [November 7, 2019, 9:38pm UTC](https://discourse.julialang.org/t/vscode-crashed-julia-process-live-containing-data-any-way-to-access/30826 "2019-11-07T21:38:47Z")

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I had a script running all day but VSCode crashed overnight, taking the output with it. Is there any way to connect to the process and recover the data or determine if there was an error? Is there a log anywhere of the…

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## [How to replace the charactors in the string?](https://discourse.julialang.org/t/how-to-replace-the-charactors-in-the-string/30778)

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**Author:** [@Yan](https://discourse.julialang.org/u/Yan)\
**Replies:** 34\
**Last updated:** [November 7, 2019, 9:24pm UTC](https://discourse.julialang.org/t/how-to-replace-the-charactors-in-the-string/30778 "2019-11-07T21:24:18Z")

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How to realize the following perl translating task in Julia? #/user/bin/perl my $string = ‘The cat sat on the mat’; $string =~ tr/ao/oL/; print “$string\\n”; #------------------------- The cot sot Ln the mot

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## [Why does \`map\` of a named tuple and tuple return an array?](https://discourse.julialang.org/t/why-does-map-of-a-named-tuple-and-tuple-return-an-array/30468)

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**Author:** [@Raf](https://discourse.julialang.org/u/Raf)\
**Replies:** 5\
**Last updated:** [November 7, 2019, 9:03pm UTC](https://discourse.julialang.org/t/why-does-map-of-a-named-tuple-and-tuple-return-an-array/30468 "2019-11-07T21:03:21Z")

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Array seems like a strange return type for this interaction: julia\> map(+, (1, 2), (x=1, y=2)) 2-element Array{Int64,1}: 2 4 Why not tuple?

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## [Github topics no longer list all repositories?](https://discourse.julialang.org/t/github-topics-no-longer-list-all-repositories/30845)

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**Author:** [@chakravala](https://discourse.julialang.org/u/chakravala)\
**Replies:** 1\
**Last updated:** [November 7, 2019, 8:24pm UTC](https://discourse.julialang.org/t/github-topics-no-longer-list-all-repositories/30845 "2019-11-07T20:24:42Z")

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It seems that tagged topics on github no longer list all repositories: https://github.com/topics/julia Previously, all repositories tagged with a topic would be listed and could be filtered in various ways. Now, there …

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## [How to load a collection of image files with Images.jl or ImageView.jl](https://discourse.julialang.org/t/how-to-load-a-collection-of-image-files-with-images-jl-or-imageview-jl/30829)

<div class="topic-metadata">

**Author:** [@LaurentPlagne](https://discourse.julialang.org/u/LaurentPlagne)\
**Replies:** 4\
**Last updated:** [November 7, 2019, 7:35pm UTC](https://discourse.julialang.org/t/how-to-load-a-collection-of-image-files-with-images-jl-or-imageview-jl/30829 "2019-11-07T19:35:48Z")

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I have generated (in //) a collection of image files : toto1.gif, toto2.gif,…,toto100.gif How can I load and visualize them with ImageView.jl ? Laurent

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## [Errors parsing when reading STATA file](https://discourse.julialang.org/t/errors-parsing-when-reading-stata-file/30840)

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**Author:** [@hendri54](https://discourse.julialang.org/u/hendri54)\
**Replies:** 2\
**Last updated:** [November 7, 2019, 7:11pm UTC](https://discourse.julialang.org/t/errors-parsing-when-reading-stata-file/30840 "2019-11-07T19:11:21Z")

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I am reading a STATA file (likely created in 2014; not known which STATA version was used) and get the following error: using DataFrames \[ Info: Precompiling DataFrames \[a93c6f00-e57d-5684-b7b6-d8193f3e46c0\] julia\> usi…

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## [PyPlot 3d plotting](https://discourse.julialang.org/t/pyplot-3d-plotting/30838)

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**Author:** [@programista](https://discourse.julialang.org/u/programista)\
**Replies:** 1\
**Last updated:** [November 7, 2019, 7:02pm UTC](https://discourse.julialang.org/t/pyplot-3d-plotting/30838 "2019-11-07T19:02:49Z")

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Why this code does not work without second line: p1=scatter3D(,0) ? This line is unnecessary for me. How to write it correctly to get one chart, not two ? using PyPlot p1=scatter3D(\[\],0) fig = plt.figure() ax = fig.add…

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## [Does a Julia official standard (reference) exist?](https://discourse.julialang.org/t/does-a-julia-official-standard-reference-exist/30819)

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**Author:** [@sylvaticus](https://discourse.julialang.org/u/sylvaticus)\
**Replies:** 3\
**Last updated:** [November 7, 2019, 6:03pm UTC](https://discourse.julialang.org/t/does-a-julia-official-standard-reference-exist/30819 "2019-11-07T18:03:15Z")

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Just out of curiosity, does an “Official Standard” (or reference) (like the ISO/IEC 14882:2017(E) " C++17" for C++) exists for the Julia language ? Do you think a “standard” would be beneficial? Or, at the opposite, no…

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## [Switching from 1.1 to 1.2, more startup slowness after loading startup file](https://discourse.julialang.org/t/switching-from-1-1-to-1-2-more-startup-slowness-after-loading-startup-file/30832)

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**Author:** [@Usor](https://discourse.julialang.org/u/Usor)\
**Replies:** 4\
**Last updated:** [November 7, 2019, 5:24pm UTC](https://discourse.julialang.org/t/switching-from-1-1-to-1-2-more-startup-slowness-after-loading-startup-file/30832 "2019-11-07T17:24:30Z")

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I understand that there may be some slowness, and I don’t mind it so much, but when I switched from 1.1 to 1.2, Julia became much slower after manually loading a startup file. Though the cursor blinks after loading, pres…

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## [Tuple of Arrays: assigning or accumulating into the first column of each tuple elements](https://discourse.julialang.org/t/tuple-of-arrays-assigning-or-accumulating-into-the-first-column-of-each-tuple-elements/30830)

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**Author:** [@jlchan](https://discourse.julialang.org/u/jlchan)\
**Replies:** 4\
**Last updated:** [November 7, 2019, 5:22pm UTC](https://discourse.julialang.org/t/tuple-of-arrays-assigning-or-accumulating-into-the-first-column-of-each-tuple-elements/30830 "2019-11-07T17:22:25Z")

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I’m trying to apply a matrix A to a single column of each element of X and accumulate into X, where X is a tuple of arrays. N = 2 A = rand(N,N) X = (ones(N,N),ones(N,N)) for fld in eachindex(X) X\[fld\]\[:,1\] += A\*X\[fl…

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## [Initializing an array of mutable objects is surprisingly slow](https://discourse.julialang.org/t/initializing-an-array-of-mutable-objects-is-surprisingly-slow/11780)

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**Author:** [@cnliao](https://discourse.julialang.org/u/cnliao)\
**Replies:** 8\
**Last updated:** [November 7, 2019, 3:13pm UTC](https://discourse.julialang.org/t/initializing-an-array-of-mutable-objects-is-surprisingly-slow/11780 "2019-11-07T15:13:57Z")

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How can one performantly preallocate a vector of mutable objects? Currently allocating and initializing a vector of mutables is ~60x slower than doing the same thing for mutables: # same result on v0.6.3 and latest mast…

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## [Isassigned for blocks in BlockArrays](https://discourse.julialang.org/t/isassigned-for-blocks-in-blockarrays/30831)

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**Author:** [@krcools](https://discourse.julialang.org/u/krcools)\
**Replies:** 0\
**Last updated:** [November 7, 2019, 3:12pm UTC](https://discourse.julialang.org/t/isassigned-for-blocks-in-blockarrays/30831 "2019-11-07T15:12:11Z")

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Is there a way to check that a block in a BlockArray is assigned? I would expect syntax like isassigned(A, Block(2,3))

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## [Rolling Sum](https://discourse.julialang.org/t/rolling-sum/30793)

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**Author:** [@ggjp](https://discourse.julialang.org/u/ggjp)\
**Replies:** 28\
**Last updated:** [November 7, 2019, 2:45pm UTC](https://discourse.julialang.org/t/rolling-sum/30793 "2019-11-07T14:45:36Z")

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What is the recommended way of doing a rolling / moving sum? I’ve found packages RollingFunctions.jl and MarketTechnicals.jl, but neither has this.

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## [Iterating using Channel](https://discourse.julialang.org/t/iterating-using-channel/30762)

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**Author:** [@marouane1994](https://discourse.julialang.org/u/marouane1994)\
**Replies:** 6\
**Last updated:** [November 7, 2019, 1:49pm UTC](https://discourse.julialang.org/t/iterating-using-channel/30762 "2019-11-07T13:49:00Z")

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i have some problems in replacing the deprecated function produce()with Channel()in this code: function scan\_maker(A) m = JuMP.Model(solver=ClpSolver(PrimalTolerance=1e-3, DualTolerance=1e-3, InfeasibleReturn=1, Pre…

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## [Is Julia able to export a module as another (aliased) name?](https://discourse.julialang.org/t/is-julia-able-to-export-a-module-as-another-aliased-name/30814)

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**Author:** [@singularitti](https://discourse.julialang.org/u/singularitti)\
**Replies:** 1\
**Last updated:** [November 7, 2019, 2:41am UTC](https://discourse.julialang.org/t/is-julia-able-to-export-a-module-as-another-aliased-name/30814 "2019-11-07T02:41:11Z")

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I am not the author of Yao.jl. I just want to use it as an example. The source code of Yao.jl is just one simple thing: reexport things defined in its sub-packages. using Reexport @reexport using YaoBase, YaoArrayRegist…

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## [Using Transducers.jl instead of stateful functions for stream processing](https://discourse.julialang.org/t/using-transducers-jl-instead-of-stateful-functions-for-stream-processing/30553)

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**Author:** [@sairus7](https://discourse.julialang.org/u/sairus7)\
**Replies:** 8\
**Last updated:** [November 7, 2019, 9:31am UTC](https://discourse.julialang.org/t/using-transducers-jl-instead-of-stateful-functions-for-stream-processing/30553 "2019-11-07T09:31:05Z")

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Looks like a nice solution for processing buffered streams of signals in chunks and pass its results to next processing steps in a sequense or tree. But can you please explain, how should stateful functions code change…

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## [Extract exponent from numbers in julia](https://discourse.julialang.org/t/extract-exponent-from-numbers-in-julia/30810)

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**Author:** [@Luigi\_Marongiu](https://discourse.julialang.org/u/Luigi_Marongiu)\
**Replies:** 2\
**Last updated:** [November 7, 2019, 8:15am UTC](https://discourse.julialang.org/t/extract-exponent-from-numbers-in-julia/30810 "2019-11-07T08:15:30Z")

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Hello, I have to compare numbers that are quite small – something like 10e-5 or 10e-13 etc. Is there a way to extract the exponent (or characteristic) of the numbers, so that I will be working with -5 and -13 only? (thu…

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## [Check if a type implements an interface in Julia](https://discourse.julialang.org/t/check-if-a-type-implements-an-interface-in-julia/30818)

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**Author:** [@phlavenk](https://discourse.julialang.org/u/phlavenk)\
**Replies:** 1\
**Last updated:** [November 7, 2019, 8:03am UTC](https://discourse.julialang.org/t/check-if-a-type-implements-an-interface-in-julia/30818 "2019-11-07T08:03:00Z")

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I’ used title from a SO question ~3 years old here. Is there a better approach in Julia 1.0+ how to test or dispatch to types that e.g support indexing or iteration, without using methodswith()?

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## [Executing a method given its name as a string](https://discourse.julialang.org/t/executing-a-method-given-its-name-as-a-string/30771)

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**Author:** [@frtps](https://discourse.julialang.org/u/frtps)\
**Replies:** 3\
**Last updated:** [November 7, 2019, 7:37am UTC](https://discourse.julialang.org/t/executing-a-method-given-its-name-as-a-string/30771 "2019-11-07T07:37:28Z")

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I would like to define a macro that would execute a function having been provided its name in a string-valued variable. So the following code gives a naive implementation: macro invoke\_callback(c,args...) = quote eval(S…

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## [Developing Julia interface for Plotly Dash](https://discourse.julialang.org/t/developing-julia-interface-for-plotly-dash/30533)

<div class="topic-metadata">

**Author:** [@waralex](https://discourse.julialang.org/u/waralex)\
**Replies:** 18\
**Last updated:** [November 7, 2019, 7:19am UTC](https://discourse.julialang.org/t/developing-julia-interface-for-plotly-dash/30533 "2019-11-07T07:19:09Z")

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Hi. I’m new to Julia and I need a single-page interactive dashboard. So I wrote the prototype of Julia interface for Plotly Dash - package Dashboards.jl Now it has all the basic functionality of Dash - you can create …

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## [How to clear or close pyplot figure?](https://discourse.julialang.org/t/how-to-clear-or-close-pyplot-figure/30767)

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**Author:** [@programista](https://discourse.julialang.org/u/programista)\
**Replies:** 4\
**Last updated:** [November 7, 2019, 7:00am UTC](https://discourse.julialang.org/t/how-to-clear-or-close-pyplot-figure/30767 "2019-11-07T07:00:48Z")

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How to clear or close pyplot figure? Paul

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## [MethodError: no method matching -(::NTuple{4,Int64}, ::Int64)](https://discourse.julialang.org/t/methoderror-no-method-matching-ntuple-4-int64-int64/30817)

<div class="topic-metadata">

**Author:** [@marinarrd](https://discourse.julialang.org/u/marinarrd)\
**Replies:** 3\
**Last updated:** [November 7, 2019, 4:44am UTC](https://discourse.julialang.org/t/methoderror-no-method-matching-ntuple-4-int64-int64/30817 "2019-11-07T04:44:05Z")

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I am new and dont understand why this doesnt work! original\_cost = npzread("file.npy") size\_cost = size(original\_cost) println('size of original table',size\_cost) left\_index = 40 right\_index = size\_cost - left\_index pri…

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## [What's wrong with this Flux model definitin?](https://discourse.julialang.org/t/whats-wrong-with-this-flux-model-definitin/30816)

<div class="topic-metadata">

**Author:** [@xiaodai](https://discourse.julialang.org/u/xiaodai)\
**Replies:** 1\
**Last updated:** [November 7, 2019, 3:13am UTC](https://discourse.julialang.org/t/whats-wrong-with-this-flux-model-definitin/30816 "2019-11-07T03:13:57Z")

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I am on the latest master branch of Flux.jl using Flux using CuArrays CuArrays.allowscalar(false) x = gpu(rand(Float32, 1\_000\_000, 2)) y = 2 .\* x + gpu(rand(Float32, 1\_000\_000)) w = gpu(rand(2, 1)) loss(x, y) = Flux.m…

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## [Unable to make 3d quiver plot](https://discourse.julialang.org/t/unable-to-make-3d-quiver-plot/30811)

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**Author:** [@alacritas](https://discourse.julialang.org/u/alacritas)\
**Replies:** 1\
**Last updated:** [November 7, 2019, 1:05am UTC](https://discourse.julialang.org/t/unable-to-make-3d-quiver-plot/30811 "2019-11-07T01:05:23Z")

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I have 3 dimensional data, but it looks like the only available package to do this is PyPlot, but this available example is not working with my environment (Julia 1.2.0), and returns an error saying Unkown projection '3d…

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## [Help with recursive type for automatic differentiation (Taylor Numbers) as in a Haskell example](https://discourse.julialang.org/t/help-with-recursive-type-for-automatic-differentiation-taylor-numbers-as-in-a-haskell-example/30804)

<div class="topic-metadata">

**Author:** [@stakaz](https://discourse.julialang.org/u/stakaz)\
**Replies:** 11\
**Last updated:** [November 7, 2019, 1:06am UTC](https://discourse.julialang.org/t/help-with-recursive-type-for-automatic-differentiation-taylor-numbers-as-in-a-haskell-example/30804 "2019-11-07T01:06:28Z")

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Hello, I am about to try out to implement Taylor numbers for automatic differentiation (just as a simple example for myself). Y have found a very neat version written in Haskell here: Automatic Differentiation: Dual numb…

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## [Similar performance using DataFrames or DataFramesMeta?](https://discourse.julialang.org/t/similar-performance-using-dataframes-or-dataframesmeta/30813)

<div class="topic-metadata">

**Author:** [@bashonubuntu](https://discourse.julialang.org/u/bashonubuntu)\
**Replies:** 0\
**Last updated:** [November 7, 2019, 1:04am UTC](https://discourse.julialang.org/t/similar-performance-using-dataframes-or-dataframesmeta/30813 "2019-11-07T01:04:31Z")

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In my experience, DataFrames and DataFramesMeta have performed quite similarly in typical use-cases like selecting a subset of a dataframe based on a condition, selecting a column from a dataframe etc. Have other users f…

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## [Does Julia have an index symbol ! like Haskell?](https://discourse.julialang.org/t/does-julia-have-an-index-symbol-like-haskell/30787)

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**Author:** [@AlexanderChen](https://discourse.julialang.org/u/AlexanderChen)\
**Replies:** 17\
**Last updated:** [November 7, 2019, 12:12am UTC](https://discourse.julialang.org/t/does-julia-have-an-index-symbol-like-haskell/30787 "2019-11-07T00:12:17Z")

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Hi, In Haskell you have the !! symbol which is used as follows: a = \[1,2,3\] a !! 2 Output: 3 (haskell is 0-based) I find this quite handy but i can only find a regular index method in Julia: a\[3\] = 3 Does Julia ha…

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## [Remote: support alternate sftp extensions](https://discourse.julialang.org/t/remote-support-alternate-sftp-extensions/30809)

<div class="topic-metadata">

**Author:** [@FredC](https://discourse.julialang.org/u/FredC)\
**Replies:** 1\
**Last updated:** [November 6, 2019, 10:25pm UTC](https://discourse.julialang.org/t/remote-support-alternate-sftp-extensions/30809 "2019-11-06T22:25:56Z")

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The ftp-remote-edit extension stores encrypted connection information. Other extensions are more conventional in allowing a per-session password input. Remote FTP, for example. The ability to use that package for SFTP ac…

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## [Siggraph 2019](https://discourse.julialang.org/t/siggraph-2019/27281)

<div class="topic-metadata">

**Author:** [@Orbots](https://discourse.julialang.org/u/Orbots)\
**Replies:** 9\
**Last updated:** [November 6, 2019, 9:28pm UTC](https://discourse.julialang.org/t/siggraph-2019/27281 "2019-11-06T21:28:34Z")

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Any other Julian’s in the Computer Graphics domain? Julia is such an excellent fit here. Look at all that numerical programming: Technical Papers - SIGGRAPH 2019 Sadly not a single mention of Julia that i ran across …

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## [Efficient way to handle operator splitting (periodically updating solution mid-solve) in JuliaDiffEq](https://discourse.julialang.org/t/efficient-way-to-handle-operator-splitting-periodically-updating-solution-mid-solve-in-juliadiffeq/30757)

<div class="topic-metadata">

**Author:** [@jimmielin](https://discourse.julialang.org/u/jimmielin)\
**Replies:** 3\
**Last updated:** [November 6, 2019, 9:04pm UTC](https://discourse.julialang.org/t/efficient-way-to-handle-operator-splitting-periodically-updating-solution-mid-solve-in-juliadiffeq/30757 "2019-11-06T21:04:29Z")

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I am writing a simple model of atmospheric chemistry in Julia using DifferentialEquations.jl to solve the chemical kinetics ODEs. While chemical kinetics can be modeled using a system of ODEs, some processes in modern a…

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