# Latest

**URL:** https://discourse.julialang.org/latest.md?page=1735

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

**Page:** 1736

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## [Append to zipped CSV file](https://discourse.julialang.org/t/append-to-zipped-csv-file/40321)

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**Author:** [@HenrikM](https://discourse.julialang.org/u/HenrikM)\
**Replies:** 4\
**Last updated:** [May 28, 2020, 1:33pm UTC](https://discourse.julialang.org/t/append-to-zipped-csv-file/40321 "2020-05-28T13:33:42Z")

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Hello, I have a program that outputs numerical data. Currently I’m appending into a CSV file so that the progress is saved even if the program is suddenly terminated. Please find the MWE below. How could I output to an…

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## [Structuring Julia Project](https://discourse.julialang.org/t/structuring-julia-project/40327)

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**Author:** [@akhil\_teja](https://discourse.julialang.org/u/akhil_teja)\
**Replies:** 5\
**Last updated:** [May 28, 2020, 10:41am UTC](https://discourse.julialang.org/t/structuring-julia-project/40327 "2020-05-28T10:41:45Z")

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Hi Community, I’m trying to structure my Julia Project but failing to import modules from one dir to another dir. Below is my Project Structure |--Algorithms |-- src |--Algebra |-- algebra.jl …

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## [Different dispatch for positional/keyword arguments](https://discourse.julialang.org/t/different-dispatch-for-positional-keyword-arguments/40269)

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**Author:** [@sylvaticus](https://discourse.julialang.org/u/sylvaticus)\
**Replies:** 5\
**Last updated:** [May 28, 2020, 9:50am UTC](https://discourse.julialang.org/t/different-dispatch-for-positional-keyword-arguments/40269 "2020-05-28T09:50:05Z")

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I am trying to implement multiple dispatch to give users a default option but also rise an error if the type chosen doesn’t implement the specific method. It works fine if the method implement positional argument, but n…

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## [Sticker graphics file](https://discourse.julialang.org/t/sticker-graphics-file/25640)

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**Author:** [@Tamas\_Papp](https://discourse.julialang.org/u/Tamas_Papp)\
**Replies:** 17\
**Last updated:** [May 28, 2020, 8:53am UTC](https://discourse.julialang.org/t/sticker-graphics-file/25640 "2020-05-28T08:53:03Z")

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I am beginning to think that the only way I can obtain some Julia stickers is to have them printed myself. Is there an SVG or PDF format file available that I could use for this? I will try to get an quote for an UV-re…

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## [Error when starting JuliaPro v1.4.1](https://discourse.julialang.org/t/error-when-starting-juliapro-v1-4-1/40223)

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**Author:** [@akahs](https://discourse.julialang.org/u/akahs)\
**Replies:** 9\
**Last updated:** [May 28, 2020, 8:45am UTC](https://discourse.julialang.org/t/error-when-starting-juliapro-v1-4-1/40223 "2020-05-28T08:45:55Z")

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Just installed JuliaPro v1.4.1 and seeing the following error when starting Julia… Starting Julia... \[ Info: Precompiling Atom \[c52e3926-4ff0-5f6e-af25-54175e0327b1\] ERROR: LoadError: LoadError: ArgumentError: Package A…

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## [The least readable name in standard Julia](https://discourse.julialang.org/t/the-least-readable-name-in-standard-julia/40216)

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**Author:** [@pauljurczak](https://discourse.julialang.org/u/pauljurczak)\
**Replies:** 34\
**Last updated:** [May 28, 2020, 7:19am UTC](https://discourse.julialang.org/t/the-least-readable-name-in-standard-julia/40216 "2020-05-28T07:19:09Z")

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I hope I’m not pushing my luck with this post. :grinning: Julia would be more perfect in my eye with camelCase names. I just run into atreplinit(f) for the first time and it got me into deer caught in the headlights mod…

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## [New Julia book, oriented towards Machine Learning](https://discourse.julialang.org/t/new-julia-book-oriented-towards-machine-learning/40319)

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**Author:** [@zvoulgaris](https://discourse.julialang.org/u/zvoulgaris)\
**Replies:** 4\
**Last updated:** [May 28, 2020, 8:22am UTC](https://discourse.julialang.org/t/new-julia-book-oriented-towards-machine-learning/40319 "2020-05-28T08:22:36Z")

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Hello everyone, As per Andrew’s suggestion, I’m posting this here, so that it can be added to the Get started with Julia part of the website. Book title: Julia for Machine Learning Author: Zacharias Voulgaris Publish…

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## [\[ANN\] LoopVectorization](https://discourse.julialang.org/t/ann-loopvectorization/32843)

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**Author:** [@Elrod](https://discourse.julialang.org/u/Elrod)\
**Replies:** 157\
**Last updated:** [May 27, 2020, 12:47pm UTC](https://discourse.julialang.org/t/ann-loopvectorization/32843 "2020-05-27T12:47:30Z")

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I’m excited to announce LoopVectorization. LoopVectorization provides the @avx macro. This macro can be prepended to a for loop or a broadcast statement, and it tries its best to vectorize the loop. It can handle nest…

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## [Julia for prototyping, compared to MATLAB?](https://discourse.julialang.org/t/julia-for-prototyping-compared-to-matlab/33900)

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**Author:** [@ElectronicTeaCup](https://discourse.julialang.org/u/ElectronicTeaCup)\
**Replies:** 70\
**Last updated:** [May 28, 2020, 5:03am UTC](https://discourse.julialang.org/t/julia-for-prototyping-compared-to-matlab/33900 "2020-05-28T05:03:47Z")

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I was talking to a colleague, and they were basically telling me how they would not want to use Julia because most of their time is actually spent on trying different analyses, and exploring data. And for that MATLAB is …

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## [Macro: no method matching size](https://discourse.julialang.org/t/macro-no-method-matching-size/40311)

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**Author:** [@BMval](https://discourse.julialang.org/u/BMval)\
**Replies:** 2\
**Last updated:** [May 28, 2020, 3:51am UTC](https://discourse.julialang.org/t/macro-no-method-matching-size/40311 "2020-05-28T03:51:28Z")

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Would you help me with Macros Why macros does not see functions: size() or length()? Julia ver 1.1.1 macro test\_macro(e::Expr) return (ones(size(e)\[1\]) .+ e) end MethodError: no method matching size(::Expr) Closest…

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## [Gc() function no longer exists?](https://discourse.julialang.org/t/gc-function-no-longer-exists/40310)

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**Author:** [@dlakelan](https://discourse.julialang.org/u/dlakelan)\
**Replies:** 3\
**Last updated:** [May 28, 2020, 2:58am UTC](https://discourse.julialang.org/t/gc-function-no-longer-exists/40310 "2020-05-28T02:58:11Z")

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I start up julia from the command line using 1.4.1 (from Debian packages) and run: dlakelan@pingpong:~$ julia \_ \_ \_ \_(\_)\_ | Documentation: https://docs.julialang.org (\_) | (\_) (\_) |…

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## [Help? for deprecated and renamed items](https://discourse.julialang.org/t/help-for-deprecated-and-renamed-items/40307)

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**Author:** [@virtualgraham](https://discourse.julialang.org/u/virtualgraham)\
**Replies:** 1\
**Last updated:** [May 28, 2020, 2:00am UTC](https://discourse.julialang.org/t/help-for-deprecated-and-renamed-items/40307 "2020-05-28T02:00:10Z")

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It would be great if Julia help? would offer suggestions for deprecated and renamed items. Many times I have searched Google and found posted solutions that use functions or keywords that have since been deprecated or re…

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## [Does \`GC.@preserve a b\` preserves the location of \`a\` and \`b\`](https://discourse.julialang.org/t/does-gc-preserve-a-b-preserves-the-location-of-a-and-b/40233)

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**Author:** [@xiaodai](https://discourse.julialang.org/u/xiaodai)\
**Replies:** 11\
**Last updated:** [May 28, 2020, 12:42am UTC](https://discourse.julialang.org/t/does-gc-preserve-a-b-preserves-the-location-of-a-and-b/40233 "2020-05-28T00:42:22Z")

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I am using GC.@preserve in my code as follows GC.@preserve missing\_bytes res begin src\_ptr = Ptr{UInt8}(pointer(missing\_bytes)) dest\_ptr = Ptr{UInt8}(pointer(res, res\_len+1)) + from - 1 # copy content over …

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## [Left over temporary files when adding a "jll" file](https://discourse.julialang.org/t/left-over-temporary-files-when-adding-a-jll-file/40287)

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**Author:** [@pixel27](https://discourse.julialang.org/u/pixel27)\
**Replies:** 4\
**Last updated:** [May 27, 2020, 11:52pm UTC](https://discourse.julialang.org/t/left-over-temporary-files-when-adding-a-jll-file/40287 "2020-05-27T23:52:02Z")

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When adding Leptonica\_jll with the Pkg I’m left with 23 small files in /tmp'. This is from a clean system when no ~/.julia\` directory exists: As an example: jl\_1l4NBI-download.gz.sha256 jl\_5vHlCu-download.gz.sha256 jl\_…

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## [Exponentiation in Julia](https://discourse.julialang.org/t/exponentiation-in-julia/40299)

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**Author:** [@vettukal](https://discourse.julialang.org/u/vettukal)\
**Replies:** 3\
**Last updated:** [May 27, 2020, 11:41pm UTC](https://discourse.julialang.org/t/exponentiation-in-julia/40299 "2020-05-27T23:41:47Z")

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Hi Julia community, I am a new Julia user. Like what I see till now but with sometimes its head twisting. For example today I saw something and I wanted to know the difference between (-(0.5/1))^1.5 vs -(0.5/1)^1…

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## [Julia stickers?](https://discourse.julialang.org/t/julia-stickers/40198)

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**Author:** [@angelv](https://discourse.julialang.org/u/angelv)\
**Replies:** 1\
**Last updated:** [May 27, 2020, 11:36pm UTC](https://discourse.julialang.org/t/julia-stickers/40198 "2020-05-27T23:36:34Z")

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Don’t know why, but suddenly felt the urge to have one of those flashy stickers with the Julia logo to put on my laptop. Who do I have to bribe to get one of those? :slight\_smile: Cheers, AdV

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## [\[SOLVED : SDL binding\] SDL or similar in Julia?](https://discourse.julialang.org/t/solved-sdl-binding-sdl-or-similar-in-julia/40300)

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**Author:** [@lhp22](https://discourse.julialang.org/u/lhp22)\
**Replies:** 2\
**Last updated:** [May 27, 2020, 11:22pm UTC](https://discourse.julialang.org/t/solved-sdl-binding-sdl-or-similar-in-julia/40300 "2020-05-27T23:22:04Z")

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Hi there ! Is there any package in Julia which provide low level access as SDL ? Or at least the possibility to change screen through the pixel array ? (I wanted to try to make a little 2D game with Julia, to learn more…

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## [\[SOLVED\] UInt is not Int!](https://discourse.julialang.org/t/solved-uint-is-not-int/40038)

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**Author:** [@lhp22](https://discourse.julialang.org/u/lhp22)\
**Replies:** 13\
**Last updated:** [May 27, 2020, 11:07pm UTC](https://discourse.julialang.org/t/solved-uint-is-not-int/40038 "2020-05-27T23:07:35Z")

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Hi ! I’ve encountered something curious, and here is a minimal example :slight\_smile: function f(x::UInt,y::UInt)::UInt x + y end And now i want to do f(2,2) but julia says this to me : julia\> f(2,2) ERROR: Meth…

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## [DifferentialEquations Pkg first use](https://discourse.julialang.org/t/differentialequations-pkg-first-use/40286)

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**Author:** [@A.U.M](https://discourse.julialang.org/u/A.U.M)\
**Replies:** 2\
**Last updated:** [May 27, 2020, 9:46pm UTC](https://discourse.julialang.org/t/differentialequations-pkg-first-use/40286 "2020-05-27T21:46:09Z")

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Hello, It’s my first time to use DifferentialEquations Pkg. I used this documentation ( https://docs.sciml.ai/stable/tutorials/ode\_example/) to do some tutorial and when I run the same code in the documentation using J…

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## [How to declare parametric with return type of a function?](https://discourse.julialang.org/t/how-to-declare-parametric-with-return-type-of-a-function/40288)

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**Author:** [@Ronneesley](https://discourse.julialang.org/u/Ronneesley)\
**Replies:** 3\
**Last updated:** [May 27, 2020, 8:45pm UTC](https://discourse.julialang.org/t/how-to-declare-parametric-with-return-type-of-a-function/40288 "2020-05-27T20:45:06Z")

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I have a method and I want to declare it with parametric and with return type. What is the syntax? f(a::T)::Bool where {T \<: Number} = a == 1 The error message is: ERROR: UndefVarError: T not defined Stacktrace: \[1\]…

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## [Inspecting values of default and optional arguments of a function](https://discourse.julialang.org/t/inspecting-values-of-default-and-optional-arguments-of-a-function/40277)

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**Author:** [@colm-connaughton](https://discourse.julialang.org/u/colm-connaughton)\
**Replies:** 0\
**Last updated:** [May 27, 2020, 5:11pm UTC](https://discourse.julialang.org/t/inspecting-values-of-default-and-optional-arguments-of-a-function/40277 "2020-05-27T17:11:07Z")

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Hi everyone. First time poster here. I’m wondering if there is a neat way to access the values of default and optional arguments of a function? Suppose I have julia\> f(x, arg1=10.0, arg2=“Hello world”) = (x, arg1, arg2…

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## [Slowdown with multiple instances per node?](https://discourse.julialang.org/t/slowdown-with-multiple-instances-per-node/40274)

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**Author:** [@sebastian-steiner](https://discourse.julialang.org/u/sebastian-steiner)\
**Replies:** 2\
**Last updated:** [May 27, 2020, 5:20pm UTC](https://discourse.julialang.org/t/slowdown-with-multiple-instances-per-node/40274 "2020-05-27T17:20:17Z")

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I am currently comparing MPI performance between C and Julia and when I only have a single task per node, Julia’s performance is pretty much exactly the same as C’s. But as soon as I utilize all 32 cores on both sockets,…

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## [Behavior of @df inside a function](https://discourse.julialang.org/t/behavior-of-df-inside-a-function/40262)

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**Author:** [@erlebach](https://discourse.julialang.org/u/erlebach)\
**Replies:** 2\
**Last updated:** [May 27, 2020, 5:20pm UTC](https://discourse.julialang.org/t/behavior-of-df-inside-a-function/40262 "2020-05-27T17:20:08Z")

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Consider the function and a call to this function. Notice the placement of @df on the first line of myPlot(). There is a spae before the @df macro. Everything runs fine. However, if I remove this space, then when compi…

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## [For Loop Style Question](https://discourse.julialang.org/t/for-loop-style-question/40271)

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**Author:** [@Nathan\_Boyer](https://discourse.julialang.org/u/Nathan_Boyer)\
**Replies:** 6\
**Last updated:** [May 27, 2020, 4:47pm UTC](https://discourse.julialang.org/t/for-loop-style-question/40271 "2020-05-27T16:47:10Z")

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Given that range1, range2, f(), and g() are set beforehand, what is the preferred way to populate a matrix if we need both indices and values? A=zeros(length(range1),length(range2)) for i in 1:length(range1)-1, j in 1:l…

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## [Help on defining function for ODE solver](https://discourse.julialang.org/t/help-on-defining-function-for-ode-solver/40261)

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**Author:** [@Wenzhe\_Ma](https://discourse.julialang.org/u/Wenzhe_Ma)\
**Replies:** 3\
**Last updated:** [May 27, 2020, 4:02pm UTC](https://discourse.julialang.org/t/help-on-defining-function-for-ode-solver/40261 "2020-05-27T16:02:14Z")

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Newbie here. I am trying to write ODE function with vector calculation in it. And I started with very basic examples. I tried one with expression definition and another with function definition. What puzzles me is that t…

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## [How to convert ODBC.API.SQLGUID to String?](https://discourse.julialang.org/t/how-to-convert-odbc-api-sqlguid-to-string/39636)

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**Author:** [@ryszard314159](https://discourse.julialang.org/u/ryszard314159)\
**Replies:** 1\
**Last updated:** [May 27, 2020, 4:00pm UTC](https://discourse.julialang.org/t/how-to-convert-odbc-api-sqlguid-to-string/39636 "2020-05-27T16:00:32Z")

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Is there a way to convert SQLGUID to String? Apparently there convert() does not have corresponging method. julia\> x ODBC.API.SQLGUID(0x5715b932, 0x4bc5, 0x453c, (0x9d, 0xdb, 0x04, 0xe9, 0x2f, 0x4b, 0x69, 0x87)) julia\>…

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## [Function like VLOOKUP](https://discourse.julialang.org/t/function-like-vlookup/39814)

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**Author:** [@yasser\_rajwani](https://discourse.julialang.org/u/yasser_rajwani)\
**Replies:** 19\
**Last updated:** [May 27, 2020, 3:23pm UTC](https://discourse.julialang.org/t/function-like-vlookup/39814 "2020-05-27T15:23:14Z")

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I have the following data and require a function like Vlookup in excel. Table 1 Criteria 1 Criteria 2 Factor 1 A 1 75 B 2 85 A 2 50…

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## [Split and flatten a field from CSV and use as DataFrame](https://discourse.julialang.org/t/split-and-flatten-a-field-from-csv-and-use-as-dataframe/40217)

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**Author:** [@stej](https://discourse.julialang.org/u/stej)\
**Replies:** 5\
**Last updated:** [May 27, 2020, 2:44pm UTC](https://discourse.julialang.org/t/split-and-flatten-a-field-from-csv-and-use-as-dataframe/40217 "2020-05-27T14:44:09Z")

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Hi all, my MWE is this one with output: julia\> people = DataFrame(name=\["john", "marry", "tim"\], goodat=\["gardening", "teaching,negotiation", ""\]) 3×2 DataFrame │ Row │ name │ goodat │ │ │ String │ …

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## [Passing a wrapped array to a kernel](https://discourse.julialang.org/t/passing-a-wrapped-array-to-a-kernel/40254)

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**Author:** [@emiwar](https://discourse.julialang.org/u/emiwar)\
**Replies:** 2\
**Last updated:** [May 27, 2020, 1:41pm UTC](https://discourse.julialang.org/t/passing-a-wrapped-array-to-a-kernel/40254 "2020-05-27T13:41:57Z")

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Hi, I’m trying to pass an object with a wrapped CuArray to a kernel: import CUDA struct MyStruct arrayField::CUDA.CuArray{Float32, 1, Nothing} end function f!(obj::MyStruct) id = CUDA.threadIdx().x if id \<=…

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## [Help me make this O(n^2) function faster?](https://discourse.julialang.org/t/help-me-make-this-o-n-2-function-faster/24326)

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**Author:** [@evanfields](https://discourse.julialang.org/u/evanfields)\
**Replies:** 8\
**Last updated:** [May 27, 2020, 1:12pm UTC](https://discourse.julialang.org/t/help-me-make-this-o-n-2-function-faster/24326 "2020-05-27T13:12:30Z")

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I have a collection of interval events. Each interval has a (physical) location, a start time, and a stop time. There’s also a non-negative kernel function, e.g. kernel(dist) = ifelse(dist \<= 100, 1, 0). For each interv…

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