# Latest

**URL:** https://discourse.julialang.org/latest.md?page=1971

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

**Page:** 1972

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## [JuliaCon program sneak peek](https://discourse.julialang.org/t/juliacon-program-sneak-peek/25610)

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**Author:** [@vchuravy](https://discourse.julialang.org/u/vchuravy)\
**Replies:** 2\
**Last updated:** [June 26, 2019, 12:58pm UTC](https://discourse.julialang.org/t/juliacon-program-sneak-peek/25610 "2019-06-26T12:58:04Z")

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Hello! The JuliaCon program sneak-peek is available at https://pretalx.com/juliacon2019/sneak/! Best, Valentin

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## [Error in variable define](https://discourse.julialang.org/t/error-in-variable-define/25717)

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**Author:** [@ahmedbulbul52](https://discourse.julialang.org/u/ahmedbulbul52)\
**Replies:** 5\
**Last updated:** [June 26, 2019, 12:52pm UTC](https://discourse.julialang.org/t/error-in-variable-define/25717 "2019-06-26T12:52:14Z")

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ERROR: UndefVarError: view not defined in partboost at /home//Desktop/test.jl:75 in findpartition at /home/Desktop/test.jl:200 Kindly suggest how to solve this problem, I’m new in this programming.

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## [1e6+ constrained optimization problems](https://discourse.julialang.org/t/1e6-constrained-optimization-problems/22032)

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**Author:** [@jcreinhold](https://discourse.julialang.org/u/jcreinhold)\
**Replies:** 17\
**Last updated:** [June 26, 2019, 10:49am UTC](https://discourse.julialang.org/t/1e6-constrained-optimization-problems/22032 "2019-06-26T10:49:22Z")

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I am working on a problem in medical imaging where I have to solve an optimization problem at every voxel (read: pixel) that is not background. The optimization problem is relatively simple, it is a system of three non-l…

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## [Julia and Concurrency](https://discourse.julialang.org/t/julia-and-concurrency/25556)

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**Author:** [@fraxx001](https://discourse.julialang.org/u/fraxx001)\
**Replies:** 6\
**Last updated:** [June 26, 2019, 9:42am UTC](https://discourse.julialang.org/t/julia-and-concurrency/25556 "2019-06-26T09:42:23Z")

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Hi, iam a bit curious about the plans for concurrency in Julia. As far as I understand the documentation, there is no real and easy support for Multithreading atm. The Task API provides an Interface for batch execution …

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## [Loading a module outside \`Main\` module](https://discourse.julialang.org/t/loading-a-module-outside-main-module/15282)

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**Author:** [@ahmetumutdurmus](https://discourse.julialang.org/u/ahmetumutdurmus)\
**Replies:** 5\
**Last updated:** [June 26, 2019, 7:36am UTC](https://discourse.julialang.org/t/loading-a-module-outside-main-module/15282 "2019-06-26T07:36:25Z")

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Hi, I am currently trying to create a module and load it back again for further use yet having trouble in doing so. Consider the trivial example: module MyModule export x, y x() = "x" y() = "y" p() = "p" end using …

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## [Surprised that broadcast does not use views?](https://discourse.julialang.org/t/surprised-that-broadcast-does-not-use-views/25662)

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**Author:** [@Krastanov](https://discourse.julialang.org/u/Krastanov)\
**Replies:** 8\
**Last updated:** [June 26, 2019, 7:35am UTC](https://discourse.julialang.org/t/surprised-that-broadcast-does-not-use-views/25662 "2019-06-26T07:35:44Z")

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I am using a simple broadcast expression, and getting a surprising (to me) result depending on whether I use views or not. #setup a = rand(UInt64, 1000, 1000) b = rand(UInt64, 1000, 1000) c = rand(UInt64, 1000); Doing …

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## [Weird colorbar](https://discourse.julialang.org/t/weird-colorbar/25670)

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**Author:** [@wiktorkujawa](https://discourse.julialang.org/u/wiktorkujawa)\
**Replies:** 0\
**Last updated:** [June 25, 2019, 10:56pm UTC](https://discourse.julialang.org/t/weird-colorbar/25670 "2019-06-25T22:56:14Z")

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I generated some plots and wanted to add colorbar to them and it partially works. My code to generate this bar in CImGui is: low=colorant"navyblue"; medium=colorant"limegreen"; high=colorant"yellow"; barImage=Array{R…

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## [Minimise() in IntervalOptimisation does not accept keyword arguments](https://discourse.julialang.org/t/minimise-in-intervaloptimisation-does-not-accept-keyword-arguments/25678)

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**Author:** [@bocc](https://discourse.julialang.org/u/bocc)\
**Replies:** 3\
**Last updated:** [June 26, 2019, 6:47am UTC](https://discourse.julialang.org/t/minimise-in-intervaloptimisation-does-not-accept-keyword-arguments/25678 "2019-06-26T06:47:41Z")

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Hello All, I am experimenting a bit with IntervalOptimisation package, and I have run into a problem (I am a Julia noob, please excuse me if the resolution is trivial - I’ve tried to find the answer by myself but couldn…

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## [Dealing with images in PDF display from Weave.jl](https://discourse.julialang.org/t/dealing-with-images-in-pdf-display-from-weave-jl/25419)

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**Author:** [@ssfrr](https://discourse.julialang.org/u/ssfrr)\
**Replies:** 2\
**Last updated:** [June 26, 2019, 5:41am UTC](https://discourse.julialang.org/t/dealing-with-images-in-pdf-display-from-weave-jl/25419 "2019-06-26T05:41:18Z")

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I’m using Weave.jl to write up a report using .jmd format. I need to include some images that I’ve already generated, so I included them in my markdown as I normally would: !\[a descriptive caption\](one pair random data.…

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## [Dispatching on the result of unwrap\_unionall seems weird?](https://discourse.julialang.org/t/dispatching-on-the-result-of-unwrap-unionall-seems-weird/25677)

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**Author:** [@marius311](https://discourse.julialang.org/u/marius311)\
**Replies:** 0\
**Last updated:** [June 26, 2019, 5:31am UTC](https://discourse.julialang.org/t/dispatching-on-the-result-of-unwrap-unionall-seems-weird/25677 "2019-06-26T05:31:22Z")

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I’m pretty confused about the following dispatch behavior (Julia 1.1 and 1.2pre): julia\> foo(::Type{V}) where {V\<:Vector} = @isdefined(V) foo (generic function with 1 method) julia\> foo(Base.unwrap\_unionall(Vector)) fa…

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## [Customize serialization on fetch from worker](https://discourse.julialang.org/t/customize-serialization-on-fetch-from-worker/25637)

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**Author:** [@felipenoris](https://discourse.julialang.org/u/felipenoris)\
**Replies:** 6\
**Last updated:** [June 26, 2019, 2:01am UTC](https://discourse.julialang.org/t/customize-serialization-on-fetch-from-worker/25637 "2019-06-26T02:01:19Z")

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I’m working on Mongoc.jl and I would like to make BSON documents serializable between julia workers. mutable struct BSON handle::Ptr{Cvoid} end Since Mongoc.BSON is just a wrapper for a C handle, if I just fetch th…

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## [UndefVarError for some variables](https://discourse.julialang.org/t/undefvarerror-for-some-variables/25660)

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**Author:** [@brunaw](https://discourse.julialang.org/u/brunaw)\
**Replies:** 4\
**Last updated:** [June 25, 2019, 10:49pm UTC](https://discourse.julialang.org/t/undefvarerror-for-some-variables/25660 "2019-06-25T22:49:53Z")

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Hey all. I’ve been trying to write some functions in Julia, but I’ve been getting many errors of the UndefVarError: variable not defined type. The main source of the errors is this part here (which is inside my functio…

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## [Very basic Flux problem](https://discourse.julialang.org/t/very-basic-flux-problem/25663)

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**Author:** [@austinbean](https://discourse.julialang.org/u/austinbean)\
**Replies:** 1\
**Last updated:** [June 25, 2019, 7:23pm UTC](https://discourse.julialang.org/t/very-basic-flux-problem/25663 "2019-06-25T19:23:24Z")

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I’m starting to use flux for an NN task, but I’m having trouble understanding an error message. The following is not my use case, but maybe if I understand what’s going wrong here I can fix my actual problem… using Fl…

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## [X::Vector{Union{Missing, Any}}](https://discourse.julialang.org/t/x-vector-union-missing-any/14896)

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**Author:** [@DominiqueMakowski](https://discourse.julialang.org/u/DominiqueMakowski)\
**Replies:** 12\
**Last updated:** [June 25, 2019, 6:56pm UTC](https://discourse.julialang.org/t/x-vector-union-missing-any/14896 "2019-06-25T18:56:19Z")

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I am trying to write a function that would work for any vector containing missings. However, it seems that f(X::Vector{Union{Missing, Any}}) = print("hi") doesn’t work. Could someone enlight me on how to build function…

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## [Error on incompatibility of matrix multiplications](https://discourse.julialang.org/t/error-on-incompatibility-of-matrix-multiplications/25486)

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**Author:** [@ahmadreza-marandi](https://discourse.julialang.org/u/ahmadreza-marandi)\
**Replies:** 4\
**Last updated:** [June 25, 2019, 5:49pm UTC](https://discourse.julialang.org/t/error-on-incompatibility-of-matrix-multiplications/25486 "2019-06-25T17:49:22Z")

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I wrote a code where I have many matrix multiplications. While running the code after opening Julia1.0.4, I got an error that the matrix sizes are incompatible. However, when I ran the code for the second time, the error…

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## [How does the impending ubuntugeddon affect the Julia community](https://discourse.julialang.org/t/how-does-the-impending-ubuntugeddon-affect-the-julia-community/25616)

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**Author:** [@ExpandingMan](https://discourse.julialang.org/u/ExpandingMan)\
**Replies:** 15\
**Last updated:** [June 25, 2019, 5:02pm UTC](https://discourse.julialang.org/t/how-does-the-impending-ubuntugeddon-affect-the-julia-community/25616 "2019-06-25T17:02:17Z")

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Probably not directly, as even the official Julia docker is on Debian, but I’m just kind of curious about everyone’s mood on this subject. For those not aware, Ubuntu is “dropping 32 bit support” (not necessarily the be…

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## [IJulia & RISE presentation to PDF](https://discourse.julialang.org/t/ijulia-rise-presentation-to-pdf/25599)

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**Author:** [@nantonel](https://discourse.julialang.org/u/nantonel)\
**Replies:** 3\
**Last updated:** [June 25, 2019, 4:12pm UTC](https://discourse.julialang.org/t/ijulia-rise-presentation-to-pdf/25599 "2019-06-25T16:12:30Z")

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Hi all, does anyone know the procedure to generate a pdf out of a presentation made with RISE? I’m using Julia 1.1 and IJulia. I’ve installed rise with Conda.jl using the following command: Conda.add("rise") Looking …

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## [Non-allocating loop over a set of structs](https://discourse.julialang.org/t/non-allocating-loop-over-a-set-of-structs/25643)

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**Author:** [@fedoroff](https://discourse.julialang.org/u/fedoroff)\
**Replies:** 13\
**Last updated:** [June 25, 2019, 3:22pm UTC](https://discourse.julialang.org/t/non-allocating-loop-over-a-set-of-structs/25643 "2019-06-25T15:22:42Z")

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I have a set of structs and I want to loop over them. The following code shows two possible loops together with a sequential one by one access to structs: using BenchmarkTools struct Sample{T\<:AbstractFloat, F\<:Functio…

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## [Flux.jl is not modifying the loss](https://discourse.julialang.org/t/flux-jl-is-not-modifying-the-loss/25646)

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**Author:** [@francesco.alemanno](https://discourse.julialang.org/u/francesco.alemanno)\
**Replies:** 4\
**Last updated:** [June 25, 2019, 3:05pm UTC](https://discourse.julialang.org/t/flux-jl-is-not-modifying-the-loss/25646 "2019-06-25T15:05:46Z")

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using Flux,LinearAlgebra function MWE() η=0.01 model=Conv((64, 64), 1=\>1, relu,stride=30) loss(x,y) = Flux.mse(model(x),y) dataset=\[(rand(100,100,1,1),rand(2,2,1,1))\] @show model(dataset\[1\]\[1\]) @s…

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## [Latex character display issue](https://discourse.julialang.org/t/latex-character-display-issue/25628)

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**Author:** [@pmeiners](https://discourse.julialang.org/u/pmeiners)\
**Replies:** 3\
**Last updated:** [June 25, 2019, 2:19pm UTC](https://discourse.julialang.org/t/latex-character-display-issue/25628 "2019-06-25T14:19:43Z")

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Hey, I’m having issues with some Latex characters in the Julia Command line. The tab completion of α, β, π etc. works fine, but \\euler (ℯ) and \\sinewave (∿) for example produce an empty square. Julia does understand the…

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## [Question about JLD2 save/load of RData nested list](https://discourse.julialang.org/t/question-about-jld2-save-load-of-rdata-nested-list/25649)

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**Author:** [@floswald](https://discourse.julialang.org/u/floswald)\
**Replies:** 3\
**Last updated:** [June 25, 2019, 1:14pm UTC](https://discourse.julialang.org/t/question-about-jld2-save-load-of-rdata-nested-list/25649 "2019-06-25T13:14:20Z")

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suppose i have this module jldtest using DataFrames using JLD2, FileIO using RData using RCall # make some R data R""" rdata \<- list(a = runif(3), b = letters\[1:3\]) save(rdata, file = 'rr.RData') """ d = D…

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## [What is a .jtexw file?](https://discourse.julialang.org/t/what-is-a-jtexw-file/25647)

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**Author:** [@kapple](https://discourse.julialang.org/u/kapple)\
**Replies:** 1\
**Last updated:** [June 25, 2019, 12:53pm UTC](https://discourse.julialang.org/t/what-is-a-jtexw-file/25647 "2019-06-25T12:53:15Z")

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The Atom package language-weave claims to support the following files: Weave.jl: markdown for .jmd, .mdw and .jmdw (markdown with noweb) Weave.jl: LaTex for texw, .jtexw and .jnw. Weave.jl: reStructuredText for .…

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## [Bounds in function arguments](https://discourse.julialang.org/t/bounds-in-function-arguments/25635)

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**Author:** [@fipelle](https://discourse.julialang.org/u/fipelle)\
**Replies:** 4\
**Last updated:** [June 25, 2019, 10:55am UTC](https://discourse.julialang.org/t/bounds-in-function-arguments/25635 "2019-06-25T10:55:00Z")

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Hi, I am writing down a set of functions, and I want to make sure that some of the arguments are bounded within some given values. For the sake of simplicity, say that I only have the following function: function my\_f…

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## [PackageCompiler dependency issues (1.1; failing with dependency errors)](https://discourse.julialang.org/t/packagecompiler-dependency-issues-1-1-failing-with-dependency-errors/25578)

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**Author:** [@srs](https://discourse.julialang.org/u/srs)\
**Replies:** 5\
**Last updated:** [June 24, 2019, 6:10pm UTC](https://discourse.julialang.org/t/packagecompiler-dependency-issues-1-1-failing-with-dependency-errors/25578 "2019-06-24T18:10:47Z")

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What is the correct way to use PackageCompiler in 1.1? I naively tried: using PackageCompiler compile\_incremental(:Plots, force=false) And it keeps throwing dependency errors, like: “LoadError: … Package … is required…

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## [Asynchronous variable change](https://discourse.julialang.org/t/asynchronous-variable-change/25441)

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**Author:** [@KestutisMa](https://discourse.julialang.org/u/KestutisMa)\
**Replies:** 2\
**Last updated:** [June 25, 2019, 9:35am UTC](https://discourse.julialang.org/t/asynchronous-variable-change/25441 "2019-06-25T09:35:07Z")

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Hi, I am implementing biophysical simulation software with GUI using Blink.jl and js that controls Julia part of code. I want to be able to start at stop Julia algorithm at any iteration from GUI. I considered idea about…

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## [How to specify parametric type in function argument?](https://discourse.julialang.org/t/how-to-specify-parametric-type-in-function-argument/25641)

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**Author:** [@tomtom](https://discourse.julialang.org/u/tomtom)\
**Replies:** 2\
**Last updated:** [June 25, 2019, 8:20am UTC](https://discourse.julialang.org/t/how-to-specify-parametric-type-in-function-argument/25641 "2019-06-25T08:20:10Z")

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let’s say I have a parametric type like: struct Param{T \<: AbstractFloat} value::T end julia\> p1 = Param(3.0) Param{Float64}(3.0) julia\> p2 = Param(BigFloat(5.0) ) Param{BigFloat}(5.0) how could I “tie” the type …

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## [Julia gift store](https://discourse.julialang.org/t/julia-gift-store/25428)

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**Author:** [@avik](https://discourse.julialang.org/u/avik)\
**Replies:** 8\
**Last updated:** [June 25, 2019, 7:04am UTC](https://discourse.julialang.org/t/julia-gift-store/25428 "2019-06-25T07:04:30Z")

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We have relaunched the Julia swag store at a new location, with some new products. Please visit JuliaLang Many of the new designs have been created by the amazing @cormullion. A huge amount of thanks and kudos to him. I…

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## [Insert into postgres from array of dictionaries](https://discourse.julialang.org/t/insert-into-postgres-from-array-of-dictionaries/25563)

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**Author:** [@jonjilla](https://discourse.julialang.org/u/jonjilla)\
**Replies:** 4\
**Last updated:** [June 25, 2019, 4:29am UTC](https://discourse.julialang.org/t/insert-into-postgres-from-array-of-dictionaries/25563 "2019-06-25T04:29:01Z")

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I’m trying to use LibPQ to insert data into a Postgres database. I have the data as an array of dictionaries. I’m trying to figure out the correct way to insert this but the documentation and examples are a little bit …

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## [Add and develope an unregistered local package](https://discourse.julialang.org/t/add-and-develope-an-unregistered-local-package/25632)

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**Author:** [@Amin\_Yahyaabadi](https://discourse.julialang.org/u/Amin_Yahyaabadi)\
**Replies:** 1\
**Last updated:** [June 25, 2019, 3:22am UTC](https://discourse.julialang.org/t/add-and-develope-an-unregistered-local-package/25632 "2019-06-25T03:22:34Z")

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I am trying to update a discontinued package called MatlabCompat.jl. First, I ran my forked FemtoCleaner locally to update the deprecated syntax, and here is the result: Updated MatlabCompat.jl. However, as I mentione…

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## [How to dynamically add/build optional dependencies to improve user experience for our package?](https://discourse.julialang.org/t/how-to-dynamically-add-build-optional-dependencies-to-improve-user-experience-for-our-package/25605)

<div class="topic-metadata">

**Author:** [@PolarizedPoutine](https://discourse.julialang.org/u/PolarizedPoutine)\
**Replies:** 4\
**Last updated:** [June 25, 2019, 12:55am UTC](https://discourse.julialang.org/t/how-to-dynamically-add-build-optional-dependencies-to-improve-user-experience-for-our-package/25605 "2019-06-25T00:55:27Z")

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I’m working on an ocean model with multiple large dependencies for optional features: CUDAnative.jl, CuArrays.jl for GPU support. HDF5.jl and NetCDF.jl if users want output in NetCDF format. MPI.jl for distributed supp…

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