# Latest

**URL:** https://discourse.julialang.org/latest.md?page=1760

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

**Page:** 1761

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## [\[ANN-RFC\] NaturalES.jl - Natural Gradient Optimization](https://discourse.julialang.org/t/ann-rfc-naturales-jl-natural-gradient-optimization/38043)

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**Author:** [@francesco.alemanno](https://discourse.julialang.org/u/francesco.alemanno)\
**Replies:** 6\
**Last updated:** [May 1, 2020, 6:34pm UTC](https://discourse.julialang.org/t/ann-rfc-naturales-jl-natural-gradient-optimization/38043 "2020-05-01T18:34:09Z")

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NaturalES.jl This package implements the optimization methods described in Wierstra, et al “Natural Evolution Strategies”, JMLR (2014). this implementation follows the KISS™ principle, it can be used as Usage functi…

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## [Broadcasting trig functions to SparseArrays.SparseMatrixCSC](https://discourse.julialang.org/t/broadcasting-trig-functions-to-sparsearrays-sparsematrixcsc/38570)

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**Author:** [@woochangchung](https://discourse.julialang.org/u/woochangchung)\
**Replies:** 3\
**Last updated:** [May 1, 2020, 6:24pm UTC](https://discourse.julialang.org/t/broadcasting-trig-functions-to-sparsearrays-sparsematrixcsc/38570 "2020-05-01T18:24:52Z")

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I have noticed some difference in behaviors when broadcasting trig functions to SparseArrays.SparseMatrixCSC objects. Here is an example. Let x be a SparseArrays.SparseMatrixCSC{Complex{Float64},Int64} object. It has 1…

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## [Type Float32 has no field data](https://discourse.julialang.org/t/type-float32-has-no-field-data/35397)

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**Author:** [@Eldho.Ashna](https://discourse.julialang.org/u/Eldho.Ashna)\
**Replies:** 4\
**Last updated:** [May 1, 2020, 5:49pm UTC](https://discourse.julialang.org/t/type-float32-has-no-field-data/35397 "2020-05-01T17:49:16Z")

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Hi all, When I ran the following code snippet from JuliaAcademy, using Printf train\_loss = Float64\[\] test\_loss = Float64\[\] function update\_loss!() push!(train\_loss, L(trainbatch...).data) push!(test\_loss, L(tes…

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## [Customize number of stacktraces in REPL](https://discourse.julialang.org/t/customize-number-of-stacktraces-in-repl/38533)

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**Author:** [@Neal](https://discourse.julialang.org/u/Neal)\
**Replies:** 1\
**Last updated:** [May 1, 2020, 4:41pm UTC](https://discourse.julialang.org/t/customize-number-of-stacktraces-in-repl/38533 "2020-05-01T16:41:23Z")

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Hello, I find the number of stacktraces in REPL are a bit overwhelming with my screen get flushed out and my REPL becomes a mess to scroll through history. Most of the time I only need to inspect the the deepest 5 or 10 …

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## [Help with compiler](https://discourse.julialang.org/t/help-with-compiler/38565)

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**Author:** [@tripleo](https://discourse.julialang.org/u/tripleo)\
**Replies:** 0\
**Last updated:** [May 1, 2020, 4:28pm UTC](https://discourse.julialang.org/t/help-with-compiler/38565 "2020-05-01T16:28:26Z")

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Anybody that can help in any way with my compiker is invited to participate:

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## [About type declarations](https://discourse.julialang.org/t/about-type-declarations/38514)

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**Author:** [@rvignolo](https://discourse.julialang.org/u/rvignolo)\
**Replies:** 7\
**Last updated:** [May 1, 2020, 4:10pm UTC](https://discourse.julialang.org/t/about-type-declarations/38514 "2020-05-01T16:10:15Z")

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What is the difference between the following two cases (if there is any difference at all): struct Bar{F} f::F end struct Foo bar::Bar end and: struct Bar{F} f::F end struct Foo{F} bar::Bar{F} end Are both …

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## [Not clear why cumsum! doesn't work in this simple case](https://discourse.julialang.org/t/not-clear-why-cumsum-doesnt-work-in-this-simple-case/38510)

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**Author:** [@lewis](https://discourse.julialang.org/u/lewis)\
**Replies:** 4\
**Last updated:** [May 1, 2020, 3:17pm UTC](https://discourse.julialang.org/t/not-clear-why-cumsum-doesnt-work-in-this-simple-case/38510 "2020-05-01T15:17:07Z")

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The source vector is a column of x and the destination vector is a different column of x. There is nothing in the documentation or source code that says that the base array can’t be the same. Seems to defeat the purpos…

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## [Unsigned long in ccall](https://discourse.julialang.org/t/unsigned-long-in-ccall/38557)

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**Author:** [@mzaffalon](https://discourse.julialang.org/u/mzaffalon)\
**Replies:** 6\
**Last updated:** [May 1, 2020, 2:46pm UTC](https://discourse.julialang.org/t/unsigned-long-in-ccall/38557 "2020-05-01T14:46:16Z")

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I need to call a MPFR library function whose signature is int mpfr\_sub\_ui(mpfr\_t rop, mpfr\_t op1, unsigned long int op2, mpfr\_rnd\_t rnd). The manual says that unsigned long is an Int on Unix and an Int32 on Windows. Is …

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## [How to improve this code](https://discourse.julialang.org/t/how-to-improve-this-code/38535)

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**Author:** [@hmemy](https://discourse.julialang.org/u/hmemy)\
**Replies:** 4\
**Last updated:** [May 1, 2020, 9:35am UTC](https://discourse.julialang.org/t/how-to-improve-this-code/38535 "2020-05-01T09:35:29Z")

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Hi, I have a large number of key dictionaries inside a dictionary named data. I would like to iterate over the collection of dicts to find the bus of type 12, which must be only one in the collection. I came up with th…

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## [How to train a combination of models in Flux?](https://discourse.julialang.org/t/how-to-train-a-combination-of-models-in-flux/38489)

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**Author:** [@DeepQ](https://discourse.julialang.org/u/DeepQ)\
**Replies:** 2\
**Last updated:** [May 1, 2020, 9:29am UTC](https://discourse.julialang.org/t/how-to-train-a-combination-of-models-in-flux/38489 "2020-05-01T09:29:46Z")

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I have two models m1 and m2. Here is my code: using Flux function even\_mask(x) s1, s2 = size(x) weight\_mask = zeros(s1, s2) weight\_mask\[2:2:s1,:\] = ones(Int(s1/2), s2) return weight\_mask end function o…

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## [\[JuMP\] Container Functionality Feature Requests](https://discourse.julialang.org/t/jump-container-functionality-feature-requests/37771)

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**Author:** [@pulsipher](https://discourse.julialang.org/u/pulsipher)\
**Replies:** 10\
**Last updated:** [May 1, 2020, 7:59am UTC](https://discourse.julialang.org/t/jump-container-functionality-feature-requests/37771 "2020-05-01T07:59:46Z")

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I have been using with JuMP’s container types as I am developing my JuMP extension and have two observations that I think would make for 2 relatively simple additions. Observation 1: According to the extension of Base.k…

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## [CSV misbehavior](https://discourse.julialang.org/t/csv-misbehavior/38484)

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**Author:** [@mayar](https://discourse.julialang.org/u/mayar)\
**Replies:** 4\
**Last updated:** [May 1, 2020, 6:11am UTC](https://discourse.julialang.org/t/csv-misbehavior/38484 "2020-05-01T06:11:14Z")

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hello all, I have 2 similar files saved as comma delimited (CSV) I can read only one of them. When I try to read the other one I get this message

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## [Error when compiling C++ code that includes JlCxx](https://discourse.julialang.org/t/error-when-compiling-c-code-that-includes-jlcxx/38526)

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**Author:** [@xiaodai](https://discourse.julialang.org/u/xiaodai)\
**Replies:** 2\
**Last updated:** [May 1, 2020, 4:18am UTC](https://discourse.julialang.org/t/error-when-compiling-c-code-that-includes-jlcxx/38526 "2020-05-01T04:18:46Z")

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I am trying to learn enough C++ so I can leverage the arrow library to write a ParquetWriter. I can compile arrow and I can compile JlCxx, and by following the guides in arrow I can build an application that #include \<a…

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## [Metaprogramming using eval and struct: BUG getting UndefVarError: not defined](https://discourse.julialang.org/t/metaprogramming-using-eval-and-struct-bug-getting-undefvarerror-not-defined/37937)

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**Author:** [@JosephPollacco](https://discourse.julialang.org/u/JosephPollacco)\
**Replies:** 22\
**Last updated:** [May 1, 2020, 3:22am UTC](https://discourse.julialang.org/t/metaprogramming-using-eval-and-struct-bug-getting-undefvarerror-not-defined/37937 "2020-05-01T03:22:04Z")

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I am trying to read parameters from a .csv file for which the name of parameter and its values are given in the .csv file. For that I am trying to simply evaluate a simple expression involving putting the value of the …

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## [Libraries for converting Expr to executable julia codes?](https://discourse.julialang.org/t/libraries-for-converting-expr-to-executable-julia-codes/38521)

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**Author:** [@thautwarm](https://discourse.julialang.org/u/thautwarm)\
**Replies:** 0\
**Last updated:** [May 1, 2020, 2:35am UTC](https://discourse.julialang.org/t/libraries-for-converting-expr-to-executable-julia-codes/38521 "2020-05-01T02:35:35Z")

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I’m trying to lift some uses of macro libraries into develop-only time, in which I have to generate julia codes from Expr. It’s okay even if the conversion is incomplete, I have methods to handle them if some Expr canno…

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## [Show entire matrix](https://discourse.julialang.org/t/show-entire-matrix/1437)

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**Author:** [@cstjean](https://discourse.julialang.org/u/cstjean)\
**Replies:** 8\
**Last updated:** [May 1, 2020, 1:16am UTC](https://discourse.julialang.org/t/show-entire-matrix/1437 "2020-05-01T01:16:07Z")

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I have some narrow but long matrix (dataframe-like), and I’d like it to be displayed entirely in IJulia (or in the REPL). display(m) cuts it in the middle and shows only ~25 rows. show and print show everything, but the …

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## [How to know the elapse time using GLPK solver](https://discourse.julialang.org/t/how-to-know-the-elapse-time-using-glpk-solver/38511)

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**Author:** [@lausilvag](https://discourse.julialang.org/u/lausilvag)\
**Replies:** 1\
**Last updated:** [May 1, 2020, 12:21am UTC](https://discourse.julialang.org/t/how-to-know-the-elapse-time-using-glpk-solver/38511 "2020-05-01T00:21:58Z")

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Hi! I am using the GLPK solver and in the output doesn’t appear the elapsed time: GLPK Simplex Optimizer, v4.64 0: obj = 0.000000000e+000 inf = 3.846e+001 (1) 3: obj = 1.144956706e+007 inf = 0.000e+000 (0) 13: …

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## [Inferring correct environment based on file being run?](https://discourse.julialang.org/t/inferring-correct-environment-based-on-file-being-run/38358)

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**Author:** [@jackf](https://discourse.julialang.org/u/jackf)\
**Replies:** 5\
**Last updated:** [April 30, 2020, 11:45pm UTC](https://discourse.julialang.org/t/inferring-correct-environment-based-on-file-being-run/38358 "2020-04-30T23:45:05Z")

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I have a local package (call it Foo) that I have devd. In the src folder I have a file called main.jl that I’d like to run by calling julia src/main.jl. Currently, I have to call julia --project main.jl to use the correc…

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## [How to call constructor of parametric family of types efficiently](https://discourse.julialang.org/t/how-to-call-constructor-of-parametric-family-of-types-efficiently/38503)

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**Author:** [@SEA](https://discourse.julialang.org/u/SEA)\
**Replies:** 6\
**Last updated:** [April 30, 2020, 8:38pm UTC](https://discourse.julialang.org/t/how-to-call-constructor-of-parametric-family-of-types-efficiently/38503 "2020-04-30T20:38:23Z")

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I would like to call the constructor of several parametric families of types efficiently, while only having access to a concrete instance of a type. Also, I am trying to avoid having to write a separate method for each f…

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## [Develop a local version of a registered package and submit changes as a pull request](https://discourse.julialang.org/t/develop-a-local-version-of-a-registered-package-and-submit-changes-as-a-pull-request/24868)

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**Author:** [@CameronBieganek](https://discourse.julialang.org/u/CameronBieganek)\
**Replies:** 1\
**Last updated:** [April 30, 2020, 7:21pm UTC](https://discourse.julialang.org/t/develop-a-local-version-of-a-registered-package-and-submit-changes-as-a-pull-request/24868 "2020-04-30T19:21:42Z")

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I’ve been working through how one would go about making changes to a registered Julia package and submit the changes as a pull request. I haven’t found one source that explains the whole process, so I thought I’d share w…

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## [Unexpected memory allocation inside ODE function with EnsembleProblem](https://discourse.julialang.org/t/unexpected-memory-allocation-inside-ode-function-with-ensembleproblem/38492)

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**Author:** [@MFairley](https://discourse.julialang.org/u/MFairley)\
**Replies:** 6\
**Last updated:** [April 30, 2020, 7:07pm UTC](https://discourse.julialang.org/t/unexpected-memory-allocation-inside-ode-function-with-ensembleproblem/38492 "2020-04-30T19:07:06Z")

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I am unsure if this is an issue or I just don’t understand how memory allocation works with ensemble problems. I start Julia with --track-allocation=user and run the following small script using DifferentialEquations u…

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## [DataFrames unicode output disable?](https://discourse.julialang.org/t/dataframes-unicode-output-disable/38491)

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**Author:** [@purplishrock](https://discourse.julialang.org/u/purplishrock)\
**Replies:** 6\
**Last updated:** [April 30, 2020, 6:18pm UTC](https://discourse.julialang.org/t/dataframes-unicode-output-disable/38491 "2020-04-30T18:18:47Z")

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I use cygwin for most of my work and as an April fool’s joke, they decided to break unicode output in terminals (interestingly the cygwin shell terminal AND ALL the X-window terminals are broken, meaning it’s a top-level…

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## [How to prevent version upgrade when adding package?](https://discourse.julialang.org/t/how-to-prevent-version-upgrade-when-adding-package/38464)

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**Author:** [@jaynick](https://discourse.julialang.org/u/jaynick)\
**Replies:** 3\
**Last updated:** [April 30, 2020, 5:52pm UTC](https://discourse.julialang.org/t/how-to-prevent-version-upgrade-when-adding-package/38464 "2020-04-30T17:52:14Z")

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In the particular scenario, Flux.jl depends on Zygote.jl, so Pkg.add("Flux") also adds a version of Zygote behind the scene. However, when it is necessary to access something in Zygote, it is still necessary to explic…

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## [Properly connect Julia processes in multiple machines with Sockets](https://discourse.julialang.org/t/properly-connect-julia-processes-in-multiple-machines-with-sockets/38487)

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**Author:** [@martincornejo](https://discourse.julialang.org/u/martincornejo)\
**Replies:** 4\
**Last updated:** [April 30, 2020, 5:00pm UTC](https://discourse.julialang.org/t/properly-connect-julia-processes-in-multiple-machines-with-sockets/38487 "2020-04-30T17:00:34Z")

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Using the Sockets and Serialization libraries, I’m able to connect two Julia processes and exchange data between them. To connect two Julia processes in the same machine I can do the following: Julia process A sckt = a…

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## [Add Julia function within R package without Julia install (or hiding it)](https://discourse.julialang.org/t/add-julia-function-within-r-package-without-julia-install-or-hiding-it/38488)

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**Author:** [@virgile-baudrot](https://discourse.julialang.org/u/virgile-baudrot)\
**Replies:** 2\
**Last updated:** [April 30, 2020, 4:47pm UTC](https://discourse.julialang.org/t/add-julia-function-within-r-package-without-julia-install-or-hiding-it/38488 "2020-04-30T16:47:37Z")

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I would like to provide some simple functions I developed in Julia for R user through an R package. With JuliaCall, it should be easy, but I have some difficulties to make a link between Julia objects and functions in th…

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## [Why Julia? - A Call For Community Video Testimonials](https://discourse.julialang.org/t/why-julia-a-call-for-community-video-testimonials/37916)

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**Author:** [@logankilpatrick](https://discourse.julialang.org/u/logankilpatrick)\
**Replies:** 6\
**Last updated:** [April 30, 2020, 4:40pm UTC](https://discourse.julialang.org/t/why-julia-a-call-for-community-video-testimonials/37916 "2020-04-30T16:40:47Z")

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Hey all, Some of the folks in the #community channel on Slack had an interesting idea of highlighting some of the reasons we all have chosen to use Julia. One possible way to do this is by creating a playlist on the Jul…

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## [SQLite/DBInterface confusion](https://discourse.julialang.org/t/sqlite-dbinterface-confusion/38458)

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**Author:** [@purplishrock](https://discourse.julialang.org/u/purplishrock)\
**Replies:** 5\
**Last updated:** [April 30, 2020, 4:37pm UTC](https://discourse.julialang.org/t/sqlite-dbinterface-confusion/38458 "2020-04-30T16:37:43Z")

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Looks like something’s changed since i last used it. I went to the doc’s and saw this, DBInterface.execute(db::SQLite.DB, sql::String, \[params\]) huh. i don’t remember DBInterface… ok, installed it, then tried: db…

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## [How do modify marker thickness in Plots.jl?](https://discourse.julialang.org/t/how-do-modify-marker-thickness-in-plots-jl/38437)

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**Author:** [@ssfrr](https://discourse.julialang.org/u/ssfrr)\
**Replies:** 1\
**Last updated:** [April 30, 2020, 2:42pm UTC](https://discourse.julialang.org/t/how-do-modify-marker-thickness-in-plots-jl/38437 "2020-04-30T14:42:42Z")

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Is there a way to change the thickness of the line-type markers (e.g. :xcross and :cross) in Plots.jl? I’m using the GR backend, if it matters. I’d expect the following to give a marker with pretty thick lines, but neit…

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## [Need help finishing a groupby random sampling function](https://discourse.julialang.org/t/need-help-finishing-a-groupby-random-sampling-function/38485)

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**Author:** [@Julia1](https://discourse.julialang.org/u/Julia1)\
**Replies:** 0\
**Last updated:** [April 30, 2020, 1:58pm UTC](https://discourse.julialang.org/t/need-help-finishing-a-groupby-random-sampling-function/38485 "2020-04-30T13:58:41Z")

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Hi how’s it going, I have a function that takes in a dataframe, groups by a column, and takes a random sample of that column. I want to set some condition that says “If the size of this subdataframe is less than 20, don’…

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## [Interpreting compatibility errors Pkg add](https://discourse.julialang.org/t/interpreting-compatibility-errors-pkg-add/38480)

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**Author:** [@Torkel](https://discourse.julialang.org/u/Torkel)\
**Replies:** 3\
**Last updated:** [April 30, 2020, 1:49pm UTC](https://discourse.julialang.org/t/interpreting-compatibility-errors-pkg-add/38480 "2020-04-30T13:49:48Z")

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Yes, this is a similar issue to, Interpreting Pkg add errors), which have already been reported. But it never got any answer, so I will ask again (and possibly suggest more things added to the documentation). It has happ…

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