# Latest

**URL:** https://discourse.julialang.org/latest.md?page=1609

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

**Page:** 1610

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## [Enum versus abstract typing](https://discourse.julialang.org/t/enum-versus-abstract-typing/47941)

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**Author:** [@davide-f](https://discourse.julialang.org/u/davide-f)\
**Replies:** 8\
**Last updated:** [October 7, 2020, 5:31pm UTC](https://discourse.julialang.org/t/enum-versus-abstract-typing/47941 "2020-10-07T17:31:22Z")

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Hi, I am developing a code aiming at a good balance between speed, resources and generalizability. In my original code that was using only concrete assets, mainly, the code was relatively fast, about 68ms. Aiming to ge…

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## [Obscure multiplication method error when using sciml\_train](https://discourse.julialang.org/t/obscure-multiplication-method-error-when-using-sciml-train/45906)

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**Author:** [@told](https://discourse.julialang.org/u/told)\
**Replies:** 7\
**Last updated:** [October 7, 2020, 5:28pm UTC](https://discourse.julialang.org/t/obscure-multiplication-method-error-when-using-sciml-train/45906 "2020-10-07T17:28:26Z")

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Julia newbie here. I solve a convection diffusion reaction problem in tow variables where the reaction term is replaced with an ANN with two inputs and one output. This should be trained against measured data c\_true. D…

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## [Feature request and Brainstorming , global let (issue #37187)](https://discourse.julialang.org/t/feature-request-and-brainstorming-global-let-issue-37187/47837)

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**Author:** [@systems](https://discourse.julialang.org/u/systems)\
**Replies:** 20\
**Last updated:** [October 7, 2020, 5:02pm UTC](https://discourse.julialang.org/t/feature-request-and-brainstorming-global-let-issue-37187/47837 "2020-10-07T17:02:29Z")

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This is a feature request proposal Brain Storming The proposal (initially) add construct global let to julia global let ... end Scripts (without) module declaration should assume being inside a global let ad…

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## [What are the plans for \`x.\[1\]\`?](https://discourse.julialang.org/t/what-are-the-plans-for-x-1/47945)

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**Author:** [@pdeffebach](https://discourse.julialang.org/u/pdeffebach)\
**Replies:** 3\
**Last updated:** [October 7, 2020, 4:54pm UTC](https://discourse.julialang.org/t/what-are-the-plans-for-x-1/47945 "2020-10-07T16:54:17Z")

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I think this came up a while ago but it’s a hard thing to search for. Are there any plans in the language for x.\[1\] as an alias for getindex.(x, 1)?

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## [How do I throw an Exception with a given backtrace?](https://discourse.julialang.org/t/how-do-i-throw-an-exception-with-a-given-backtrace/47940)

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**Author:** [@oxinabox](https://discourse.julialang.org/u/oxinabox)\
**Replies:** 3\
**Last updated:** [October 7, 2020, 4:33pm UTC](https://discourse.julialang.org/t/how-do-i-throw-an-exception-with-a-given-backtrace/47940 "2020-10-07T16:33:21Z")

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If I have aquired a backtrace, e.g. from backtrace() and i want to throw an exception that impersonates an exception being thrown with that backtrace, how do i do it?

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## [Gnuplot.jl hangs on first run](https://discourse.julialang.org/t/gnuplot-jl-hangs-on-first-run/47946)

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**Author:** [@affans](https://discourse.julialang.org/u/affans)\
**Replies:** 0\
**Last updated:** [October 7, 2020, 4:29pm UTC](https://discourse.julialang.org/t/gnuplot-jl-hangs-on-first-run/47946 "2020-10-07T16:29:58Z")

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I am really beginning to like gnuplot and switching over from R’s ggplot (although I still think ggplot might be more flexible and powerful). Anyways, I have a slight problem in the Julia wrapper Gnuplot.jl. It seems tha…

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## [Plots -- xlims with x axis given by dates?](https://discourse.julialang.org/t/plots-xlims-with-x-axis-given-by-dates/47926)

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**Author:** [@BLI](https://discourse.julialang.org/u/BLI)\
**Replies:** 6\
**Last updated:** [October 7, 2020, 3:38pm UTC](https://discourse.julialang.org/t/plots-xlims-with-x-axis-given-by-dates/47926 "2020-10-07T15:38:34Z")

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I’m plotting some data as a function of date, e.g., plot(date\_vector, data\_vector). I produce several plots with different pairs of date\_vector and data\_vector. So I’d like to use the same xlims in all plots. Specifying…

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## [Button doesn't do anything in Pluto](https://discourse.julialang.org/t/button-doesnt-do-anything-in-pluto/46381)

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**Author:** [@Daneel](https://discourse.julialang.org/u/Daneel)\
**Replies:** 7\
**Last updated:** [October 7, 2020, 3:50pm UTC](https://discourse.julialang.org/t/button-doesnt-do-anything-in-pluto/46381 "2020-10-07T15:50:08Z")

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I’m trying to create a simple plotting interface in Pluto.jl but because of the slowness of loading data I need to prevent Pluto from plotting until all of the settings are chosen. The button seemed like a good method bu…

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## [TextAnalysis.jl statistical language models not defined](https://discourse.julialang.org/t/textanalysis-jl-statistical-language-models-not-defined/47928)

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**Author:** [@Fenmore](https://discourse.julialang.org/u/Fenmore)\
**Replies:** 3\
**Last updated:** [October 7, 2020, 2:15pm UTC](https://discourse.julialang.org/t/textanalysis-jl-statistical-language-models-not-defined/47928 "2020-10-07T14:15:09Z")

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Hello, I am quite new here, hopefully I didn’t miss something. I would like to use the TextAnalysis package for some language modeling like explained here Statistical Language Model - TextAnalysis My TextAnalysis vers…

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## [Using the noise parameters sol.W.W from an SDE solution throws an error when taking gradients](https://discourse.julialang.org/t/using-the-noise-parameters-sol-w-w-from-an-sde-solution-throws-an-error-when-taking-gradients/47640)

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**Author:** [@MikeKlocCZ](https://discourse.julialang.org/u/MikeKlocCZ)\
**Replies:** 3\
**Last updated:** [October 7, 2020, 2:13pm UTC](https://discourse.julialang.org/t/using-the-noise-parameters-sol-w-w-from-an-sde-solution-throws-an-error-when-taking-gradients/47640 "2020-10-07T14:13:03Z")

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I need to work with individual Wiener increments from an SDE solution in my loss function. Whenever I try to get these values from sol.W.W command, the ERROR: type Nothing has no field W pops up when computing the gradie…

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## [Simple web app controls LEDs connected to an RPI](https://discourse.julialang.org/t/simple-web-app-controls-leds-connected-to-an-rpi/34896)

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**Author:** [@yakir12](https://discourse.julialang.org/u/yakir12)\
**Replies:** 15\
**Last updated:** [October 7, 2020, 1:35pm UTC](https://discourse.julialang.org/t/simple-web-app-controls-leds-connected-to-an-rpi/34896 "2020-10-07T13:35:03Z")

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I want a user to browse to a website, move one radio button and one slider, and a Raspberry Pi which is listening to that website will control a few LED strips connected to it depending on the user’s choices (the whole s…

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## [How to plot circles with given radii using Plots](https://discourse.julialang.org/t/how-to-plot-circles-with-given-radii-using-plots/47845)

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**Author:** [@SteffenPL](https://discourse.julialang.org/u/SteffenPL)\
**Replies:** 12\
**Last updated:** [October 7, 2020, 12:46pm UTC](https://discourse.julialang.org/t/how-to-plot-circles-with-given-radii-using-plots/47845 "2020-10-07T12:46:12Z")

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I want to create movies of biological cells which are represented as circles. My main problem is speed. Generating the videos I need takes more than 10 minutes. Currently, I am using this approach to plot circles How…

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## [Is it documented anywhere that I can create an array like this?](https://discourse.julialang.org/t/is-it-documented-anywhere-that-i-can-create-an-array-like-this/47909)

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**Author:** [@anon60034542](https://discourse.julialang.org/u/anon60034542)\
**Replies:** 4\
**Last updated:** [October 7, 2020, 12:25pm UTC](https://discourse.julialang.org/t/is-it-documented-anywhere-that-i-can-create-an-array-like-this/47909 "2020-10-07T12:25:55Z")

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I was reading about Array initialization, and it talks about using the undef keyword for an uninitialized array. However, if you leave out the undef keyword and pass an iterable, you can create an array, for example: nu…

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## [Resize! and multidimensional arrays](https://discourse.julialang.org/t/resize-and-multidimensional-arrays/47842)

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**Author:** [@ranocha](https://discourse.julialang.org/u/ranocha)\
**Replies:** 4\
**Last updated:** [October 7, 2020, 9:37am UTC](https://discourse.julialang.org/t/resize-and-multidimensional-arrays/47842 "2020-10-07T09:37:44Z")

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Background We want to make use of adaptive mesh refinement (AMR) for our hyperbolic PDE solver package Trixi.jl. For us, the most natural data layout is given by multidimensional arrays. To use AMR, we need to resize! th…

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## [Disable artifacts default download location?](https://discourse.julialang.org/t/disable-artifacts-default-download-location/47791)

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**Author:** [@DrChainsaw](https://discourse.julialang.org/u/DrChainsaw)\
**Replies:** 4\
**Last updated:** [October 7, 2020, 8:33am UTC](https://discourse.julialang.org/t/disable-artifacts-default-download-location/47791 "2020-10-07T08:33:07Z")

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Hi, I have an Artifacts.toml with the following vanilla tarball artifact: \[artifactX\] git-tree-sha1 = \<generated through create\_artifact(d -\> path\_to\_manually\_downloaded\_tarball, artifact\_toml) \> lazy = true \[\[art…

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## [Nested macros and esc](https://discourse.julialang.org/t/nested-macros-and-esc/47857)

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**Author:** [@johnmyleswhite](https://discourse.julialang.org/u/johnmyleswhite)\
**Replies:** 18\
**Last updated:** [October 7, 2020, 8:10am UTC](https://discourse.julialang.org/t/nested-macros-and-esc/47857 "2020-10-07T08:10:33Z")

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I have an example of nesting macros that makes me think I’m confused about how hygiene works. Here’s a minimal example: macro inner(e) println("In @inner") dump(e) @assert isa(e, Expr) && e.head == :$ e…

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## [Compiling a project specific sysimage](https://discourse.julialang.org/t/compiling-a-project-specific-sysimage/47902)

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**Author:** [@martenlienen](https://discourse.julialang.org/u/martenlienen)\
**Replies:** 2\
**Last updated:** [October 7, 2020, 7:42am UTC](https://discourse.julialang.org/t/compiling-a-project-specific-sysimage/47902 "2020-10-07T07:42:49Z")

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I am getting started with Julia and having a good time. One thing I dislike quite a bit though is the slow startup time of a REPL when you import some costly packages in the beginning. As far as I can tell the best way t…

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## [Least common multiple function description in the "help" environment](https://discourse.julialang.org/t/least-common-multiple-function-description-in-the-help-environment/47887)

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**Author:** [@fdamore](https://discourse.julialang.org/u/fdamore)\
**Replies:** 2\
**Last updated:** [October 7, 2020, 7:42am UTC](https://discourse.julialang.org/t/least-common-multiple-function-description-in-the-help-environment/47887 "2020-10-07T07:42:05Z")

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Hi everybody. I am sorry if this is the inappropriate category, but I’m new to the forum (and to Julia) and I did not find any other fitting category. I was looking for the simple least common multiple function “lcm()”…

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## [How to filter out Dict based on the value of subdict](https://discourse.julialang.org/t/how-to-filter-out-dict-based-on-the-value-of-subdict/47914)

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**Author:** [@sogrbilja](https://discourse.julialang.org/u/sogrbilja)\
**Replies:** 1\
**Last updated:** [October 7, 2020, 7:35am UTC](https://discourse.julialang.org/t/how-to-filter-out-dict-based-on-the-value-of-subdict/47914 "2020-10-07T07:35:16Z")

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I have a Dict: UNITS = Dict(\[ "BUHLER2" =\> Dict(\["cap" =\> 2000, "mincap" =\> 60, "dcap" =\> 49660, "util\_cost1" =\> 2, "maxprodr" =\> 49660\]), "BUHLER1" =\> Dict(\["cap" =\> 1500, "mincap" =\> 60, "dcap" =\> 37245, "u…

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## [Why don't we have: Base.broadcastable(task::Task) = Ref(task)?](https://discourse.julialang.org/t/why-dont-we-have-base-broadcastable-task-task-ref-task/47889)

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**Author:** [@nielsls](https://discourse.julialang.org/u/nielsls)\
**Replies:** 2\
**Last updated:** [October 7, 2020, 6:47am UTC](https://discourse.julialang.org/t/why-dont-we-have-base-broadcastable-task-task-ref-task/47889 "2020-10-07T06:47:17Z")

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Is there any reason why Task is not made broadcastable using: Base.broadcastable(task::Task) = Ref(task) Currently, the below line fails if task\_collection is a single Task (scalar): x = fetch.(task\_collection)

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## [Gadfly label coloring](https://discourse.julialang.org/t/gadfly-label-coloring/37374)

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**Author:** [@monty](https://discourse.julialang.org/u/monty)\
**Replies:** 2\
**Last updated:** [October 7, 2020, 4:46am UTC](https://discourse.julialang.org/t/gadfly-label-coloring/37374 "2020-10-07T04:46:21Z")

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How to color the labels with the color of the dots? Gadfly.plot(\[1 2 "a";3 4 "b"; 3 2 "c"\], x=Gadfly.Col.value(1), y=Gadfly.Col.value(2), label=Gadfly.Col.value(3), color=Gadfly.Col.value(3), Gadfly.Geom.point, Gadfly.G…

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## [Re Pluto, results appear above entries](https://discourse.julialang.org/t/re-pluto-results-appear-above-entries/47859)

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**Author:** [@onButtonUp](https://discourse.julialang.org/u/onButtonUp)\
**Replies:** 2\
**Last updated:** [October 7, 2020, 3:51am UTC](https://discourse.julialang.org/t/re-pluto-results-appear-above-entries/47859 "2020-10-07T03:51:45Z")

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Reading top to bottom in a Jupyter notebook seems more natural. Is there an explanation of why the results appear above the entered expressions in Pluto?

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## [Estimating the parameters of ODEs with multiple initial conditions using Bayesian methods](https://discourse.julialang.org/t/estimating-the-parameters-of-odes-with-multiple-initial-conditions-using-bayesian-methods/47903)

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**Author:** [@nyubachi](https://discourse.julialang.org/u/nyubachi)\
**Replies:** 2\
**Last updated:** [October 7, 2020, 2:45am UTC](https://discourse.julialang.org/t/estimating-the-parameters-of-odes-with-multiple-initial-conditions-using-bayesian-methods/47903 "2020-10-07T02:45:15Z")

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Hello. https://tutorials.sciml.ai/html/ode\_extras/04-monte\_carlo\_parameter\_estim.html In the above tutorial, MonteCarloProblem() is used to estimate the parameters for ODEs with multiple initial conditions. I would li…

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## [ForwardDiff.jl does not throw an error even when I try to put in a function outputting an array to calculate the Hessian](https://discourse.julialang.org/t/forwarddiff-jl-does-not-throw-an-error-even-when-i-try-to-put-in-a-function-outputting-an-array-to-calculate-the-hessian/47899)

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**Author:** [@Sarthak\_Choudhury](https://discourse.julialang.org/u/Sarthak_Choudhury)\
**Replies:** 1\
**Last updated:** [October 7, 2020, 12:00am UTC](https://discourse.julialang.org/t/forwarddiff-jl-does-not-throw-an-error-even-when-i-try-to-put-in-a-function-outputting-an-array-to-calculate-the-hessian/47899 "2020-10-07T00:00:36Z")

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Hi everyone, I am new to the forum and a complete beginner in Julia here. I am not sure if this is the correct category to post this doubt. This might already be a redundant doubt if someone else has asked this but I w…

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## [Engineering and ops positions at Beacon Biosignals](https://discourse.julialang.org/t/engineering-and-ops-positions-at-beacon-biosignals/47898)

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**Author:** [@ararslan](https://discourse.julialang.org/u/ararslan)\
**Replies:** 0\
**Last updated:** [October 6, 2020, 10:48pm UTC](https://discourse.julialang.org/t/engineering-and-ops-positions-at-beacon-biosignals/47898 "2020-10-06T22:48:17Z")

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Beacon Biosignals is looking for some talented folks to join our team of dedicated people trying to make EEG analysis ubiquitous in healthcare. We’re using Julia as an integral part of our platform. We have a number of o…

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## [Struct with Custom Constructor throwing error during Testing?](https://discourse.julialang.org/t/struct-with-custom-constructor-throwing-error-during-testing/47896)

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**Author:** [@DataPsycho](https://discourse.julialang.org/u/DataPsycho)\
**Replies:** 4\
**Last updated:** [October 6, 2020, 10:07pm UTC](https://discourse.julialang.org/t/struct-with-custom-constructor-throwing-error-during-testing/47896 "2020-10-06T22:07:24Z")

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Hi, I have defined a constructor as follows: struct ResourceParams screen\_name::String user\_id::Union{Integer, Nothing} since\_id::Union{Integer, Nothing} count::Union{Integer, Nothing} max\_id::Union…

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## [Variables declaration in JuliaPro 1.5.2-1](https://discourse.julialang.org/t/variables-declaration-in-juliapro-1-5-2-1/47802)

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**Author:** [@RaquelSantos](https://discourse.julialang.org/u/RaquelSantos)\
**Replies:** 10\
**Last updated:** [October 6, 2020, 7:58pm UTC](https://discourse.julialang.org/t/variables-declaration-in-juliapro-1-5-2-1/47802 "2020-10-06T19:58:44Z")

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When compiling @variabel on my model, julia displays the following message Expected ModeloDeterministico to be a JuMP model, but it has type DataType error(::String, ::Type{T} where T) at error.jl:42 validmodel(::Type{T…

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## [Plots: retrieve axes width in final figure, and other object dimensions?](https://discourse.julialang.org/t/plots-retrieve-axes-width-in-final-figure-and-other-object-dimensions/47884)

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**Author:** [@lmiq](https://discourse.julialang.org/u/lmiq)\
**Replies:** 0\
**Last updated:** [October 6, 2020, 7:55pm UTC](https://discourse.julialang.org/t/plots-retrieve-axes-width-in-final-figure-and-other-object-dimensions/47884 "2020-10-06T19:55:40Z")

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It would be useful to be able to retrieve the exact dimensions (in pixels, or other consistent units) of the elements of a plot. For instance, if one does: plt = scatter(rand(10),size=(500,500)) display(plt) # or savefi…

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## [How to insert "\\\\" before multiple "\_" in a string?](https://discourse.julialang.org/t/how-to-insert-before-multiple-in-a-string/47882)

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**Author:** [@Ahmed\_Salih](https://discourse.julialang.org/u/Ahmed_Salih)\
**Replies:** 1\
**Last updated:** [October 6, 2020, 7:47pm UTC](https://discourse.julialang.org/t/how-to-insert-before-multiple-in-a-string/47882 "2020-10-06T19:47:35Z")

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Hello! Suppose I have: str = "Hello\_this\_is\_string" How would I make it like this: str\_transform = "Hello\\\\\_this\\\\\_is\\\\\_string" In a programmatic way? Kind regards

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## [Any way to add outer while loops programmatically?](https://discourse.julialang.org/t/any-way-to-add-outer-while-loops-programmatically/47664)

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**Author:** [@Nathan\_Boyer](https://discourse.julialang.org/u/Nathan_Boyer)\
**Replies:** 5\
**Last updated:** [October 6, 2020, 7:43pm UTC](https://discourse.julialang.org/t/any-way-to-add-outer-while-loops-programmatically/47664 "2020-10-06T19:43:41Z")

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I have never come across this need before. I think maybe with meta-programming it is possible, but I have never done that before. I have a function which takes an integer input nknots. For every increase in nknots by on…

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