# New to Julia

**URL:** https://discourse.julialang.org/c/first-steps/8.md?page=54

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**Page:** 55

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## [Alternative for flamegraphs](https://discourse.julialang.org/t/alternative-for-flamegraphs/110267)

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**Author:** [@Matthijs\_1971](https://discourse.julialang.org/u/Matthijs_1971)\
**Replies:** 3\
**Last updated:** [February 16, 2024, 5:43pm UTC](https://discourse.julialang.org/t/alternative-for-flamegraphs/110267 "2024-02-16T17:43:36Z")

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Flamegraphs are created by polling the stacktrace and post-processing the results, lumping together parts of stacktraces. If my code calls functions tic() and toc() alternatingly, a flamegraph lumps together all calls to…

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## [Plotting a sequence of images as a gif](https://discourse.julialang.org/t/plotting-a-sequence-of-images-as-a-gif/23808)

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**Author:** [@mllera14](https://discourse.julialang.org/u/mllera14)\
**Replies:** 33\
**Last updated:** [February 16, 2024, 9:52am UTC](https://discourse.julialang.org/t/plotting-a-sequence-of-images-as-a-gif/23808 "2024-02-16T09:52:10Z")

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Hi, I have an input signal parameterized by time, which consists of a time dependent noise mask added on top of a base image defined as: I(t) = X + noise(t) I now want to create a gif animation using Plots to see what…

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## [How to create a streamplot only inside a polygon?](https://discourse.julialang.org/t/how-to-create-a-streamplot-only-inside-a-polygon/110273)

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**Author:** [@Midez](https://discourse.julialang.org/u/Midez)\
**Replies:** 2\
**Last updated:** [February 15, 2024, 11:20pm UTC](https://discourse.julialang.org/t/how-to-create-a-streamplot-only-inside-a-polygon/110273 "2024-02-15T23:20:13Z")

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Say I got a triangle defined by using CairoMakie, GeometryBasics, DelaunayTriangulation P = \[(-1,0),(1,0),(0,1),(-1,0)\] Now let’s triangulate the triangle to get equal points (x,y) indside boundary\_nodes, points = c…

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## [Matching filtered Vector{String} to non-filtered Matrix{Any} - GPS station names](https://discourse.julialang.org/t/matching-filtered-vector-string-to-non-filtered-matrix-any-gps-station-names/110230)

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**Author:** [@GeodeticR](https://discourse.julialang.org/u/GeodeticR)\
**Replies:** 9\
**Last updated:** [February 15, 2024, 7:44pm UTC](https://discourse.julialang.org/t/matching-filtered-vector-string-to-non-filtered-matrix-any-gps-station-names/110230 "2024-02-15T19:44:51Z")

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Hello all, I’ve been attempting to match an array of GPS stations names that I’ve filtered such that I have a time frame I’m interested and that the percentage of collection in that time is \> 93%. The issue is, that I …

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## [Lux.jl LSTM timeseries prediction: AD / optimization does not start](https://discourse.julialang.org/t/lux-jl-lstm-timeseries-prediction-ad-optimization-does-not-start/107553)

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**Author:** [@OliverWallscheid](https://discourse.julialang.org/u/OliverWallscheid)\
**Replies:** 2\
**Last updated:** [February 14, 2024, 10:50pm UTC](https://discourse.julialang.org/t/lux-jl-lstm-timeseries-prediction-ad-optimization-does-not-start/107553 "2024-02-14T22:50:50Z")

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Hey there, I am trying to compile a training session of a simple time series prediction example using a LSTM cell within a Lux chain. My model is model = Lux.Chain(Lux.Dense(2 =\> 2), Lux.Recurrence(Lux.LSTMCell(2 =\> 2…

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## [Algorithm for product of vectors](https://discourse.julialang.org/t/algorithm-for-product-of-vectors/110049)

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**Author:** [@blociss](https://discourse.julialang.org/u/blociss)\
**Replies:** 32\
**Last updated:** [February 14, 2024, 8:39pm UTC](https://discourse.julialang.org/t/algorithm-for-product-of-vectors/110049 "2024-02-14T20:39:26Z")

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Consider uu=\[ \[ ((1, 2), (3, -2)), ((1, 3), (3, -3))\], \[ ((1, -1), (2, 1))\], \[((1, 1), (2, -1)), ((1, -1), (2, 1))\], \[ ((2, -2), (4, 2)), ((2, -3), (4, 3))\], \[((3, 1), (4, -1)), ((3, 4), (4, -4))\], \[((3, 1), (4, …

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## [Please someone explain me the array indexing example from manual?](https://discourse.julialang.org/t/please-someone-explain-me-the-array-indexing-example-from-manual/110174)

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**Author:** [@benibilme](https://discourse.julialang.org/u/benibilme)\
**Replies:** 5\
**Last updated:** [February 14, 2024, 1:48pm UTC](https://discourse.julialang.org/t/please-someone-explain-me-the-array-indexing-example-from-manual/110174 "2024-02-14T13:48:31Z")

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I am truly lost at following example. I appreciate any directions, I seem to understand all previous examples, but this one just made me dazzle. Julia 1.10 manual array indexing section If I\_1 is changed to a two-dime…

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## [Problem with LSTM and GRU Layers in Flux](https://discourse.julialang.org/t/problem-with-lstm-and-gru-layers-in-flux/110058)

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**Author:** [@LucaGeminiani00](https://discourse.julialang.org/u/LucaGeminiani00)\
**Replies:** 9\
**Last updated:** [February 14, 2024, 8:29am UTC](https://discourse.julialang.org/t/problem-with-lstm-and-gru-layers-in-flux/110058 "2024-02-14T08:29:57Z")

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I have built a Time series forecasting model in Flux.jl including an LSTM layer (the problem is the same also when I include a GRU layer). I am able to train the model without errors. However, when I try to run: model(va…

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## [Running a @distributed for loop on a zipped variable fails?](https://discourse.julialang.org/t/running-a-distributed-for-loop-on-a-zipped-variable-fails/110166)

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**Author:** [@Alexandre\_Champagne](https://discourse.julialang.org/u/Alexandre_Champagne)\
**Replies:** 1\
**Last updated:** [February 13, 2024, 5:58pm UTC](https://discourse.julialang.org/t/running-a-distributed-for-loop-on-a-zipped-variable-fails/110166 "2024-02-13T17:58:31Z")

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Hi, I’m trying to loop over a combination of parameters (N, f, o), and each iteration is also identified using an index (i). The code below works, but fails when using distributed with a bunch of cryptic error messages …

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## [String operation](https://discourse.julialang.org/t/string-operation/110140)

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**Author:** [@madsnesse](https://discourse.julialang.org/u/madsnesse)\
**Replies:** 7\
**Last updated:** [February 13, 2024, 5:32pm UTC](https://discourse.julialang.org/t/string-operation/110140 "2024-02-13T17:32:51Z")

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what does this do in julia? it does not give any ParseError, and when executed in REPL it just displays the name of the variable (a) a = "abc" "aa" a OUTPUT: julia\> "aa" a a If I change the order like this it gives P…

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## [Embedding the REPL](https://discourse.julialang.org/t/embedding-the-repl/110153)

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**Author:** [@joelreymont](https://discourse.julialang.org/u/joelreymont)\
**Replies:** 2\
**Last updated:** [February 13, 2024, 2:27pm UTC](https://discourse.julialang.org/t/embedding-the-repl/110153 "2024-02-13T14:27:19Z")

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How can I embed the Julia REPL into a C++ executable such that I can connect to it remotely, e.g. from a notebook? I know about the C++ interop packages but haven’t found anything on the REPL. Thanks, Joel

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## [Solving a system of equations symbolically](https://discourse.julialang.org/t/solving-a-system-of-equations-symbolically/110141)

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**Author:** [@skvibimigger](https://discourse.julialang.org/u/skvibimigger)\
**Replies:** 3\
**Last updated:** [February 13, 2024, 12:14pm UTC](https://discourse.julialang.org/t/solving-a-system-of-equations-symbolically/110141 "2024-02-13T12:14:17Z")

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I need to solve a system of equations. Everything works until the part where I want to solve for the coefficients which I have stored in the vector a: Is there a way to solve for these coefficients? My script is the f…

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## [Handling callbacks](https://discourse.julialang.org/t/handling-callbacks/110096)

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**Author:** [@Gabriel\_Carita](https://discourse.julialang.org/u/Gabriel_Carita)\
**Replies:** 2\
**Last updated:** [February 13, 2024, 8:38am UTC](https://discourse.julialang.org/t/handling-callbacks/110096 "2024-02-13T08:38:04Z")

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Hi there, I need to verify collisions between two rotating ellipses. At the moment, I’m using continuous callbacks; however, I’m not sure if this is the most efficient way or how to do it. I need the collisions to be ch…

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## [Remove the last char from an IOBuffer in-place?](https://discourse.julialang.org/t/remove-the-last-char-from-an-iobuffer-in-place/109128)

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**Author:** [@putianyi888](https://discourse.julialang.org/u/putianyi888)\
**Replies:** 1\
**Last updated:** [February 13, 2024, 3:21am UTC](https://discourse.julialang.org/t/remove-the-last-char-from-an-iobuffer-in-place/109128 "2024-02-13T03:21:50Z")

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I’m trying to append to a string so I use an IOBuffer as it operates in place. I tried to print \\b but it’s reserved in the IOBuffer: julia\> io=IOBuffer() IOBuffer(data=UInt8\[...\], readable=true, writable=true, seekable…

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## [Vscode problem](https://discourse.julialang.org/t/vscode-problem/110100)

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**Author:** [@jackmarry](https://discourse.julialang.org/u/jackmarry)\
**Replies:** 7\
**Last updated:** [February 12, 2024, 8:05pm UTC](https://discourse.julialang.org/t/vscode-problem/110100 "2024-02-12T20:05:07Z")

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When I use debugger, this message pops up: Terminal will be reused by tasks, press any key to close it.

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## [JuliaFEM failed to precompile](https://discourse.julialang.org/t/juliafem-failed-to-precompile/109908)

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**Author:** [@Mishal](https://discourse.julialang.org/u/Mishal)\
**Replies:** 9\
**Last updated:** [February 12, 2024, 10:58am UTC](https://discourse.julialang.org/t/juliafem-failed-to-precompile/109908 "2024-02-12T10:58:57Z")

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Hi Guys I am new to Julia, I have tried to install the JuliaFEM package however there seems to be some issues, please refer to the below errors when running the test. I have seen a post about this with the solution requ…

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## [Why does recursive dereferencing occur during printing of a tree?](https://discourse.julialang.org/t/why-does-recursive-dereferencing-occur-during-printing-of-a-tree/110008)

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**Author:** [@Julia2001](https://discourse.julialang.org/u/Julia2001)\
**Replies:** 12\
**Last updated:** [February 12, 2024, 3:31am UTC](https://discourse.julialang.org/t/why-does-recursive-dereferencing-occur-during-printing-of-a-tree/110008 "2024-02-12T03:31:35Z")

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Hi! With my bidirectional tree (see below) I fell into the “circular reference” trap which makes me wonder why Julia (or something inside Julia?) shows this behavior in the first place. Coming from C I would expect the…

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## [SIMD.jl/shufflevector without support for SIMD vector as mask?](https://discourse.julialang.org/t/simd-jl-shufflevector-without-support-for-simd-vector-as-mask/110079)

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**Author:** [@Julia2001](https://discourse.julialang.org/u/Julia2001)\
**Replies:** 2\
**Last updated:** [February 11, 2024, 9:19pm UTC](https://discourse.julialang.org/t/simd-jl-shufflevector-without-support-for-simd-vector-as-mask/110079 "2024-02-11T21:19:03Z")

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Hi! Could anybody explain a bit on why SIMD.jl/shufflevector does not accept a Vec{N, T} object as “mask” argument. Wouldn’t it be a natural choice to allow “mask” to be a SIMD vector? Is this an LLVM limitation? Is …

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## [Error: SymbolicUtils.BasicSymbolic{Real}\[a, b, c, d\] are missing from the variable map](https://discourse.julialang.org/t/error-symbolicutils-basicsymbolic-real-a-b-c-d-are-missing-from-the-variable-map/110054)

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**Author:** [@orebas](https://discourse.julialang.org/u/orebas)\
**Replies:** 1\
**Last updated:** [February 11, 2024, 8:37am UTC](https://discourse.julialang.org/t/error-symbolicutils-basicsymbolic-real-a-b-c-d-are-missing-from-the-variable-map/110054 "2024-02-11T08:37:01Z")

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I believe this is the same error as from Missing from the variable map error Specifically, I have created a ModelingToolkit ODESystem, saved it into a variable, and passed that variable to a function. The below is an M…

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## [How to remove edge lines when drawing a triangle mesh with Makie?](https://discourse.julialang.org/t/how-to-remove-edge-lines-when-drawing-a-triangle-mesh-with-makie/110044)

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**Author:** [@Midez](https://discourse.julialang.org/u/Midez)\
**Replies:** 0\
**Last updated:** [February 10, 2024, 8:32pm UTC](https://discourse.julialang.org/t/how-to-remove-edge-lines-when-drawing-a-triangle-mesh-with-makie/110044 "2024-02-10T20:32:36Z")

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Briefly if I run using CairoMakie, Makie, DelaunayTriangulation, GeometryBasics P = \[ (0.0,0.0),(2.0,1.0),(4.0,0.0), (6.0,2.0),(2.0,3.0),(3.0,4.0), (6.0,6.0),(0.0,6.0),(0.0,0.0) \] boundary\_nodes, points = convert\_bo…

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## [Online Documentation: improving navigation](https://discourse.julialang.org/t/online-documentation-improving-navigation/110037)

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**Author:** [@JimCircadian](https://discourse.julialang.org/u/JimCircadian)\
**Replies:** 3\
**Last updated:** [February 10, 2024, 7:19pm UTC](https://discourse.julialang.org/t/online-documentation-improving-navigation/110037 "2024-02-10T19:19:16Z")

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I imagine this might well have been discussed and / or considered, but as I find it a particular barrier to ease-of-learning with Julia (and am totally willing to contribute to change :wink:) I wanted to ask this obvious…

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## [Pattern recognition](https://discourse.julialang.org/t/pattern-recognition/110028)

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**Author:** [@Andrew\_Palfreyman](https://discourse.julialang.org/u/Andrew_Palfreyman)\
**Replies:** 3\
**Last updated:** [February 10, 2024, 3:51pm UTC](https://discourse.julialang.org/t/pattern-recognition/110028 "2024-02-10T15:51:21Z")

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I am a novice Julia user and investigating its capabilities. Is it capable of pattern recognition? Here’s an example: For E(n)=n^2 -n + p, p=41, p \<=n \<2p; There exists a mixture of primes and composites. The composite…

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## [How to convert Vector{Point2{Float64}} to Vector{Tuple{Float64, Float64}}:](https://discourse.julialang.org/t/how-to-convert-vector-point2-float64-to-vector-tuple-float64-float64/110026)

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**Author:** [@Midez](https://discourse.julialang.org/u/Midez)\
**Replies:** 10\
**Last updated:** [February 10, 2024, 1:35pm UTC](https://discourse.julialang.org/t/how-to-convert-vector-point2-float64-to-vector-tuple-float64-float64/110026 "2024-02-10T13:35:18Z")

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Actually the title says it all. How to perform this conversion ? I haven’t found anything.

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## [How to efficiently apply user-defined functions against grouped dataframes in \`DataFrames.jl\`?](https://discourse.julialang.org/t/how-to-efficiently-apply-user-defined-functions-against-grouped-dataframes-in-dataframes-jl/109963)

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**Author:** [@anon56682678](https://discourse.julialang.org/u/anon56682678)\
**Replies:** 6\
**Last updated:** [February 10, 2024, 11:46am UTC](https://discourse.julialang.org/t/how-to-efficiently-apply-user-defined-functions-against-grouped-dataframes-in-dataframes-jl/109963 "2024-02-10T11:46:59Z")

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I am translating about 6k lines of R to Julia for the sake of speed and everything has been faster, significantly faster in Julia except for this specific task. I suspect what I have done below may not be the right way t…

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## [Error when "using Symbolics"](https://discourse.julialang.org/t/error-when-using-symbolics/109899)

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**Author:** [@brombo](https://discourse.julialang.org/u/brombo)\
**Replies:** 12\
**Last updated:** [February 9, 2024, 9:29pm UTC](https://discourse.julialang.org/t/error-when-using-symbolics/109899 "2024-02-09T21:29:24Z")

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I am trying to use the “Symbolics” package but when I have a program that consists only of the line “using Symbolics” I get the error - WARNING: Method definition isapprox(IntervalSets.AbstractInterval{T} where T, Inter…

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## [Problem using functions from ScenTrees Package](https://discourse.julialang.org/t/problem-using-functions-from-scentrees-package/109985)

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**Author:** [@heiwie](https://discourse.julialang.org/u/heiwie)\
**Replies:** 3\
**Last updated:** [February 9, 2024, 3:23pm UTC](https://discourse.julialang.org/t/problem-using-functions-from-scentrees-package/109985 "2024-02-09T15:23:07Z")

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I am trying to run the same code as in the official github repo for the ScenTrees package (GitHub - aloispichler/ScenTrees.jl: Julia Package for Generating Scenario Trees and Scenario Lattices for Multistage Stochastic O…

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## [Calling functions from another script](https://discourse.julialang.org/t/calling-functions-from-another-script/109978)

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**Author:** [@Mishal](https://discourse.julialang.org/u/Mishal)\
**Replies:** 2\
**Last updated:** [February 9, 2024, 2:58pm UTC](https://discourse.julialang.org/t/calling-functions-from-another-script/109978 "2024-02-09T14:58:11Z")

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Hi Guys I am currently converting my FEM toolbox I made on Matlab to Julia. I am having issues calling functions from other scripts. the function is: function assembly(q, T, ke, npe, dof, n) # Create a blank globa…

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## [Select a dictionary in a vector based on a specific entry value](https://discourse.julialang.org/t/select-a-dictionary-in-a-vector-based-on-a-specific-entry-value/109876)

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**Author:** [@sardinecan](https://discourse.julialang.org/u/sardinecan)\
**Replies:** 4\
**Last updated:** [February 9, 2024, 2:48pm UTC](https://discourse.julialang.org/t/select-a-dictionary-in-a-vector-based-on-a-specific-entry-value/109876 "2024-02-09T14:48:54Z")

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Hi everyone, I’m looking for an easy way to filter/select dict in vector based on the value of one of the key. In the example below, I need to find the title of a data, given by the first Dict of the vector (but it is …

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## [Interactively cropping a TIFF stack?](https://discourse.julialang.org/t/interactively-cropping-a-tiff-stack/66020)

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**Author:** [@DTL](https://discourse.julialang.org/u/DTL)\
**Replies:** 7\
**Last updated:** [February 9, 2024, 2:42pm UTC](https://discourse.julialang.org/t/interactively-cropping-a-tiff-stack/66020 "2024-02-09T14:42:46Z")

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I’ve got some 8-bit TIFF stacks, on the order of 300x300x150 (x \* y \* slices) in size. I can load these into Julia fine and display them, what I’d really like to be able to do now is interactively crop out a region defin…

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## [Pre-processing data within a Julia structure](https://discourse.julialang.org/t/pre-processing-data-within-a-julia-structure/109979)

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**Author:** [@RogerV](https://discourse.julialang.org/u/RogerV)\
**Replies:** 2\
**Last updated:** [February 9, 2024, 1:24pm UTC](https://discourse.julialang.org/t/pre-processing-data-within-a-julia-structure/109979 "2024-02-09T13:24:24Z")

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I would like to have a Julia structure with data and parameters contained with it, to be used with various functions. E.g., I start with data frame of numbers, but many functions use it as a matrix and also need to know …

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