# Latest

**URL:** https://discourse.julialang.org/latest.md?page=1757

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

**Page:** 1758

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## [Interpolations.jl needs a new maintainer](https://discourse.julialang.org/t/interpolations-jl-needs-a-new-maintainer/37454)

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**Author:** [@tim.holy](https://discourse.julialang.org/u/tim.holy)\
**Replies:** 2\
**Last updated:** [May 4, 2020, 5:31pm UTC](https://discourse.julialang.org/t/interpolations-jl-needs-a-new-maintainer/37454 "2020-05-04T17:31:18Z")

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Interpolations is a native-Julia package for performing interpolations. Tomas Aschan and I wrote most of the package in the well-before-Julia-1.0 days, and since then I’ve been the primary maintainer. The package has rec…

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## [Regression in Flux.jl](https://discourse.julialang.org/t/regression-in-flux-jl/38733)

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**Author:** [@amrods](https://discourse.julialang.org/u/amrods)\
**Replies:** 5\
**Last updated:** [May 4, 2020, 5:09pm UTC](https://discourse.julialang.org/t/regression-in-flux-jl/38733 "2020-05-04T17:09:44Z")

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Trying to get started with Flux.jl. I’m trying estimate a linear regression. I have the following: using Flux using Random Random.seed!(1234) β = \[10., 20., 30.\] # true parameters predict(x) = (x\*β) function loss(x,…

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## [How to temporarily suppress all error and warning messages?](https://discourse.julialang.org/t/how-to-temporarily-suppress-all-error-and-warning-messages/38725)

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**Author:** [@orialb](https://discourse.julialang.org/u/orialb)\
**Replies:** 5\
**Last updated:** [May 4, 2020, 4:01pm UTC](https://discourse.julialang.org/t/how-to-temporarily-suppress-all-error-and-warning-messages/38725 "2020-05-04T16:01:12Z")

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Hi, I want to be able to temporarily suppress all errors and warnings. I tried doing something like this using redirect\_stderr : foo() = @warn "oh oh" io = open("tmp.err","w") redirect\_stderr(io) do foo() end clo…

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## [Install Lsqfit package](https://discourse.julialang.org/t/install-lsqfit-package/38746)

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**Author:** [@mb218](https://discourse.julialang.org/u/mb218)\
**Replies:** 1\
**Last updated:** [May 4, 2020, 3:38pm UTC](https://discourse.julialang.org/t/install-lsqfit-package/38746 "2020-05-04T15:38:33Z")

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I have installed Julia on Windows 10 as JuliaPro (https://juliacomputing.com/products/juliapro.html) LTS (v 1.05-2). I want to run some curve-fitting and LsqFit seems to be the appropriate package. This isn’t included in…

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## [DataFrames, aggregate with missings](https://discourse.julialang.org/t/dataframes-aggregate-with-missings/38737)

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**Author:** [@donquicote](https://discourse.julialang.org/u/donquicote)\
**Replies:** 2\
**Last updated:** [May 4, 2020, 3:25pm UTC](https://discourse.julialang.org/t/dataframes-aggregate-with-missings/38737 "2020-05-04T15:25:45Z")

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Hi! I’m facing the following problem: using DataFrames, Statistics df = DataFrame(A = \[1, 2, missing, missing, missing, 3, 4, 5\], B = \[1, 1, 2, 2, 3, 3, 4, 4\]) df\_mean = aggregate(df, :B, x -\> mean(sk…

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## [A problem with parsing JSON files located at a specific address](https://discourse.julialang.org/t/a-problem-with-parsing-json-files-located-at-a-specific-address/38734)

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**Author:** [@Nash](https://discourse.julialang.org/u/Nash)\
**Replies:** 2\
**Last updated:** [May 4, 2020, 3:21pm UTC](https://discourse.julialang.org/t/a-problem-with-parsing-json-files-located-at-a-specific-address/38734 "2020-05-04T15:21:32Z")

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I am having a great deal of (beginner’s) problems parsing JSON files. Here is the situation: I have a bundle of JSON-files in a specific directory (actually, the content of each file is in JSON-format, but the files do…

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## [Richardson.jl: Richardson extrapolation in Julia](https://discourse.julialang.org/t/richardson-jl-richardson-extrapolation-in-julia/38440)

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**Author:** [@stevengj](https://discourse.julialang.org/u/stevengj)\
**Replies:** 7\
**Last updated:** [April 30, 2020, 1:48am UTC](https://discourse.julialang.org/t/richardson-jl-richardson-extrapolation-in-julia/38440 "2020-04-30T01:48:20Z")

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Richardson extrapolation is a technique for extrapolating a given function f(x) to f(x\_0), taking a one-sided x \\to x\_0 limit without evaluating f(x\_0) explicitly, to high-order accuracy using adaptive polynomial extrapo…

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## [Research engineer / PhD student position in Brussels](https://discourse.julialang.org/t/research-engineer-phd-student-position-in-brussels/38741)

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**Author:** [@barche](https://discourse.julialang.org/u/barche)\
**Replies:** 0\
**Last updated:** [May 4, 2020, 2:57pm UTC](https://discourse.julialang.org/t/research-engineer-phd-student-position-in-brussels/38741 "2020-05-04T14:57:27Z")

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Hi all, I’m very happy to announce that we have a job opening for a PhD student on a new research project (starting in September 2020). The topic of the work is numerical simulation of contaminant dispersion and consequ…

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## [InexactError when plotting Time object](https://discourse.julialang.org/t/inexacterror-when-plotting-time-object/38720)

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**Author:** [@achugb](https://discourse.julialang.org/u/achugb)\
**Replies:** 3\
**Last updated:** [May 4, 2020, 2:07pm UTC](https://discourse.julialang.org/t/inexacterror-when-plotting-time-object/38720 "2020-05-04T14:07:08Z")

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I’m getting an InexactError when I run this code and I can’t figure out why using Plots using Dates y = \[Int(1)\] x=\[Time(now())\] p=plot(x,y) Error showing value of type Plots.Plot{Plots.GRBackend}: ERROR: InexactError…

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## [Questions re Using Julia](https://discourse.julialang.org/t/questions-re-using-julia/38663)

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**Author:** [@pberrett](https://discourse.julialang.org/u/pberrett)\
**Replies:** 28\
**Last updated:** [May 4, 2020, 1:36pm UTC](https://discourse.julialang.org/t/questions-re-using-julia/38663 "2020-05-04T13:36:04Z")

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Hi everyone Please be gentle, this is my first post. I have posted it here because it spans a number of areas. First, I have written a program in python that loads a series of images, analyses them and identifies poten…

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## [Creating a new value using \`jl\_new\_struct\_uninit\`](https://discourse.julialang.org/t/creating-a-new-value-using-jl-new-struct-uninit/37825)

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**Author:** [@barche](https://discourse.julialang.org/u/barche)\
**Replies:** 14\
**Last updated:** [May 4, 2020, 1:16pm UTC](https://discourse.julialang.org/t/creating-a-new-value-using-jl-new-struct-uninit/37825 "2020-05-04T13:16:26Z")

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In CxxWrap, C++ objects are wrapped in a struct like this: struct CxxPtr{T} \<: CxxBaseRef{T} cpp\_object::Ptr{T} end Completely new objects are stored in a mutable version of the above struct, with exactly the same la…

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## [Scatter plots with annotations of points](https://discourse.julialang.org/t/scatter-plots-with-annotations-of-points/37887)

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**Author:** [@Tomas\_Pevny](https://discourse.julialang.org/u/Tomas_Pevny)\
**Replies:** 3\
**Last updated:** [May 4, 2020, 1:07pm UTC](https://discourse.julialang.org/t/scatter-plots-with-annotations-of-points/37887 "2020-05-04T13:07:32Z")

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Dear All, I would like to visualize the output of UMAP in form of a scatterplot, such that when I hover on points, it would show some additional information in textual form (or rendered HTML would be super nice). Thank…

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## [Need help on improving performance of a small subfunction](https://discourse.julialang.org/t/need-help-on-improving-performance-of-a-small-subfunction/38675)

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**Author:** [@O\_Julia](https://discourse.julialang.org/u/O_Julia)\
**Replies:** 21\
**Last updated:** [May 4, 2020, 11:58am UTC](https://discourse.julialang.org/t/need-help-on-improving-performance-of-a-small-subfunction/38675 "2020-05-04T11:58:07Z")

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There is a function in my main program and I have realised that this function consumes most of time in my program. Is it possible to speed up this mentioned function given below function fun1(r::Matrix,od::Int64,γ::Floa…

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## [Core.Box in debugger -- this means?](https://discourse.julialang.org/t/core-box-in-debugger-this-means/38719)

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**Author:** [@blackeneth](https://discourse.julialang.org/u/blackeneth)\
**Replies:** 2\
**Last updated:** [May 4, 2020, 11:15am UTC](https://discourse.julialang.org/t/core-box-in-debugger-this-means/38719 "2020-05-04T11:15:46Z")

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When I start one of my functions in the debugger, I see in the Workspace that my “ct” variable shows up like this – before it is even referenced: After the variable “ct” is assigned, it shows up like this in the works…

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## [Anaconda IJulia installing issue (MbedTLS)](https://discourse.julialang.org/t/anaconda-ijulia-installing-issue-mbedtls/28994)

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**Author:** [@Dito](https://discourse.julialang.org/u/Dito)\
**Replies:** 5\
**Last updated:** [May 4, 2020, 11:48am UTC](https://discourse.julialang.org/t/anaconda-ijulia-installing-issue-mbedtls/28994 "2020-05-04T11:48:34Z")

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I can’t install IJulia on my notebook (High Sierra Version 10.13.6; Julia version 1.2) - Error building ‘MbedTLS’ julia\> using Pkg julia\> Pkg.build("IJulia") Building Conda ──→ \`~/.julia/packages/Conda/kLXeC/deps/bui…

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## [Gadfly - error if shape count more than 15](https://discourse.julialang.org/t/gadfly-error-if-shape-count-more-than-15/38727)

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**Author:** [@Humphrey\_Lee](https://discourse.julialang.org/u/Humphrey_Lee)\
**Replies:** 1\
**Last updated:** [May 4, 2020, 11:47am UTC](https://discourse.julialang.org/t/gadfly-error-if-shape-count-more-than-15/38727 "2020-05-04T11:47:52Z")

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Gadfly shows error if plot has more than 15 shapes (limit!). See code below. using Gadfly x = \[0.025, 0.028, 0.035, 0.036, 0.037, 0.039, 0.039, 0.041, 0.041, 0.041, 0.042, 0.043, 0.045, 0.047, 0.049, 0.051, 0.053, 0.05…

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## [Method of \`open\` that applies a function to various files](https://discourse.julialang.org/t/method-of-open-that-applies-a-function-to-various-files/38732)

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**Author:** [@heliosdrm](https://discourse.julialang.org/u/heliosdrm)\
**Replies:** 5\
**Last updated:** [May 4, 2020, 11:30am UTC](https://discourse.julialang.org/t/method-of-open-that-applies-a-function-to-various-files/38732 "2020-05-04T11:30:28Z")

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I have made this very tiny package to help myself in a very common use case, when I want to read data from big files and write results of processing its contents into another, chunk by chunk. It only contains a new me…

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## [Change SVD.S::Vector{Tr} to SVD.S::AbstractVector{Tr}](https://discourse.julialang.org/t/change-svd-s-vector-tr-to-svd-s-abstractvector-tr/38693)

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**Author:** [@rrhiemstra](https://discourse.julialang.org/u/rrhiemstra)\
**Replies:** 3\
**Last updated:** [May 4, 2020, 10:56am UTC](https://discourse.julialang.org/t/change-svd-s-vector-tr-to-svd-s-abstractvector-tr/38693 "2020-05-04T10:56:39Z")

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I am developing a new package for Kronecker product matrices A ⊗ B ⊗ .... I want to support efficient factorizations for these type of matrices and want to use the types in LinearAlgebra.jl Here follows the type defi…

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## [Opening and reading text: why does Julia insert many "\\"](https://discourse.julialang.org/t/opening-and-reading-text-why-does-julia-insert-many/38731)

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**Author:** [@Nash](https://discourse.julialang.org/u/Nash)\
**Replies:** 3\
**Last updated:** [May 4, 2020, 10:55am UTC](https://discourse.julialang.org/t/opening-and-reading-text-why-does-julia-insert-many/38731 "2020-05-04T10:55:51Z")

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I have a .txt file (the image below shows a snippet): Unfortunately, when I open the file, and read it, Julia inserts many " \\ " and I have no idea why Why does Julia insert " \\ " and how can that be avoided?

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## [InitError: The MATLAB library path could not be found](https://discourse.julialang.org/t/initerror-the-matlab-library-path-could-not-be-found/38729)

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**Author:** [@Ashwin\_Sundarka](https://discourse.julialang.org/u/Ashwin_Sundarka)\
**Replies:** 0\
**Last updated:** [May 4, 2020, 9:15am UTC](https://discourse.julialang.org/t/initerror-the-matlab-library-path-could-not-be-found/38729 "2020-05-04T09:15:10Z")

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julia\> using MATLAB ERROR: InitError: The MATLAB library path could not be found. Stacktrace: \[1\] error(::String) at .\\error.jl:33 \[2\] matlab\_libpath at C:\\Users\\K584961.julia\\packages\\MATLAB\\cVrxc\\src\\mxbase.jl:47 \[…

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## [Proper parametric subtyping of AbstractArray](https://discourse.julialang.org/t/proper-parametric-subtyping-of-abstractarray/38723)

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**Author:** [@tlienart](https://discourse.julialang.org/u/tlienart)\
**Replies:** 4\
**Last updated:** [May 4, 2020, 10:03am UTC](https://discourse.julialang.org/t/proper-parametric-subtyping-of-abstractarray/38723 "2020-05-04T10:03:02Z")

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I ended up banging my head against this yesterday, I guess I’m interested by both the how to do this properly as well as the why did the other ways not work in order to get better at this parametric type business. Aim: …

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## [Way to add tests that utilize jupyter notebooks?](https://discourse.julialang.org/t/way-to-add-tests-that-utilize-jupyter-notebooks/38341)

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**Author:** [@djsegal](https://discourse.julialang.org/u/djsegal)\
**Replies:** 6\
**Last updated:** [May 4, 2020, 9:01am UTC](https://discourse.julialang.org/t/way-to-add-tests-that-utilize-jupyter-notebooks/38341 "2020-05-04T09:01:22Z")

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Was wondering what’s the best way to: run jupyter notebooks during a test suite check the output similar to repl output Would be helpful to have a rosetta stone style answer with tests that are doing string asserts on…

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## [Literate.jl announcement](https://discourse.julialang.org/t/literate-jl-announcement/10651)

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**Author:** [@fredrikekre](https://discourse.julialang.org/u/fredrikekre)\
**Replies:** 47\
**Last updated:** [May 4, 2020, 8:59am UTC](https://discourse.julialang.org/t/literate-jl-announcement/10651 "2020-05-04T08:59:28Z")

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Hello there, I am happy to present Literate.jl, a lightweight package for literate programming. The main purpose is to facilitate writing Julia examples/tutorials that can be included in your package documentation. I b…

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## [Linear Algebra tricks?](https://discourse.julialang.org/t/linear-algebra-tricks/38618)

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**Author:** [@BLI](https://discourse.julialang.org/u/BLI)\
**Replies:** 28\
**Last updated:** [May 4, 2020, 5:59am UTC](https://discourse.julialang.org/t/linear-algebra-tricks/38618 "2020-05-04T05:59:16Z")

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Two questions related to Linear Algebra: I need an identity matrix in some computations. Two ways to achieve this: julia\> Matrix{Integer}(I,3,3) 3×3 Array{Integer,2}: true 0 0 0 true 0 0 0 t…

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## [How do I extract the coefficients and RHS's of all constraints in a JuMP linear program? (Need for KKT)](https://discourse.julialang.org/t/how-do-i-extract-the-coefficients-and-rhss-of-all-constraints-in-a-jump-linear-program-need-for-kkt/38525)

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**Author:** [@nlaws](https://discourse.julialang.org/u/nlaws)\
**Replies:** 14\
**Last updated:** [May 4, 2020, 3:28am UTC](https://discourse.julialang.org/t/how-do-i-extract-the-coefficients-and-rhss-of-all-constraints-in-a-jump-linear-program-need-for-kkt/38525 "2020-05-04T03:28:04Z")

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I am building a bilevel problem and I need to construct the KKT conditions of a linear program written in JuMP. I am wondering if it is possible to extract all the coefficients and right-hand-sides (RHS) of the constrai…

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## [How to map JuMP VariableRef to NLPModelMeta indices?](https://discourse.julialang.org/t/how-to-map-jump-variableref-to-nlpmodelmeta-indices/38681)

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**Author:** [@nlaws](https://discourse.julialang.org/u/nlaws)\
**Replies:** 2\
**Last updated:** [May 4, 2020, 2:52am UTC](https://discourse.julialang.org/t/how-to-map-jump-variableref-to-nlpmodelmeta-indices/38681 "2020-05-04T02:52:07Z")

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I am developing a large scale bilevel problem (1M+ variables), and as a first step I am extracting the constraint coefficient matrix of the lower level linear program using NLPModelMeta (see this post). Here is a simple …

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## [JuliaDB documentation down?](https://discourse.julialang.org/t/juliadb-documentation-down/38703)

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**Author:** [@clibassi](https://discourse.julialang.org/u/clibassi)\
**Replies:** 2\
**Last updated:** [May 4, 2020, 2:43am UTC](https://discourse.julialang.org/t/juliadb-documentation-down/38703 "2020-05-04T02:43:25Z")

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Hi all, Been trying to do some work with memory that is too large for my computer’s memory and so have turned to testing out what I understand to be JuliaDB’s strength in this context, but as I went to read up on it I k…

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## [Point to directory with .txt files, then loop through those files performing actions](https://discourse.julialang.org/t/point-to-directory-with-txt-files-then-loop-through-those-files-performing-actions/38696)

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**Author:** [@Nash](https://discourse.julialang.org/u/Nash)\
**Replies:** 5\
**Last updated:** [May 4, 2020, 1:18am UTC](https://discourse.julialang.org/t/point-to-directory-with-txt-files-then-loop-through-those-files-performing-actions/38696 "2020-05-04T01:18:11Z")

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I have a bundle of .txt files to process. The files are placed at a specific directory. I have written the code for processing any given file, but I need to automate the selection of each file one by one, until all the f…

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## [Converting NamedTuple to DataFrame seems expensive?](https://discourse.julialang.org/t/converting-namedtuple-to-dataframe-seems-expensive/38674)

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**Author:** [@xiaodai](https://discourse.julialang.org/u/xiaodai)\
**Replies:** 7\
**Last updated:** [May 3, 2020, 11:44pm UTC](https://discourse.julialang.org/t/converting-namedtuple-to-dataframe-seems-expensive/38674 "2020-05-03T23:44:49Z")

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I have a huge NamedTuple and DataFrame(larged\_namedtuple) takes a long time like 12s and uses quite a bit of RAM The eventual target for me is a DataFrame but I created the named tuple so that users can choose the …

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## [Boolean matrix factorization in julia?](https://discourse.julialang.org/t/boolean-matrix-factorization-in-julia/38668)

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**Author:** [@Ken-B](https://discourse.julialang.org/u/Ken-B)\
**Replies:** 2\
**Last updated:** [May 3, 2020, 9:29pm UTC](https://discourse.julialang.org/t/boolean-matrix-factorization-in-julia/38668 "2020-05-03T21:29:10Z")

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Anyone know of a package that can do Boolean Matrix Factorization (BMF) in julia? Basically for a boolean matrix A {m x n} and a rank k, find boolean matrix X {m x k} and boolean matrix Y {k x n} such that A = X \* Y (ap…

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