# Specific Domains

**URL:** https://discourse.julialang.org/c/domain/10.md?no_subcategories=false&page=477

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**Page:** 478

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## [Encrypted streams](https://discourse.julialang.org/t/encrypted-streams/30187)

<div class="topic-metadata">

**Author:** [@Janis\_Erdmanis](https://discourse.julialang.org/u/Janis_Erdmanis)\
**Replies:** 3\
**Last updated:** [October 24, 2019, 8:54pm UTC](https://discourse.julialang.org/t/encrypted-streams/30187 "2019-10-24T20:54:54Z")

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Does Julia already have a library which can encrypt streams with a symmetric key? What I need is something simple as: using Sockets server = listen() socket = accept(server) # Some arbitrary key exchange protocol. For …

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## [Julia-Gumbo-webscraping](https://discourse.julialang.org/t/julia-gumbo-webscraping/30203)

<div class="topic-metadata">

**Author:** [@Anil\_Mathews](https://discourse.julialang.org/u/Anil_Mathews)\
**Replies:** 16\
**Last updated:** [October 24, 2019, 1:54pm UTC](https://discourse.julialang.org/t/julia-gumbo-webscraping/30203 "2019-10-24T13:54:16Z")

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Is it possible to convert structure type to julia string type. i have scraped some data from website with Gumbo.jl and i want to push this data to a Array but when i do that i get this error:Cannot convert an object of …

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## [Mosek and Convex.jl -- Still not working](https://discourse.julialang.org/t/mosek-and-convex-jl-still-not-working/30254)

<div class="topic-metadata">

**Author:** [@raktim](https://discourse.julialang.org/u/raktim)\
**Replies:** 3\
**Last updated:** [October 24, 2019, 1:33pm UTC](https://discourse.julialang.org/t/mosek-and-convex-jl-still-not-working/30254 "2019-10-24T13:33:12Z")

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I have been trying to use Convex with Mosek, but it seems there are still some errors. I have been trying to solve the following examples problem: using Convex, Mosek m = 4; n = 5 A = randn(m, n); b = randn(m, 1) x…

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## [Did anyone thought of implementing Octave on top of Julia?](https://discourse.julialang.org/t/did-anyone-thought-of-implementing-octave-on-top-of-julia/30211)

<div class="topic-metadata">

**Author:** [@XVilka](https://discourse.julialang.org/u/XVilka)\
**Replies:** 3\
**Last updated:** [October 23, 2019, 11:35am UTC](https://discourse.julialang.org/t/did-anyone-thought-of-implementing-octave-on-top-of-julia/30211 "2019-10-23T11:35:40Z")

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Apparently, a lot of the Octave/MATLAB features are already available in Julia, and implementing Octave language interpreter would allow to save a lot of time for both worlds. So basically, it will boil down to implement…

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## [How to exclude the columns of a matrix which are present as columns in another matrix](https://discourse.julialang.org/t/how-to-exclude-the-columns-of-a-matrix-which-are-present-as-columns-in-another-matrix/30206)

<div class="topic-metadata">

**Author:** [@Ujku\_KU](https://discourse.julialang.org/u/Ujku_KU)\
**Replies:** 2\
**Last updated:** [October 23, 2019, 8:30am UTC](https://discourse.julialang.org/t/how-to-exclude-the-columns-of-a-matrix-which-are-present-as-columns-in-another-matrix/30206 "2019-10-23T08:30:05Z")

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Hi guys, is there any existing function/method in Julia which checks if the columns of a matrix are columns of another matrix, and remove them from one of the matrices in case there is a positive outcome? Thank you ver…

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## [JuliaCloud for Azure?](https://discourse.julialang.org/t/juliacloud-for-azure/30182)

<div class="topic-metadata">

**Author:** [@stvpwrs](https://discourse.julialang.org/u/stvpwrs)\
**Replies:** 0\
**Last updated:** [October 22, 2019, 6:46pm UTC](https://discourse.julialang.org/t/juliacloud-for-azure/30182 "2019-10-22T18:46:29Z")

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Hello, I am interested in contributing to a Julia project and was wondering if there are any efforts like JuliaCloud AWS for Azure? Steve

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## [Problem construction advice in JuMP for speed](https://discourse.julialang.org/t/problem-construction-advice-in-jump-for-speed/30148)

<div class="topic-metadata">

**Author:** [@bhalonen](https://discourse.julialang.org/u/bhalonen)\
**Replies:** 4\
**Last updated:** [October 22, 2019, 3:50pm UTC](https://discourse.julialang.org/t/problem-construction-advice-in-jump-for-speed/30148 "2019-10-22T15:50:07Z")

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I know that parallelization of problem construction has been advised against, so I am curious on what advice there is. Problem construction takes a significant amount of time on my problem, and is time significant operat…

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## [Trying to get pyplot backend to Plots, but end up with GKS plots anyway](https://discourse.julialang.org/t/trying-to-get-pyplot-backend-to-plots-but-end-up-with-gks-plots-anyway/22038)

<div class="topic-metadata">

**Author:** [@NeonNeon](https://discourse.julialang.org/u/NeonNeon)\
**Replies:** 2\
**Last updated:** [October 22, 2019, 10:53am UTC](https://discourse.julialang.org/t/trying-to-get-pyplot-backend-to-plots-but-end-up-with-gks-plots-anyway/22038 "2019-10-22T10:53:27Z")

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I have several problems using the Plots package together with the PyPlot backend. My exmple looks like this, I have two packages MyPlot and MyFront. In MyPlot’s environment I have added Plots and PyPlot as dependencies…

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## [Simple Flux model not learning](https://discourse.julialang.org/t/simple-flux-model-not-learning/30138)

<div class="topic-metadata">

**Author:** [@rsteckel](https://discourse.julialang.org/u/rsteckel)\
**Replies:** 4\
**Last updated:** [October 21, 2019, 7:05pm UTC](https://discourse.julialang.org/t/simple-flux-model-not-learning/30138 "2019-10-21T19:05:21Z")

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I’ve been trying to get a feel for Flux by modeling a simple non-linear function (X^2). At the end of each epoch, I print the model output for 3 (expecting 9), but it seems to converge to ~34 Can anyone see what I’m do…

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## [Python RL environments from Julia](https://discourse.julialang.org/t/python-rl-environments-from-julia/30123)

<div class="topic-metadata">

**Author:** [@Sarvjeet](https://discourse.julialang.org/u/Sarvjeet)\
**Replies:** 2\
**Last updated:** [October 21, 2019, 6:30pm UTC](https://discourse.julialang.org/t/python-rl-environments-from-julia/30123 "2019-10-21T18:30:59Z")

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Hi there, Since most of the reinforcement learning environments for robotics etc. applications are available in Python so I was wondering if I could implement RL algorithms in Julia and still train those agents written …

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## [Improving Distributions.jl type consistency](https://discourse.julialang.org/t/improving-distributions-jl-type-consistency/30082)

<div class="topic-metadata">

**Author:** [@cscherrer](https://discourse.julialang.org/u/cscherrer)\
**Replies:** 2\
**Last updated:** [October 21, 2019, 1:49pm UTC](https://discourse.julialang.org/t/improving-distributions-jl-type-consistency/30082 "2019-10-21T13:49:13Z")

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The rand(dist, n::Int) method is really handy, but there’s a lot of irregularity in the type that’s returned. Ideally we’d have some type A with typeof(rand(dist, n::Int)) == A{typeof(rand(dist)), n} Having an identity…

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## [Number of nodes and Relative Gap](https://discourse.julialang.org/t/number-of-nodes-and-relative-gap/30133)

<div class="topic-metadata">

**Author:** [@angeloaliano1](https://discourse.julialang.org/u/angeloaliano1)\
**Replies:** 1\
**Last updated:** [October 21, 2019, 1:40pm UTC](https://discourse.julialang.org/t/number-of-nodes-and-relative-gap/30133 "2019-10-21T13:40:26Z")

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Dear users, I am with Julia 1.0.4, JuMP version 0.19 and using the MathOptInterface to solve a integer model. According to the documentation in Reference · MathOptInterface the relative Gap and the number of nodes resea…

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## [Right location/repo for RL algorithms](https://discourse.julialang.org/t/right-location-repo-for-rl-algorithms/30122)

<div class="topic-metadata">

**Author:** [@Sarvjeet](https://discourse.julialang.org/u/Sarvjeet)\
**Replies:** 1\
**Last updated:** [October 21, 2019, 6:05am UTC](https://discourse.julialang.org/t/right-location-repo-for-rl-algorithms/30122 "2019-10-21T06:05:33Z")

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Hi there, I am taking a Deep RL course; would like to implement some deep RL algorithms for practice. I am not sure if I should contribute to Flux.jl, Reinforce.jl, Knet.jl or some other place. Can someone please tell t…

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## [Help me build a Flux.jl model and learn basic ML concepts](https://discourse.julialang.org/t/help-me-build-a-flux-jl-model-and-learn-basic-ml-concepts/30109)

<div class="topic-metadata">

**Author:** [@mthelm85](https://discourse.julialang.org/u/mthelm85)\
**Replies:** 1\
**Last updated:** [October 20, 2019, 2:22pm UTC](https://discourse.julialang.org/t/help-me-build-a-flux-jl-model-and-learn-basic-ml-concepts/30109 "2019-10-20T14:22:25Z")

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I am learning the basics of ML/Flux.jl and I’m trying to build a simple model to get started. I grabbed some data from the U.S. Census Bureau and went ahead and created a gist on GitHub that contains a small cut (3,000 r…

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## [Support for HTML data (not HTML strings)](https://discourse.julialang.org/t/support-for-html-data-not-html-strings/14142)

<div class="topic-metadata">

**Author:** [@essenciary](https://discourse.julialang.org/u/essenciary)\
**Replies:** 11\
**Last updated:** [October 19, 2019, 10:34pm UTC](https://discourse.julialang.org/t/support-for-html-data-not-html-strings/14142 "2019-10-19T22:34:59Z")

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Wondering if there’s any way of adding support for HTML data in Julia. Something like: dom = \<section\>\<h1\>Foo\</h1\>\<p\>Hello\</p\>\</section\> instead of dom = "\<section\>\<h1\>Foo\</h1\>\<p\>Hello\</p\>\</section\>" (extra quotes he…

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## [How to undershand the Objective goes greater while itering?](https://discourse.julialang.org/t/how-to-undershand-the-objective-goes-greater-while-itering/29721)

<div class="topic-metadata">

**Author:** [@kuro26](https://discourse.julialang.org/u/kuro26)\
**Replies:** 5\
**Last updated:** [October 19, 2019, 2:46pm UTC](https://discourse.julialang.org/t/how-to-undershand-the-objective-goes-greater-while-itering/29721 "2019-10-19T14:46:05Z")

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This is the iteration process for a problem, the result in iter 19 still acceptable. In my understanding of optimization, this should not happen! Is anybody know why waa that? I am really puzzled

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## [Pandas's fast isin() equivalent in Julia DataFrame or IndexedTable or anything else](https://discourse.julialang.org/t/pandass-fast-isin-equivalent-in-julia-dataframe-or-indexedtable-or-anything-else/30073)

<div class="topic-metadata">

**Author:** [@Sijun](https://discourse.julialang.org/u/Sijun)\
**Replies:** 5\
**Last updated:** [October 19, 2019, 11:05am UTC](https://discourse.julialang.org/t/pandass-fast-isin-equivalent-in-julia-dataframe-or-indexedtable-or-anything-else/30073 "2019-10-19T11:05:13Z")

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Python Pandas DataFrame’s isin() is really fast. for example: import numpy as np import pandas as pd df = pd.DataFrame({"x": np.random.randint(1,100, size=(10\*\*6,)), "y": np.random.randint(50,149, size=…

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## [Turing.jl - NUTS/sample parameters](https://discourse.julialang.org/t/turing-jl-nuts-sample-parameters/30058)

<div class="topic-metadata">

**Author:** [@mthelm85](https://discourse.julialang.org/u/mthelm85)\
**Replies:** 2\
**Last updated:** [October 19, 2019, 1:54am UTC](https://discourse.julialang.org/t/turing-jl-nuts-sample-parameters/30058 "2019-10-19T01:54:25Z")

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Hello, I’m trying to learn Turing.jl and the concepts behind it and I’m not seeing any documentation that explains what the parameters are that are passed to NUTS() when sampling. The documentation utilizes the NUTS sam…

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## [Dataset access - Python](https://discourse.julialang.org/t/dataset-access-python/30048)

<div class="topic-metadata">

**Author:** [@johnh](https://discourse.julialang.org/u/johnh)\
**Replies:** 7\
**Last updated:** [October 18, 2019, 9:46pm UTC](https://discourse.julialang.org/t/dataset-access-python/30048 "2019-10-18T21:46:50Z")

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@oxinabox will set me right here. I recall looking at https://github.com/oxinabox/DataDepsGenerators.jl There is a Python standard for accessing datasets which was mentioned at the time. Or am I imagining this? I ask s…

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## [Copyto! does not work for subarray when scalar get index is disallowed?](https://discourse.julialang.org/t/copyto-does-not-work-for-subarray-when-scalar-get-index-is-disallowed/30044)

<div class="topic-metadata">

**Author:** [@ww1g11](https://discourse.julialang.org/u/ww1g11)\
**Replies:** 1\
**Last updated:** [October 18, 2019, 9:34am UTC](https://discourse.julialang.org/t/copyto-does-not-work-for-subarray-when-scalar-get-index-is-disallowed/30044 "2019-10-18T09:34:07Z")

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I have a large Array in CPU and want to copy back the GPU data to it. Here is a demo: using CuArrays CuArrays.allowscalar(false) N = 100 u\_c = rand(N, 2); u\_d = CuArrays.CuArray(ones(N)); u\_v = view(u\_c, :, 1); copyto!(…

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## [Flux.jl MethodError ... (::Dense{typeof(identity),... on simple Chain model](https://discourse.julialang.org/t/flux-jl-methoderror-dense-typeof-identity-on-simple-chain-model/29247)

<div class="topic-metadata">

**Author:** [@m\_Tucci](https://discourse.julialang.org/u/m_Tucci)\
**Replies:** 3\
**Last updated:** [October 17, 2019, 12:38pm UTC](https://discourse.julialang.org/t/flux-jl-methoderror-dense-typeof-identity-on-simple-chain-model/29247 "2019-10-17T12:38:38Z")

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Hi, I’m new to using Flux and I keep getting a data type error when running the following code: using LinearAlgebra, Flux, Base.Iterators, Statistics using CuArrays using Flux: onehotbatch, onecold, crossentropy, thrott…

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## [Custom RNN with Flux gives an error with Flux.train!](https://discourse.julialang.org/t/custom-rnn-with-flux-gives-an-error-with-flux-train/30008)

<div class="topic-metadata">

**Author:** [@KK\_JuliaNoob](https://discourse.julialang.org/u/KK_JuliaNoob)\
**Replies:** 0\
**Last updated:** [October 17, 2019, 3:56am UTC](https://discourse.julialang.org/t/custom-rnn-with-flux-gives-an-error-with-flux-train/30008 "2019-10-17T03:56:09Z")

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I am making a custom RNN layer based on the code in recurrent.jl in the Flux code base. However, when I try to train the model using the task given in the character rnn model zoo example (char-rnn.jl), I get an error sa…

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## [VScode can't find reference in dev folder](https://discourse.julialang.org/t/vscode-cant-find-reference-in-dev-folder/29836)

<div class="topic-metadata">

**Author:** [@affans](https://discourse.julialang.org/u/affans)\
**Replies:** 5\
**Last updated:** [October 16, 2019, 6:52pm UTC](https://discourse.julialang.org/t/vscode-cant-find-reference-in-dev-folder/29836 "2019-10-16T18:52:46Z")

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I have a package in my dev folder that I am developing locally. Typing in using pkgname in Julia REPL works well. However, in VSCode it can’t seem to find the reference (in my context I am writing unit tests for my packa…

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## [Building and solving a cascade of ODEs using DifferentialEquations](https://discourse.julialang.org/t/building-and-solving-a-cascade-of-odes-using-differentialequations/29963)

<div class="topic-metadata">

**Author:** [@zdenek\_hurak](https://discourse.julialang.org/u/zdenek_hurak)\
**Replies:** 5\
**Last updated:** [October 16, 2019, 6:49pm UTC](https://discourse.julialang.org/t/building-and-solving-a-cascade-of-odes-using-differentialequations/29963 "2019-10-16T18:49:49Z")

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I want to build and solve a cascade of ODEs, by which term I mean that the first derivative of the k-th component of the vector x of (state) variables with respect to time t depends on x\_{k}(t) itself and on the precedin…

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## [Soss relating to the broader PPL ecosystem](https://discourse.julialang.org/t/soss-relating-to-the-broader-ppl-ecosystem/29785)

<div class="topic-metadata">

**Author:** [@cscherrer](https://discourse.julialang.org/u/cscherrer)\
**Replies:** 5\
**Last updated:** [October 16, 2019, 3:47pm UTC](https://discourse.julialang.org/t/soss-relating-to-the-broader-ppl-ecosystem/29785 "2019-10-16T15:47:58Z")

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Hello Julia PPL, I’ve been thinking some more about how Soss might relate to other PPL work. Hope I might get your thoughts on this, and how it might benefit the community as a whole. The big idea is that Soss is proba…

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## [How to use multiple GPUs correctly?](https://discourse.julialang.org/t/how-to-use-multiple-gpus-correctly/29986)

<div class="topic-metadata">

**Author:** [@ww1g11](https://discourse.julialang.org/u/ww1g11)\
**Replies:** 2\
**Last updated:** [October 16, 2019, 3:12pm UTC](https://discourse.julialang.org/t/how-to-use-multiple-gpus-correctly/29986 "2019-10-16T15:12:42Z")

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Hi all, I am trying to change my GPU code to use multiple GPUs due to the memory limit of a single GPU. I found an example (Multiple-GPU Parallelism on the HPC with Julia | juliabloggers.com) and the basic idea is sp…

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## [\[DataFrames Question\]: hash-based row indexing for DataFrames package](https://discourse.julialang.org/t/dataframes-question-hash-based-row-indexing-for-dataframes-package/29925)

<div class="topic-metadata">

**Author:** [@Sijun](https://discourse.julialang.org/u/Sijun)\
**Replies:** 16\
**Last updated:** [October 16, 2019, 1:58am UTC](https://discourse.julialang.org/t/dataframes-question-hash-based-row-indexing-for-dataframes-package/29925 "2019-10-16T01:58:04Z")

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Question: Any plan for hash-based indexing for DataFrame Suppose the following table is given (actual table that I work on contains about a million records): df = DataFrame(id=\[7,1,5,3,4,6,2\], val=\[5,6,9,3,4,10,4\]) Now…

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## [Yet another question about solving an ODE with inputs using DifferentialEquations](https://discourse.julialang.org/t/yet-another-question-about-solving-an-ode-with-inputs-using-differentialequations/29960)

<div class="topic-metadata">

**Author:** [@zdenek\_hurak](https://discourse.julialang.org/u/zdenek_hurak)\
**Replies:** 1\
**Last updated:** [October 15, 2019, 11:43pm UTC](https://discourse.julialang.org/t/yet-another-question-about-solving-an-ode-with-inputs-using-differentialequations/29960 "2019-10-15T23:43:01Z")

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This is yet another question related to the obviously popular basic problem of solving an ODE (or a system of ODEs) with inputs in Julia (using DifferentialEquations package). Let’s consider a single (scalar) ODE of the…

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## [DataFrames, best way to import from JSON format file](https://discourse.julialang.org/t/dataframes-best-way-to-import-from-json-format-file/29946)

<div class="topic-metadata">

**Author:** [@4aHxKzD](https://discourse.julialang.org/u/4aHxKzD)\
**Replies:** 6\
**Last updated:** [October 15, 2019, 10:55pm UTC](https://discourse.julialang.org/t/dataframes-best-way-to-import-from-json-format-file/29946 "2019-10-15T22:55:03Z")

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Hi. I’m coming from Python and would like to know what is the current “standard” on how to import from a JSON file to a DataFrame data structure, i.e., the equivalent to pandas.read\_json().

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## [Univariate linear regression with each covariate of dataframe](https://discourse.julialang.org/t/univariate-linear-regression-with-each-covariate-of-dataframe/29951)

<div class="topic-metadata">

**Author:** [@sergevic](https://discourse.julialang.org/u/sergevic)\
**Replies:** 5\
**Last updated:** [October 15, 2019, 7:16pm UTC](https://discourse.julialang.org/t/univariate-linear-regression-with-each-covariate-of-dataframe/29951 "2019-10-15T19:16:47Z")

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I have a dataframe with 5 covariates X1, X2, X3, X4, X5 and a dependent variable Y. I have to perform a univariate regression of Y on each covariate. I don’t want to do using GLM lm(@formula(Y~X1), data) lm(@formula(Y~X…

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