# Latest

**URL:** https://discourse.julialang.org/latest.md?page=1673

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

**Page:** 1674

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## [Why Julia can execute code when macros are expanded?](https://discourse.julialang.org/t/why-julia-can-execute-code-when-macros-are-expanded/43987)

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**Author:** [@Hawk](https://discourse.julialang.org/u/Hawk)\
**Replies:** 6\
**Last updated:** [August 1, 2020, 9:04am UTC](https://discourse.julialang.org/t/why-julia-can-execute-code-when-macros-are-expanded/43987 "2020-08-01T09:04:41Z")

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Hi, when I read the section of metaprogramming in Tom Kwong’s Book “Hands-on Design Patterns and Best Practices with Julia”, I came across such an example: macro identity(ex) dump(ex) return ex end And then when…

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## [Opening sequence for talks at JuliaCon](https://discourse.julialang.org/t/opening-sequence-for-talks-at-juliacon/44075)

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**Author:** [@johnh](https://discourse.julialang.org/u/johnh)\
**Replies:** 0\
**Last updated:** [August 1, 2020, 7:24am UTC](https://discourse.julialang.org/t/opening-sequence-for-talks-at-juliacon/44075 "2020-08-01T07:24:06Z")

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The opening graphics and the music sequence for the start of talks at JuliaCon was stunning. Please can we use this for more Julia talks? The music had the right mix of ‘hey something exciting is going to happen’ And o…

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## [Speed improvement possible?](https://discourse.julialang.org/t/speed-improvement-possible/44065)

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**Author:** [@Ruan\_Stander](https://discourse.julialang.org/u/Ruan_Stander)\
**Replies:** 1\
**Last updated:** [August 1, 2020, 6:46am UTC](https://discourse.julialang.org/t/speed-improvement-possible/44065 "2020-08-01T06:46:14Z")

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Would appreciate tips to improve speed of code below. Transforms a dataset into an input matrix and corresponding output whilst skipping missing output values function AddMatrixToInput!(row,day,instrument,Imatrix,pcMatr…

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## [Initialize a variable inside a struct](https://discourse.julialang.org/t/initialize-a-variable-inside-a-struct/43967)

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**Author:** [@Johncowk](https://discourse.julialang.org/u/Johncowk)\
**Replies:** 14\
**Last updated:** [August 1, 2020, 1:46am UTC](https://discourse.julialang.org/t/initialize-a-variable-inside-a-struct/43967 "2020-08-01T01:46:40Z")

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I am not a very good Julia programmer (despite reading the doc numerous times). For what I am trying to code at the moment, I am trying to create something close to a Python class. I thought of using a mutable struct, …

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## [Setting environment variables for a package "SCIP"](https://discourse.julialang.org/t/setting-environment-variables-for-a-package-scip/43839)

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**Author:** [@mayar](https://discourse.julialang.org/u/mayar)\
**Replies:** 27\
**Last updated:** [July 31, 2020, 9:46pm UTC](https://discourse.julialang.org/t/setting-environment-variables-for-a-package-scip/43839 "2020-07-31T21:46:07Z")

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hello there, I need to set the environment variable for SCIP package I am wokring on windows 10…so I opened: Advanced system Settings…Advanced…Environment Variables I created a new variable and added the path as: C:…

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## [Differential Equations Parameters not recognized when solving in newest packages](https://discourse.julialang.org/t/differential-equations-parameters-not-recognized-when-solving-in-newest-packages/44018)

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**Author:** [@manweic](https://discourse.julialang.org/u/manweic)\
**Replies:** 1\
**Last updated:** [July 31, 2020, 8:58pm UTC](https://discourse.julialang.org/t/differential-equations-parameters-not-recognized-when-solving-in-newest-packages/44018 "2020-07-31T20:58:33Z")

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I’m having trouble with the updated DifferentialEquations Package (v6.15.0) and it’s dependency DiffEqBase (v6.50.9). I was recently working in a previous version Differential Equations (v6.12.0) and DiffEqBase (v6.25.0)…

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## [Array of Arrays times Array is type unstable](https://discourse.julialang.org/t/array-of-arrays-times-array-is-type-unstable/43924)

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**Author:** [@cosmia](https://discourse.julialang.org/u/cosmia)\
**Replies:** 6\
**Last updated:** [July 31, 2020, 8:25pm UTC](https://discourse.julialang.org/t/array-of-arrays-times-array-is-type-unstable/43924 "2020-07-31T20:25:14Z")

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Hi all, I have a code where I need to perform a element by element multiplication of an Array of Arrays a of size X with an Array b of size X. Note that the inner arrays of a are all the same size. In other words, for ev…

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## [Check host port availability](https://discourse.julialang.org/t/check-host-port-availability/44008)

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**Author:** [@martincornejo](https://discourse.julialang.org/u/martincornejo)\
**Replies:** 1\
**Last updated:** [July 31, 2020, 7:26pm UTC](https://discourse.julialang.org/t/check-host-port-availability/44008 "2020-07-31T19:26:37Z")

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Using Sockets, the connect function serves to establish a connection through a TCP socket connect(\[host\], port::Integer) -\> TCPSocket only problem is, if the host is not listening through this port, trying to connect…

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## [Tips for large-ish latent variable model in Turing](https://discourse.julialang.org/t/tips-for-large-ish-latent-variable-model-in-turing/43388)

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**Author:** [@opera\_malenky](https://discourse.julialang.org/u/opera_malenky)\
**Replies:** 3\
**Last updated:** [July 31, 2020, 7:12pm UTC](https://discourse.julialang.org/t/tips-for-large-ish-latent-variable-model-in-turing/43388 "2020-07-31T19:12:54Z")

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Hi - I have a data set (~900 x 120) on which I’m trying to do dimension reduction. Eventually, I want to test some factor mixture models, but right now, I simply want to do a basic factor analysis. The data set isn’t hug…

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## [Collect doesn't terminate](https://discourse.julialang.org/t/collect-doesnt-terminate/43938)

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**Author:** [@sobhan](https://discourse.julialang.org/u/sobhan)\
**Replies:** 7\
**Last updated:** [July 31, 2020, 5:11pm UTC](https://discourse.julialang.org/t/collect-doesnt-terminate/43938 "2020-07-31T17:11:14Z")

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hi i’m trying to normalize(in the db sense) a dictionary{Int8, Vecctor{Float}} but the code never ends d = Dict() for i in 1:100 c = rand(Int8) n = rand() a = get!(d, c, \[\]) push!(a, n) end map(collect, …

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## [Is QuantumLab.jl abandoned?](https://discourse.julialang.org/t/is-quantumlab-jl-abandoned/33136)

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**Author:** [@XVilka](https://discourse.julialang.org/u/XVilka)\
**Replies:** 18\
**Last updated:** [July 31, 2020, 4:51pm UTC](https://discourse.julialang.org/t/is-quantumlab-jl-abandoned/33136 "2020-07-31T16:51:37Z")

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There is a quantum chemistry and physics framework called QuantumLab.jl, but It seems there are no updates for a while, and it doesn’t work with the latest Julia and libraries. Does anyone know if there are any alternat…

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## [Kudos to the VS Code development team](https://discourse.julialang.org/t/kudos-to-the-vs-code-development-team/44049)

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**Author:** [@PetrKryslUCSD](https://discourse.julialang.org/u/PetrKryslUCSD)\
**Replies:** 0\
**Last updated:** [July 31, 2020, 4:32pm UTC](https://discourse.julialang.org/t/kudos-to-the-vs-code-development-team/44049 "2020-07-31T16:32:30Z")

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Just watched David’s presentation. Incredible work, guys!

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## [UndefVarError: parameter\_upper\_bound not defined](https://discourse.julialang.org/t/undefvarerror-parameter-upper-bound-not-defined/43975)

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**Author:** [@goedman](https://discourse.julialang.org/u/goedman)\
**Replies:** 5\
**Last updated:** [July 31, 2020, 4:01pm UTC](https://discourse.julialang.org/t/undefvarerror-parameter-upper-bound-not-defined/43975 "2020-07-31T16:01:40Z")

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Hi, Since about a week or so I often get below message (several of them) when testing in Julia-1.6-DEV. It works fine when using projects but not in the (@v1.6) environment. Is this maybe a change in Pkg? I’m fine work…

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## [Julia v1.5.0-rc2 is now available](https://discourse.julialang.org/t/julia-v1-5-0-rc2-is-now-available/43789)

<div class="topic-metadata">

**Author:** [@ararslan](https://discourse.julialang.org/u/ararslan)\
**Replies:** 17\
**Last updated:** [July 31, 2020, 3:37pm UTC](https://discourse.julialang.org/t/julia-v1-5-0-rc2-is-now-available/43789 "2020-07-31T15:37:07Z")

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Greetings! May I interest you in a fresh, new Julia version to go with your JuliaCon? The second release candidate for Julia v1.5.0 is now available. As usual, binaries for macOS, Windows (32-, 64-bit), macOS (x86-64), …

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## [Emacsclient doesn't work with @edit](https://discourse.julialang.org/t/emacsclient-doesnt-work-with-edit/43673)

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**Author:** [@NightMachinary](https://discourse.julialang.org/u/NightMachinary)\
**Replies:** 8\
**Last updated:** [July 31, 2020, 3:26pm UTC](https://discourse.julialang.org/t/emacsclient-doesnt-work-with-edit/43673 "2020-07-31T15:26:38Z")

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I have tried setting EDITOR and VISUAL to emacsclient -t, and to point to this wrapper: #!/usr/bin/env dash emacsclient -t "$@" But they don’t work. I get this error when I try @edit someFunc(): emacsclient: could no…

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## [New topic "quantum physics" under domains](https://discourse.julialang.org/t/new-topic-quantum-physics-under-domains/43997)

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**Author:** [@Roger-luo](https://discourse.julialang.org/u/Roger-luo)\
**Replies:** 16\
**Last updated:** [July 31, 2020, 2:31pm UTC](https://discourse.julialang.org/t/new-topic-quantum-physics-under-domains/43997 "2020-07-31T14:31:26Z")

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Hi I’m wondering we could have a new topic “quantum physics” under domains. According to today’s Quantum BoF, we find it’s quite inconvenient to find posts related it sometimes given we already have a group of quantum ph…

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## [Pinning package without updating other packages](https://discourse.julialang.org/t/pinning-package-without-updating-other-packages/43900)

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**Author:** [@manweic](https://discourse.julialang.org/u/manweic)\
**Replies:** 8\
**Last updated:** [July 31, 2020, 1:02pm UTC](https://discourse.julialang.org/t/pinning-package-without-updating-other-packages/43900 "2020-07-31T13:02:50Z")

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Hi, I’m building off of someone else’s project, so I use their Manifest and Project files. I want to pin the dependencies to prevent it from breaking in the future. However, when I use the pin command, it installs and u…

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## [Efficient parsing of arrays of arrays of arrays or arbitrary number of arrays of arrays?](https://discourse.julialang.org/t/efficient-parsing-of-arrays-of-arrays-of-arrays-or-arbitrary-number-of-arrays-of-arrays/43972)

<div class="topic-metadata">

**Author:** [@Marcell\_Havlik](https://discourse.julialang.org/u/Marcell_Havlik)\
**Replies:** 7\
**Last updated:** [July 31, 2020, 11:56am UTC](https://discourse.julialang.org/t/efficient-parsing-of-arrays-of-arrays-of-arrays-or-arbitrary-number-of-arrays-of-arrays/43972 "2020-07-31T11:56:04Z")

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Hey Julianers, I parsed a JSON file with JSON2.jl and now I have to postprocess the results it into an Array{Array{Float32, N},1}. The problem is that, the JSON parsed struct is an arrays of arrays of arrays of … and so…

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## [Probably the dumbest question you'll get all day - Proper way to build a julia dev environment](https://discourse.julialang.org/t/probably-the-dumbest-question-youll-get-all-day-proper-way-to-build-a-julia-dev-environment/44014)

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**Author:** [@John\_Antypas](https://discourse.julialang.org/u/John_Antypas)\
**Replies:** 6\
**Last updated:** [July 31, 2020, 11:53am UTC](https://discourse.julialang.org/t/probably-the-dumbest-question-youll-get-all-day-proper-way-to-build-a-julia-dev-environment/44014 "2020-07-31T11:53:29Z")

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I feel so new! Even at my age! But… I’ve been watching Julia for a while and decided it a try on a real application. I come from Scala/Akka, C and C++, and a bunch of ancient languages. Julia has some really nice con…

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## [Promotion for arithmetic operations on @enum types](https://discourse.julialang.org/t/promotion-for-arithmetic-operations-on-enum-types/43881)

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**Author:** [@disberd](https://discourse.julialang.org/u/disberd)\
**Replies:** 8\
**Last updated:** [July 31, 2020, 11:04am UTC](https://discourse.julialang.org/t/promotion-for-arithmetic-operations-on-enum-types/43881 "2020-07-31T11:04:05Z")

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if I have an @enum defined like this: @enum CircPolType RightPol=1 LeftPol=-1, And would like to then uses instances RightPol and LeftPol directly with their integer values in mathematical operations without having to w…

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## [Combining strings](https://discourse.julialang.org/t/combining-strings/44007)

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**Author:** [@bsmith](https://discourse.julialang.org/u/bsmith)\
**Replies:** 4\
**Last updated:** [July 31, 2020, 10:53am UTC](https://discourse.julialang.org/t/combining-strings/44007 "2020-07-31T10:53:49Z")

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Hi, I am trying to process some string data - each element of the array should be split up into individual words and then combined. At the end, I only want the unique words in the array. In R, I would just run a loop an…

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## [Broadcasting not on all arguments](https://discourse.julialang.org/t/broadcasting-not-on-all-arguments/44027)

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**Author:** [@drhouse82](https://discourse.julialang.org/u/drhouse82)\
**Replies:** 1\
**Last updated:** [July 31, 2020, 10:06am UTC](https://discourse.julialang.org/t/broadcasting-not-on-all-arguments/44027 "2020-07-31T10:06:38Z")

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I find myself thinking in common OOP terms and trying to have object representing a model that has some method to do something to outside data. So I thought, in Julia, the model should likely be a struct and the method …

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## [UInt8 access Bits?](https://discourse.julialang.org/t/uint8-access-bits/43990)

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**Author:** [@YoungAlpha](https://discourse.julialang.org/u/YoungAlpha)\
**Replies:** 8\
**Last updated:** [July 31, 2020, 8:40am UTC](https://discourse.julialang.org/t/uint8-access-bits/43990 "2020-07-31T08:40:10Z")

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Hi, guys, is there a way to query or flip specific bits? julia\> binary = 0b111 0x07 julia\> bitstring(binary) "00000111" julia\> typeof(binary) UInt8 In this case the following results would be expected: binary\[1\] ==…

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## [Julia equivalent to R's rep(..., length.out)](https://discourse.julialang.org/t/julia-equivalent-to-rs-rep-length-out/44005)

<div class="topic-metadata">

**Author:** [@kai](https://discourse.julialang.org/u/kai)\
**Replies:** 5\
**Last updated:** [July 31, 2020, 7:48am UTC](https://discourse.julialang.org/t/julia-equivalent-to-rs-rep-length-out/44005 "2020-07-31T07:48:47Z")

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Copy-pasting a slack discussion for people who might need this: Question: Can we add a length\_out feature to the repeat function? In R, I can do rep(1:3, length.out = 4), which gives 1 2 3 1 . It would be cool if repe…

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## [What do ! mean for functions](https://discourse.julialang.org/t/what-do-mean-for-functions/44019)

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**Author:** [@YoungAlpha](https://discourse.julialang.org/u/YoungAlpha)\
**Replies:** 1\
**Last updated:** [July 31, 2020, 6:51am UTC](https://discourse.julialang.org/t/what-do-mean-for-functions/44019 "2020-07-31T06:51:55Z")

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My question is probably relatively basic, but I haven’t found any information about it anywhere. On the performance tips page, some functions have ! and some don’t. What is the meaning of ! and are there other characters…

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## [How to print exceptions with multiple @async tasks](https://discourse.julialang.org/t/how-to-print-exceptions-with-multiple-async-tasks/43992)

<div class="topic-metadata">

**Author:** [@robsmith11](https://discourse.julialang.org/u/robsmith11)\
**Replies:** 0\
**Last updated:** [July 30, 2020, 4:56pm UTC](https://discourse.julialang.org/t/how-to-print-exceptions-with-multiple-async-tasks/43992 "2020-07-30T16:56:34Z")

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Say I have two @async long-running tasks. How can I know if one of them throws an exception? For example, no error message is ever printed from @sync begin @async error() @async while true sleep(1) end end EDIT: …

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## [How to correctly install Julia in Renoir platform?](https://discourse.julialang.org/t/how-to-correctly-install-julia-in-renoir-platform/43756)

<div class="topic-metadata">

**Author:** [@huaiyuli](https://discourse.julialang.org/u/huaiyuli)\
**Replies:** 5\
**Last updated:** [July 30, 2020, 8:20pm UTC](https://discourse.julialang.org/t/how-to-correctly-install-julia-in-renoir-platform/43756 "2020-07-30T20:20:49Z")

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I am using a laptop with AMD Renoir CPU, the operating system is Manjaro under WSL2. Under a simple performance test there appears to be a major performance problem: julia\> versioninfo() Julia Version 1.4.2 Commit 44fa…

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## [DataFrame row to Dict](https://discourse.julialang.org/t/dataframe-row-to-dict/44003)

<div class="topic-metadata">

**Author:** [@Samuel\_Collie](https://discourse.julialang.org/u/Samuel_Collie)\
**Replies:** 5\
**Last updated:** [July 30, 2020, 8:08pm UTC](https://discourse.julialang.org/t/dataframe-row-to-dict/44003 "2020-07-30T20:08:13Z")

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I’d like to query a row of a DataFrame and return the result as a Dict. I was able to do it but the code isn’t pretty (converting Python programmer here). Here is a MWE: Input DataFrame: DataFrame(name=\["John", "Sally"…

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## [Convert Optim objective value back to a Float](https://discourse.julialang.org/t/convert-optim-objective-value-back-to-a-float/43942)

<div class="topic-metadata">

**Author:** [@tyleransom](https://discourse.julialang.org/u/tyleransom)\
**Replies:** 6\
**Last updated:** [July 30, 2020, 7:32pm UTC](https://discourse.julialang.org/t/convert-optim-objective-value-back-to-a-float/43942 "2020-07-30T19:32:16Z")

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I am working with the code in this gist. In the file test\_autochoice\_mew2.jl , I have the following pieces of code: \[...\] T = promote\_type(promote\_type(promote\_type(eltype(X),eltype(b)),eltype(Z)),eltype(W)) \[...\] ℓ …

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## [At a glance, why don't I have better performances between Julia and PHP?](https://discourse.julialang.org/t/at-a-glance-why-dont-i-have-better-performances-between-julia-and-php/43804)

<div class="topic-metadata">

**Author:** [@Darione](https://discourse.julialang.org/u/Darione)\
**Replies:** 24\
**Last updated:** [July 30, 2020, 5:41pm UTC](https://discourse.julialang.org/t/at-a-glance-why-dont-i-have-better-performances-between-julia-and-php/43804 "2020-07-30T17:41:16Z")

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Hi everyone! I manage an automatic warehouse, where there are trays with a certain number of items inside. I was trying to do a count with Julia, elaborating some csv files that I export from my management and that repr…

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