# Latest

**URL:** https://discourse.julialang.org/latest.md?page=1988

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

**Page:** 1989

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## [DataFramesMeta custom filter: by groups of A, apply filter on B](https://discourse.julialang.org/t/dataframesmeta-custom-filter-by-groups-of-a-apply-filter-on-b/24557)

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**Author:** [@floswald](https://discourse.julialang.org/u/floswald)\
**Replies:** 4\
**Last updated:** [May 27, 2019, 6:44pm UTC](https://discourse.julialang.org/t/dataframesmeta-custom-filter-by-groups-of-a-apply-filter-on-b/24557 "2019-05-27T18:44:08Z")

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I need to subset a dataframe by groups. that is, in each group there is a different filtering condition to apply. here is a MWE using DataFrames, DataFramesMeta julia\> df = DataFrame(A = repeat(1:3,3), B = rand(1:9,9),…

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## [DataDeps post\_fetch\_method](https://discourse.julialang.org/t/datadeps-post-fetch-method/24649)

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**Author:** [@yakir12](https://discourse.julialang.org/u/yakir12)\
**Replies:** 6\
**Last updated:** [May 27, 2019, 4:52pm UTC](https://discourse.julialang.org/t/datadeps-post-fetch-method/24649 "2019-05-27T16:52:26Z")

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I have a bunch of zipped .csv files on an S3 repo. I’m using the excellent DataDeps to retrieve them. Next, I use the also excellent JuliaDB to loadtable the .csvs into tables, and then from there it’s processing etc etc…

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## [Workflow question - how to guarantee no dependence on global state without long load times?](https://discourse.julialang.org/t/workflow-question-how-to-guarantee-no-dependence-on-global-state-without-long-load-times/24613)

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**Author:** [@Nathaniel](https://discourse.julialang.org/u/Nathaniel)\
**Replies:** 19\
**Last updated:** [May 27, 2019, 11:36am UTC](https://discourse.julialang.org/t/workflow-question-how-to-guarantee-no-dependence-on-global-state-without-long-load-times/24613 "2019-05-27T11:36:30Z")

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This is a question about workflow. I like to code in an exploratory, iterative way, but I generally prefer not to use REPL or notebook environments, because I like to keep everything in a state where even if I get interr…

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## [Delete rows that exist in another data frame in Julia?](https://discourse.julialang.org/t/delete-rows-that-exist-in-another-data-frame-in-julia/24645)

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**Author:** [@Luigi\_Marongiu](https://discourse.julialang.org/u/Luigi_Marongiu)\
**Replies:** 1\
**Last updated:** [May 27, 2019, 11:06am UTC](https://discourse.julialang.org/t/delete-rows-that-exist-in-another-data-frame-in-julia/24645 "2019-05-27T11:06:43Z")

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Dear all, how can I remove the row of a dataframe whose selected column matches the value of another dataframe? essentially, is there an equivalent of R’s %in% operator in Julia? Thanks

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## [Julia appending data to dataframe gives dataframe not defined](https://discourse.julialang.org/t/julia-appending-data-to-dataframe-gives-dataframe-not-defined/24644)

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**Author:** [@Luigi\_Marongiu](https://discourse.julialang.org/u/Luigi_Marongiu)\
**Replies:** 1\
**Last updated:** [May 27, 2019, 11:04am UTC](https://discourse.julialang.org/t/julia-appending-data-to-dataframe-gives-dataframe-not-defined/24644 "2019-05-27T11:04:01Z")

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Dear all, I am trying to append data to a data frame. I have set an empty dataframe, then made a copy of it, the point is in populate the data frame and rest it by re-copying the empty one. By doing this reiterate, I sa…

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## [Weave how to print markdown in for loop?](https://discourse.julialang.org/t/weave-how-to-print-markdown-in-for-loop/24643)

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**Author:** [@Wikunia](https://discourse.julialang.org/u/Wikunia)\
**Replies:** 6\
**Last updated:** [May 27, 2019, 10:30am UTC](https://discourse.julialang.org/t/weave-how-to-print-markdown-in-for-loop/24643 "2019-05-27T10:30:07Z")

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I currently trying to use GitHub - JunoLab/Weave.jl: Scientific reports/literate programming for Julia but not really getting my head around its usage. In general I need more examples of the usage of julia markdown. My…

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## [Debugging with Juno (multiple restarts necessary to make code changes debuggable)](https://discourse.julialang.org/t/debugging-with-juno-multiple-restarts-necessary-to-make-code-changes-debuggable/24427)

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**Author:** [@Volker](https://discourse.julialang.org/u/Volker)\
**Replies:** 8\
**Last updated:** [May 27, 2019, 10:25am UTC](https://discourse.julialang.org/t/debugging-with-juno-multiple-restarts-necessary-to-make-code-changes-debuggable/24427 "2019-05-27T10:25:48Z")

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Hello, I use Julia v1.1, Atom 1.37.0 x64, Juno 0.8.3. under Windows 10. Sometimes when try to debug my code Juno doesn´t recognize my code or the code changes I have made. So that I have to restart Julia relatively oft…

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## [How do I calculate percentiles/IQR with julia?](https://discourse.julialang.org/t/how-do-i-calculate-percentiles-iqr-with-julia/24635)

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**Author:** [@Luigi\_Marongiu](https://discourse.julialang.org/u/Luigi_Marongiu)\
**Replies:** 7\
**Last updated:** [May 27, 2019, 10:08am UTC](https://discourse.julialang.org/t/how-do-i-calculate-percentiles-iqr-with-julia/24635 "2019-05-27T10:08:47Z")

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Hello, I would like to find the percentile and interquartile range of a column of a dataframe. I have loaded both Statistics and StatsBase, but when I try iqr(N\[:column\]) I get: ERROR: MethodError: no method matching …

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## [Save complete session snapshot?](https://discourse.julialang.org/t/save-complete-session-snapshot/24537)

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**Author:** [@pablosanjose](https://discourse.julialang.org/u/pablosanjose)\
**Replies:** 11\
**Last updated:** [May 27, 2019, 8:29am UTC](https://discourse.julialang.org/t/save-complete-session-snapshot/24537 "2019-05-27T08:29:07Z")

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I keep wondering why the time-to-first-whatever is such a difficult problem. It is currently my main issue with Julia by a fair margin (I do know about Revise and PackageCompiler, but also about their limitations). There…

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## [What is the meaning of Base.Order.ForwardOrdering?](https://discourse.julialang.org/t/what-is-the-meaning-of-base-order-forwardordering/24640)

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**Author:** [@bsnyh](https://discourse.julialang.org/u/bsnyh)\
**Replies:** 1\
**Last updated:** [May 27, 2019, 8:14am UTC](https://discourse.julialang.org/t/what-is-the-meaning-of-base-order-forwardordering/24640 "2019-05-27T08:14:31Z")

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In my task, I need to write code to create a mutable struct with name Si, which has an attribute with name eventQueue, which is of type PriorityQueue. After playing with the code, the following works out well. using Dat…

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## [Juno Julia Path Setting and Open File Dialog](https://discourse.julialang.org/t/juno-julia-path-setting-and-open-file-dialog/24639)

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**Author:** [@student](https://discourse.julialang.org/u/student)\
**Replies:** 1\
**Last updated:** [May 27, 2019, 8:13am UTC](https://discourse.julialang.org/t/juno-julia-path-setting-and-open-file-dialog/24639 "2019-05-27T08:13:16Z")

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I am new to Julia and wanted to try it out together with Juno IDE for my small experiments. The Atom UI looks very different from what one would used to have for a standalone app GUI. What struck me for example is the …

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## [Evaluation speed during debugging](https://discourse.julialang.org/t/evaluation-speed-during-debugging/24520)

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**Author:** [@Volker](https://discourse.julialang.org/u/Volker)\
**Replies:** 13\
**Last updated:** [May 27, 2019, 7:49am UTC](https://discourse.julialang.org/t/evaluation-speed-during-debugging/24520 "2019-05-27T07:49:18Z")

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Hello, During debugging with Julia v1.1, Atom 1.37.0 x64, Juno 0.8.3 and the latest Rebugger,Debugger, Revise and JulianInterpreter packages. I have noticed that a snippet of my code takes really long (several minutes) …

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## [ANN: 2FA required for JuliaLang GitHub org](https://discourse.julialang.org/t/ann-2fa-required-for-julialang-github-org/24441)

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**Author:** [@StefanKarpinski](https://discourse.julialang.org/u/StefanKarpinski)\
**Replies:** 3\
**Last updated:** [May 27, 2019, 6:27am UTC](https://discourse.julialang.org/t/ann-2fa-required-for-julialang-github-org/24441 "2019-05-27T06:27:10Z")

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We sent emails about a year ago warning that we were going to require 2FA (two factor authentication) for membership in the JuliaLang GitHub organization and all its repos. Today I flipped the switch, which means that an…

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## [Allowing arguments on many places in function name](https://discourse.julialang.org/t/allowing-arguments-on-many-places-in-function-name/24617)

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**Author:** [@baggepinnen](https://discourse.julialang.org/u/baggepinnen)\
**Replies:** 2\
**Last updated:** [May 27, 2019, 2:12am UTC](https://discourse.julialang.org/t/allowing-arguments-on-many-places-in-function-name/24617 "2019-05-27T02:12:48Z")

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Here’s a goofy topic for a rainy Sunday. I was pondering this morning how it would look if a function could accept arguments in more than one place, like the following (needle)occursin(haystack) rather than the current …

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## [Call function every N seconds](https://discourse.julialang.org/t/call-function-every-n-seconds/24611)

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**Author:** [@dfdx](https://discourse.julialang.org/u/dfdx)\
**Replies:** 10\
**Last updated:** [May 26, 2019, 11:02pm UTC](https://discourse.julialang.org/t/call-function-every-n-seconds/24611 "2019-05-26T23:02:40Z")

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In Julia 1.x, is there a way to call a function every N seconds? Some details: reasonable delays in function calls are ok no task cooperation can be assumed, caller is allowed to run entirely within a single task witho…

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## [Matching method argument types in Macro](https://discourse.julialang.org/t/matching-method-argument-types-in-macro/24626)

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**Author:** [@fraxx001](https://discourse.julialang.org/u/fraxx001)\
**Replies:** 3\
**Last updated:** [May 26, 2019, 10:58pm UTC](https://discourse.julialang.org/t/matching-method-argument-types-in-macro/24626 "2019-05-26T22:58:05Z")

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Iam trying to build a macro for chaining operations which works like follow: @chain vec |\> map(x -\> x^2) |\> reduce(+, 0) |\> first(6) The macro should be able to paste the result of the evaluation of a chain element int…

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## [Up to Date Julia Documentation in PDF?](https://discourse.julialang.org/t/up-to-date-julia-documentation-in-pdf/24625)

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**Author:** [@dlakelan](https://discourse.julialang.org/u/dlakelan)\
**Replies:** 2\
**Last updated:** [May 26, 2019, 8:47pm UTC](https://discourse.julialang.org/t/up-to-date-julia-documentation-in-pdf/24625 "2019-05-26T20:47:49Z")

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I want to get a Julia manual in PDF form so I can read it on a plane in a couple days. I see this: https://juliacomputing.com/docs/JuliaDocumentation.pdf but it’s dated Nov 2017 which is a year and half out of date… On …

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## [Plots: Only one series as primary plot](https://discourse.julialang.org/t/plots-only-one-series-as-primary-plot/24616)

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**Author:** [@baggepinnen](https://discourse.julialang.org/u/baggepinnen)\
**Replies:** 17\
**Last updated:** [May 26, 2019, 3:31pm UTC](https://discourse.julialang.org/t/plots-only-one-series-as-primary-plot/24616 "2019-05-26T15:31:47Z")

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I frequently make figures that look like this m = randn(100) n = m .+ randn(100,50) plot(m, lab="mean", l=(5,)) plot!(n; lab="realizations", l=(:black, 0.1)) Here, I would prefer to only have one of the “realizations…

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## [How to avoid the 2 allocations for any struct?](https://discourse.julialang.org/t/how-to-avoid-the-2-allocations-for-any-struct/24590)

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**Author:** [@Jean\_Michel](https://discourse.julialang.org/u/Jean_Michel)\
**Replies:** 21\
**Last updated:** [May 26, 2019, 10:15am UTC](https://discourse.julialang.org/t/how-to-avoid-the-2-allocations-for-any-struct/24590 "2019-05-26T10:15:03Z")

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I illustrate my problem with an example. Say I work heavily with small permutations (elements of the symmetric group) and want to multiply them as fast as possible. A permutation of 1:n is just given by giving the imag…

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## [Copyright question: DrWatson](https://discourse.julialang.org/t/copyright-question-drwatson/24562)

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**Author:** [@Datseris](https://discourse.julialang.org/u/Datseris)\
**Replies:** 8\
**Last updated:** [May 25, 2019, 11:38pm UTC](https://discourse.julialang.org/t/copyright-question-drwatson/24562 "2019-05-25T23:38:42Z")

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Hello! (I didn’t know exactly where to post this, please move it to appropriate section if need be) So I have been developing a Julia software, called DrWatson which is a scientific project assistant. I recently prese…

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## [Custom types in ForwardDiff](https://discourse.julialang.org/t/custom-types-in-forwarddiff/24610)

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**Author:** [@tamasgal](https://discourse.julialang.org/u/tamasgal)\
**Replies:** 8\
**Last updated:** [May 25, 2019, 9:06pm UTC](https://discourse.julialang.org/t/custom-types-in-forwarddiff/24610 "2019-05-25T21:06:21Z")

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This might be trivial but I am currently fighting with JuMP to accept my quality function for the minimisation procedure. I figured out that my custom type: struct Position \<: FieldVector{3, Float64} x::Float64 …

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## [Code review for first serious piece of Julia code](https://discourse.julialang.org/t/code-review-for-first-serious-piece-of-julia-code/24577)

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**Author:** [@ludoro](https://discourse.julialang.org/u/ludoro)\
**Replies:** 8\
**Last updated:** [May 25, 2019, 7:21pm UTC](https://discourse.julialang.org/t/code-review-for-first-serious-piece-of-julia-code/24577 "2019-05-25T19:21:18Z")

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Hello everyone! I am Ludovico. I have been accepted to the Julia season of contribution, and during the community bonding time I started to tackle the first part of my proposal. I am building a new package called “Surro…

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## [Starting Juliavia bat file with new var ? C:\\Users\\PC\\AppData\\Local\\Julia-0.7.0\\bin\\julia.exe -E, a=5?](https://discourse.julialang.org/t/starting-juliavia-bat-file-with-new-var-c-users-pc-appdata-local-julia-0-7-0-bin-julia-exe-e-a-5/24609)

<div class="topic-metadata">

**Author:** [@programista](https://discourse.julialang.org/u/programista)\
**Replies:** 0\
**Last updated:** [May 25, 2019, 7:14pm UTC](https://discourse.julialang.org/t/starting-juliavia-bat-file-with-new-var-c-users-pc-appdata-local-julia-0-7-0-bin-julia-exe-e-a-5/24609 "2019-05-25T19:14:59Z")

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Win I am starting Julia by bat file included: C:\\Users\\PC\\AppData\\Local\\Julia-0.7.0\\bin\\julia.exe Is OK Now I need on the start from operating send any var i.e a=5 anyway … I find switcher E. C:\\Users\\PC\\AppData\\Loc…

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## [Avoid intermediate arrays in reduction of broadcast](https://discourse.julialang.org/t/avoid-intermediate-arrays-in-reduction-of-broadcast/24608)

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**Author:** [@e3c6](https://discourse.julialang.org/u/e3c6)\
**Replies:** 11\
**Last updated:** [May 25, 2019, 6:48pm UTC](https://discourse.julialang.org/t/avoid-intermediate-arrays-in-reduction-of-broadcast/24608 "2019-05-25T18:48:38Z")

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I have some code that looks like this: A = randn(5,4,2) B = randn(5,1,1) C = zeros(5,4,1) sum!(C, A .\* B) # avoid forming \`A.\*B\` ? Is there a simple way to avoid forming the intermediate array A.\*B? I was looking into…

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## [How to create a priority queue with a certain type of key and priority?](https://discourse.julialang.org/t/how-to-create-a-priority-queue-with-a-certain-type-of-key-and-priority/24604)

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**Author:** [@bsnyh](https://discourse.julialang.org/u/bsnyh)\
**Replies:** 1\
**Last updated:** [May 25, 2019, 4:47pm UTC](https://discourse.julialang.org/t/how-to-create-a-priority-queue-with-a-certain-type-of-key-and-priority/24604 "2019-05-25T16:47:24Z")

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mutable struct Event time::Float64 Event = new(-1.0) end create a priority queue with keys of type Event and priorities of type Float64 pq = PriorityQueue(Event, Float64) Then, I got the following error. "Me…

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## [How much of a difference does avoiding allocations make?](https://discourse.julialang.org/t/how-much-of-a-difference-does-avoiding-allocations-make/24585)

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**Author:** [@jules](https://discourse.julialang.org/u/jules)\
**Replies:** 15\
**Last updated:** [May 25, 2019, 1:44pm UTC](https://discourse.julialang.org/t/how-much-of-a-difference-does-avoiding-allocations-make/24585 "2019-05-25T13:44:16Z")

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I was wondering how much use it is to try and prohibit allocations in different scenarios. One case that came to mind was taking the median of many equally sized arrays. I was doing this with an array of arrays: medians…

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## [CSV mmap error when parsing large file](https://discourse.julialang.org/t/csv-mmap-error-when-parsing-large-file/24555)

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**Author:** [@greg\_plowman](https://discourse.julialang.org/u/greg_plowman)\
**Replies:** 6\
**Last updated:** [May 25, 2019, 10:43am UTC](https://discourse.julialang.org/t/csv-mmap-error-when-parsing-large-file/24555 "2019-05-25T10:43:42Z")

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I’m trying to read a large csv file, one row at a time. I want to do something like: using CSV csvFile = CSV.File(infile) for row in csvFile # do stuff with row end However, on Windows 10, Julia v1.1.1, I’m gettin…

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## [Build errors at CI](https://discourse.julialang.org/t/build-errors-at-ci/24595)

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**Author:** [@leiteiro](https://discourse.julialang.org/u/leiteiro)\
**Replies:** 3\
**Last updated:** [May 25, 2019, 8:03am UTC](https://discourse.julialang.org/t/build-errors-at-ci/24595 "2019-05-25T08:03:12Z")

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Since Julia 1.1.1 the builds on appveyor and travis don’t work. For example on appveyor the build yields: Build started git clone -q --branch=master … git checkout -qf … Running Install scripts iex ((new-object net…

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## [Appearance of log axis in Plots](https://discourse.julialang.org/t/appearance-of-log-axis-in-plots/24553)

<div class="topic-metadata">

**Author:** [@Nathaniel](https://discourse.julialang.org/u/Nathaniel)\
**Replies:** 5\
**Last updated:** [May 25, 2019, 7:13am UTC](https://discourse.julialang.org/t/appearance-of-log-axis-in-plots/24553 "2019-05-25T07:13:31Z")

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In Plots, using xaxis=:log, I get evenly spaced tick marks, like this: However, in my case I would much prefer unevenly spaced tickmarks representing uniform intervals, as in this image generated with matplotlib: I…

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## [Complicated type question](https://discourse.julialang.org/t/complicated-type-question/24582)

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**Author:** [@atteson](https://discourse.julialang.org/u/atteson)\
**Replies:** 1\
**Last updated:** [May 25, 2019, 6:38am UTC](https://discourse.julialang.org/t/complicated-type-question/24582 "2019-05-25T06:38:20Z")

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I’d like to define some types similar to the following simplified types. However, since T3’s type is determined by U, I’d rather not have to specify T when writing its type. Is there a way to do this? abstract type T1…

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