# General Usage

**URL:** https://discourse.julialang.org/c/usage/6.md?page=939

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**Page:** 940

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## [A undocumented breaking change in Julia0.7?](https://discourse.julialang.org/t/a-undocumented-breaking-change-in-julia0-7/15065)

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**Author:** [@Jieyi\_Xiong](https://discourse.julialang.org/u/Jieyi_Xiong)\
**Replies:** 1\
**Last updated:** [September 17, 2018, 7:15pm UTC](https://discourse.julialang.org/t/a-undocumented-breaking-change-in-julia0-7/15065 "2018-09-17T19:15:34Z")

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I found bits(‘A’) in Julia0.7 is “01000001000000000000000000000000”, which is different from Julia0.6 “00000000000000000000000001000001”. However, in both versions, bits(UInt32(‘A’))=“00000000000000000000000001000001”. S…

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## [How to tell if readuntil got a delimiter](https://discourse.julialang.org/t/how-to-tell-if-readuntil-got-a-delimiter/15068)

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**Author:** [@Tamas\_Papp](https://discourse.julialang.org/u/Tamas_Papp)\
**Replies:** 3\
**Last updated:** [September 17, 2018, 7:02pm UTC](https://discourse.julialang.org/t/how-to-tell-if-readuntil-got-a-delimiter/15068 "2018-09-17T19:02:17Z")

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I find that readuntil is very efficient, but in case it reaches EOF, I would like to find a way to verify that it got a delimiter. Eg io = IOBuffer("foo") readuntil(io, ';')) eof(io) # true, but how can I tell there was…

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## [How to debug this broadcast warning about iteration?](https://discourse.julialang.org/t/how-to-debug-this-broadcast-warning-about-iteration/15082)

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**Author:** [@tk3369](https://discourse.julialang.org/u/tk3369)\
**Replies:** 1\
**Last updated:** [September 17, 2018, 6:39pm UTC](https://discourse.julialang.org/t/how-to-debug-this-broadcast-warning-about-iteration/15082 "2018-09-17T18:39:29Z")

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This warning came up on 0.7 but not 1.0 although my code works fine in 1.0. I have two questions: How do I track down where the problem came from? There isn’t any stack trace. If the behavior hasn’t changed then …

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## [Why Julia returns error on myit .+ 1 in the following code?](https://discourse.julialang.org/t/why-julia-returns-error-on-myit-1-in-the-following-code/15021)

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**Author:** [@AdamR](https://discourse.julialang.org/u/AdamR)\
**Replies:** 8\
**Last updated:** [September 17, 2018, 6:22pm UTC](https://discourse.julialang.org/t/why-julia-returns-error-on-myit-1-in-the-following-code/15021 "2018-09-17T18:22:52Z")

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I want to learn the broadcasting, and play with the following type, that mimics the UnitRange type: julia\> struct MyArr m\_begin::NTuple{3, Int32} m\_count::NTuple{3, UInt32} end julia\> myit=MyArr((2,3,4), (3,2,…

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## [IJulia... v.0.6.4, etc](https://discourse.julialang.org/t/ijulia-v-0-6-4-etc/15079)

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**Author:** [@BLI](https://discourse.julialang.org/u/BLI)\
**Replies:** 0\
**Last updated:** [September 17, 2018, 4:20pm UTC](https://discourse.julialang.org/t/ijulia-v-0-6-4-etc/15079 "2018-09-17T16:20:30Z")

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A couple of questions on IJulia/Jypyter Notebook… IJulia problem in v.0.6.4? I just removed Julia v.1.0 from my work desktop, and tried to re-install Julia v.0.6.4… essentially because I need to test some code that c…

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## [Column iterator](https://discourse.julialang.org/t/column-iterator/14967)

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**Author:** [@mschauer](https://discourse.julialang.org/u/mschauer)\
**Replies:** 8\
**Last updated:** [September 17, 2018, 3:07pm UTC](https://discourse.julialang.org/t/column-iterator/14967 "2018-09-17T15:07:58Z")

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I’d like to define a plain iterator over the columns of a matrix in style of julienned arrays. If I take the state to be struct Slice{T} \<: AbstractVector{T} a::Matrix{T} idx::Int end what do I have to define o…

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## [References to variables: When might precompile fail?](https://discourse.julialang.org/t/references-to-variables-when-might-precompile-fail/14965)

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**Author:** [@MA\_Laforge](https://discourse.julialang.org/u/MA_Laforge)\
**Replies:** 2\
**Last updated:** [September 17, 2018, 2:30pm UTC](https://discourse.julialang.org/t/references-to-variables-when-might-precompile-fail/14965 "2018-09-17T14:30:10Z")

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Background After migrating to Julia 1.0, I started having issues with code hanging when it loads (unless I add @show statements to un-jam Julia somehow). I suspect the issue might have been triggered either the by the c…

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## [How to run in 0.7 pkg mode by include() in script ? \] not works!](https://discourse.julialang.org/t/how-to-run-in-0-7-pkg-mode-by-include-in-script-not-works/15067)

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**Author:** [@programista](https://discourse.julialang.org/u/programista)\
**Replies:** 2\
**Last updated:** [September 17, 2018, 2:20pm UTC](https://discourse.julialang.org/t/how-to-run-in-0-7-pkg-mode-by-include-in-script-not-works/15067 "2018-09-17T14:20:53Z")

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in 0.7 key “\]” is starting Pkg mode… How to run this mode from script by include(“script.jl” ) ? After usingn script \] is ERROR: LoadError: syntax: unexpected “\]” Paul

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## [how to zoom in the Plots in the Atom Plots Panel](https://discourse.julialang.org/t/how-to-zoom-in-the-plots-in-the-atom-plots-panel/15064)

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**Author:** [@phystry](https://discourse.julialang.org/u/phystry)\
**Replies:** 1\
**Last updated:** [September 17, 2018, 12:57pm UTC](https://discourse.julialang.org/t/how-to-zoom-in-the-plots-in-the-atom-plots-panel/15064 "2018-09-17T12:57:19Z")

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Really small plots display or can i make the plots in another new window using gui() could not work for the default Plots package !

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## [Iterating array like numpy?](https://discourse.julialang.org/t/iterating-array-like-numpy/15059)

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**Author:** [@xiang0x48](https://discourse.julialang.org/u/xiang0x48)\
**Replies:** 1\
**Last updated:** [September 17, 2018, 12:05pm UTC](https://discourse.julialang.org/t/iterating-array-like-numpy/15059 "2018-09-17T12:05:29Z")

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Julia seems broadcast/iterate array by elements: arr = zeros(Float32, 3, 2) for x in arr println(x) end # output 6 lines of 0.0 I’m wondering if we can iterate normal arrays like numpy fashion, thus can we have: arr =…

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## [Backward substitution without memory allocation (Julia v0.6)](https://discourse.julialang.org/t/backward-substitution-without-memory-allocation-julia-v0-6/15060)

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**Author:** [@migarstka](https://discourse.julialang.org/u/migarstka)\
**Replies:** 0\
**Last updated:** [September 17, 2018, 11:57am UTC](https://discourse.julialang.org/t/backward-substitution-without-memory-allocation-julia-v0-6/15060 "2018-09-17T11:57:39Z")

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Let’s say I have a sparse positive semidefinite matrix that I want to factor using ldltfact and then solve a system of equations with changing right hand sides. Is there any way to do this without allocating new memory …

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## [Disk quota exceeded](https://discourse.julialang.org/t/disk-quota-exceeded/15039)

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**Author:** [@jonjilla](https://discourse.julialang.org/u/jonjilla)\
**Replies:** 2\
**Last updated:** [September 17, 2018, 8:32am UTC](https://discourse.julialang.org/t/disk-quota-exceeded/15039 "2018-09-17T08:32:13Z")

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Hello, I’m getting this error now in the REPL I have plenty of disk space in the current directory and the install directory. Where should I look to see where I am running out of disk space? \\u250c Error: Error in th…

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## [Specify version range with specific versions in \[compat\] on 0.7/1.0?](https://discourse.julialang.org/t/specify-version-range-with-specific-versions-in-compat-on-0-7-1-0/15018)

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**Author:** [@Sukera](https://discourse.julialang.org/u/Sukera)\
**Replies:** 5\
**Last updated:** [September 17, 2018, 8:02am UTC](https://discourse.julialang.org/t/specify-version-range-with-specific-versions-in-compat-on-0-7-1-0/15018 "2018-09-17T08:02:36Z")

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Is it possible to specify a version range in the \[compat\] section in Project.toml? In particular, I’d like to specify a range including both 0.7 and 1.0, indicating that the package works for all versions from 0.7 to 1,…

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## [Terminating sum early](https://discourse.julialang.org/t/terminating-sum-early/15012)

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**Author:** [@Tamas\_Papp](https://discourse.julialang.org/u/Tamas_Papp)\
**Replies:** 14\
**Last updated:** [September 17, 2018, 7:23am UTC](https://discourse.julialang.org/t/terminating-sum-early/15012 "2018-09-17T07:23:33Z")

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I am calculating a sum of values returned by a function, which is supposed to be type stable. The function may be costly, and returns values that are either finite or -Inf. In case of -Inf, I would like to return early. …

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## [Multiple levels of debug logging](https://discourse.julialang.org/t/multiple-levels-of-debug-logging/15048)

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**Author:** [@tk3369](https://discourse.julialang.org/u/tk3369)\
**Replies:** 1\
**Last updated:** [September 17, 2018, 6:14am UTC](https://discourse.julialang.org/t/multiple-levels-of-debug-logging/15048 "2018-09-17T06:14:52Z")

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The new Logging utility is very nice. However, for debug logging, I often want to have several levels of verbosity e.g. Level 1 - function entry point Level 2 - debug within function body Level 3 - debug within some …

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## [Profile segfault](https://discourse.julialang.org/t/profile-segfault/13484)

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**Author:** [@jstrube](https://discourse.julialang.org/u/jstrube)\
**Replies:** 5\
**Last updated:** [September 16, 2018, 9:12pm UTC](https://discourse.julialang.org/t/profile-segfault/13484 "2018-09-16T21:12:33Z")

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I’m porting some particle physics code (Fox Wolfram moments) to Julia. The first attempt had pretty awful performance, so I’m trying to figure out the bottle necks. Unfortunately, profile barfs (trace below). This code…

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## [Type-dependent generation of Channels on workers](https://discourse.julialang.org/t/type-dependent-generation-of-channels-on-workers/15033)

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**Author:** [@Sean\_McBane](https://discourse.julialang.org/u/Sean_McBane)\
**Replies:** 0\
**Last updated:** [September 16, 2018, 8:42pm UTC](https://discourse.julialang.org/t/type-dependent-generation-of-channels-on-workers/15033 "2018-09-16T20:42:20Z")

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Hi all, I want to write some parallel library code that works on generic types; for this purpose I want to create RemoteChannels between processes with a particular type for passing data back and forth. They need to be …

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## [0.7.0 Dates: how to dsipaly only values , without "days" for diff()?](https://discourse.julialang.org/t/0-7-0-dates-how-to-dsipaly-only-values-without-days-for-diff/15028)

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**Author:** [@programista](https://discourse.julialang.org/u/programista)\
**Replies:** 4\
**Last updated:** [September 16, 2018, 7:30pm UTC](https://discourse.julialang.org/t/0-7-0-dates-how-to-dsipaly-only-values-without-days-for-diff/15028 "2018-09-16T19:30:21Z")

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0.7.0 Dates: how to dsipaly only values , without “days” for diff() ? (diff(daty)).value not works. julia\> (Date.(dane\[1,1\])-Date.(dane\[4,1\])).value -90 julia\> (diff(daty)).value ERROR: type Array has no field value …

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## [Why \`@code\_lowered (1,2,3) .+ 1\` returns error?](https://discourse.julialang.org/t/why-code-lowered-1-2-3-1-returns-error/15019)

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**Author:** [@AdamR](https://discourse.julialang.org/u/AdamR)\
**Replies:** 3\
**Last updated:** [September 16, 2018, 4:19pm UTC](https://discourse.julialang.org/t/why-code-lowered-1-2-3-1-returns-error/15019 "2018-09-16T16:19:20Z")

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\_ \_ \_ \_(\_)\_ | Documentation: https://docs.julialang.org (\_) | (\_) (\_) | \_ \_ \_| |\_ \_\_ \_ | Type "?" for help, "\]?" for Pkg help. | | | | | | |/ \_\` | | | | |\_| | | | (\_| |…

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## [Sparse broadcasting division with a dense vector yields a dense array](https://discourse.julialang.org/t/sparse-broadcasting-division-with-a-dense-vector-yields-a-dense-array/15005)

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**Author:** [@mboratko](https://discourse.julialang.org/u/mboratko)\
**Replies:** 3\
**Last updated:** [September 16, 2018, 12:30pm UTC](https://discourse.julialang.org/t/sparse-broadcasting-division-with-a-dense-vector-yields-a-dense-array/15005 "2018-09-16T12:30:49Z")

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Here is an example of the issue: julia\> using SparseArrays julia\> test = spzeros(4,4) 4×4 SparseMatrixCSC{Float64,Int64} with 0 stored entries julia\> test\[2,2\]=4 4 julia\> test ./ 2 4×4 SparseMatrixCSC{Float64,Int64} …

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## [Syntax issue in MAT package](https://discourse.julialang.org/t/syntax-issue-in-mat-package/14843)

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**Author:** [@Caesar\_KG](https://discourse.julialang.org/u/Caesar_KG)\
**Replies:** 5\
**Last updated:** [September 16, 2018, 4:32am UTC](https://discourse.julialang.org/t/syntax-issue-in-mat-package/14843 "2018-09-16T04:32:33Z")

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In the MAT\_v5.jl of MAT Package, I’ve seen the following definition type Matlabv5File \<: HDF5.DataFile ios::IOStream swap\_bytes::Bool varnames::Dict{String, Int64} Matlabv5File(ios, swap\_bytes) = new(ios, swap\_bytes…

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## [Background processes in julia](https://discourse.julialang.org/t/background-processes-in-julia/11596)

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**Author:** [@00vareladavid](https://discourse.julialang.org/u/00vareladavid)\
**Replies:** 3\
**Last updated:** [September 16, 2018, 12:28am UTC](https://discourse.julialang.org/t/background-processes-in-julia/11596 "2018-09-16T00:28:02Z")

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I’m porting some bash code to julia but I’m not sure the best way to create background processes in julia. My bash code is something like: func1 & func2 & wait This will start func1 and func2 concurrently. I saw that …

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## ['using MyModule' is costly](https://discourse.julialang.org/t/using-mymodule-is-costly/14984)

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**Author:** [@LeoK987](https://discourse.julialang.org/u/LeoK987)\
**Replies:** 6\
**Last updated:** [September 15, 2018, 2:49pm UTC](https://discourse.julialang.org/t/using-mymodule-is-costly/14984 "2018-09-15T14:49:57Z")

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See my experiments below: $ julia \_ \_ \_ \_(\_)\_ | Documentation: https://docs.julialang.org (\_) | (\_) (\_) | \_ \_ \_| |\_ \_\_ \_ | Type "?" for help, "\]?" for Pkg help. | | | | |…

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## [Julia 1.0 add JLD Error](https://discourse.julialang.org/t/julia-1-0-add-jld-error/13632)

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**Author:** [@programista](https://discourse.julialang.org/u/programista)\
**Replies:** 12\
**Last updated:** [September 15, 2018, 2:42pm UTC](https://discourse.julialang.org/t/julia-1-0-add-jld-error/13632 "2018-09-15T14:42:15Z")

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\_ \_ \_ ()\_ | Documentation: https://docs.julialang.org () | () () | \_ \_ | | \_\_ \_ | Type “?” for help, “\]?” for Pkg help. | | | | | | |/ \` | | | | || | | | (| | | Version 1.0.0 (2…

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## [Multiplication of rational by an integer](https://discourse.julialang.org/t/multiplication-of-rational-by-an-integer/14991)

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**Author:** [@Pavel\_Kalouguine](https://discourse.julialang.org/u/Pavel_Kalouguine)\
**Replies:** 0\
**Last updated:** [September 15, 2018, 9:08am UTC](https://discourse.julialang.org/t/multiplication-of-rational-by-an-integer/14991 "2018-09-15T09:08:43Z")

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When profiling some Julia code I stumbled upon an unexpected performance bottleneck at the line corresponding to multiplication of a static matrix of integers and a static vector of rationals. Further investigation revea…

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## [Defining a custom iterator that wraps multiple iterators](https://discourse.julialang.org/t/defining-a-custom-iterator-that-wraps-multiple-iterators/14790)

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**Author:** [@schmrlng](https://discourse.julialang.org/u/schmrlng)\
**Replies:** 5\
**Last updated:** [September 15, 2018, 2:01am UTC](https://discourse.julialang.org/t/defining-a-custom-iterator-that-wraps-multiple-iterators/14790 "2018-09-15T02:01:04Z")

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I’m having a tough time writing performant iterators that wrap multiple other iterators; as an illustrative example this is how I would currently write a simple merge sort iterator: struct MergeSortIterator{I1,I2} a…

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## [LD\_LOAD\_PATH syntax](https://discourse.julialang.org/t/ld-load-path-syntax/14981)

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**Author:** [@Gregory\_Martinez](https://discourse.julialang.org/u/Gregory_Martinez)\
**Replies:** 1\
**Last updated:** [September 14, 2018, 11:40pm UTC](https://discourse.julialang.org/t/ld-load-path-syntax/14981 "2018-09-14T23:40:56Z")

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What is the syntax for specifying a load\_path to the linker in Julia. It used to be push!(DL\_LOAD\_PATH, "/path") But this doesn’t work anymore

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## [Plot size in Juno](https://discourse.julialang.org/t/plot-size-in-juno/14959)

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**Author:** [@Christopher\_Fisher](https://discourse.julialang.org/u/Christopher_Fisher)\
**Replies:** 3\
**Last updated:** [September 14, 2018, 9:21pm UTC](https://discourse.julialang.org/t/plot-size-in-juno/14959 "2018-09-14T21:21:57Z")

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Hi all- For some reason, plots in Plots.jl are showing up very small in Juno/Atom plot panel (about 10% of the panel). Is there a way to change the size? Thanks.

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## [Weird (and wrong) paths shown for source files in Julia 0.7 under Windows](https://discourse.julialang.org/t/weird-and-wrong-paths-shown-for-source-files-in-julia-0-7-under-windows/10782)

<div class="topic-metadata">

**Author:** [@digital\_carver](https://discourse.julialang.org/u/digital_carver)\
**Replies:** 5\
**Last updated:** [September 14, 2018, 4:34pm UTC](https://discourse.julialang.org/t/weird-and-wrong-paths-shown-for-source-files-in-julia-0-7-under-windows/10782 "2018-09-14T16:34:20Z")

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I just downloaded and installed the Julia 0.7.0 nightly build for Windows. Something seems to have gone wonky with the installation though, since the paths Julia REPL messages output are weird non-existent ones. julia\> …

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## [Understanding eval](https://discourse.julialang.org/t/understanding-eval/14926)

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**Author:** [@rcnlee](https://discourse.julialang.org/u/rcnlee)\
**Replies:** 6\
**Last updated:** [September 14, 2018, 4:15pm UTC](https://discourse.julialang.org/t/understanding-eval/14926 "2018-09-14T16:15:19Z")

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I’m trying to understand why there is such a performance difference calling eval vs. just typing it in. The difference doesn’t depend on whether the expression depends on any variables. How can I make the eval version …

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