# Excellent cheat-sheet

**URL:** <https://discourse.julialang.org/t/excellent-cheat-sheet/7792>\
**Category:** Community\
**Tags:** cheatsheets\
**Created:** [December 15, 2017, 4:27pm UTC](https://discourse.julialang.org/t/excellent-cheat-sheet/7792 "2017-12-15T16:27:08Z")\
**Posts on this page:** 18\
**Page:** 2

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**Author:** ![nickeubank](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/nickeubank/32/3878_2.png) [@nickeubank](https://discourse.julialang.org/u/nickeubank)\
**Post date:** [December 16, 2017, 7:44pm UTC](https://discourse.julialang.org/t/excellent-cheat-sheet/7792/21 "2017-12-16T19:44:50Z")

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> [@kristoffer.carlsson](#):
>
> Immutable types are passed around by value (i.e. copying), whereas mutable types are passed by reference.
> 
> I’m not sure this is really true. Since you can’t modify an immutable struct it doesn’t matter if you copy it or not to pass it as an argument, and the compiler can chose what to do. Also, I don’t think there is anything called “pass by reference” in Julia. What I think it is typically called is “pass by value” and this is true both for mutables and immutables.

[Edit: got correct quote this time]

Happy to change, but I’ll confess I’m a little confused, as this is what’s in the Julia official docs:

 ![53 PM](https://global.discourse-cdn.com/julialang/original/3X/6/8/68ba3df24a7af43b315625589b2fd9d1717e2968.png)

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<div class="post-metadata">

**Author:** ![nickeubank](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/nickeubank/32/3878_2.png) [@nickeubank](https://discourse.julialang.org/u/nickeubank)\
**Post date:** [December 16, 2017, 8:12pm UTC](https://discourse.julialang.org/t/excellent-cheat-sheet/7792/22 "2017-12-16T20:12:16Z")

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@kristoffer.carlsson and @Elrod : OK, think I addressed most of these in [this PR](https://github.com/brakmic/Julia-Cheat-Sheet/pull/8). Few followups:

> [@kristoffer.carlsson](#):
>
> Free up memory for large arrays with arr = nothing

That’s not true in interactive programming, unfortunately, which I know some of us still use.

> [@kristoffer.carlsson](#):
>
> Moreover, using only loads exported names by default while import loads all names defined in the module.

I think it means that `import` will load all functions defined in a module, while `using` only imports the exported functions. Tried to clarify.

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**Author:** ![ScottPJones](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/scottpjones/32/146_2.png) [@ScottPJones](https://discourse.julialang.org/u/ScottPJones)\
**Post date:** [December 16, 2017, 9:23pm UTC](https://discourse.julialang.org/t/excellent-cheat-sheet/7792/23 "2017-12-16T21:23:42Z")

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> [@nickeubank](#):
>
> I think it means that import will load all functions defined in a module, while using only imports the exported functions. Tried to clarify.

No - see the section in the manual about the differences between `import` and `using`:  
[https://docs.julialang.org/en/latest/manual/faq/#What-is-the-difference-between-“using”-and-“import”?-1](https://docs.julialang.org/en/latest/manual/faq/#What-is-the-difference-between-%22using%22-and-%22import%22?-1)

Maybe you were thinking of `importall`, which I believe has been deprecated.

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<div class="post-metadata">

**Author:** ![nickeubank](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/nickeubank/32/3878_2.png) [@nickeubank](https://discourse.julialang.org/u/nickeubank)\
**Post date:** [December 16, 2017, 9:45pm UTC](https://discourse.julialang.org/t/excellent-cheat-sheet/7792/24 "2017-12-16T21:45:44Z")

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> [@ScottPJones](#):
>
> No - see the section in the manual about the differences between import and using:
> 
> [https://docs.julialang.org/en/latest/manual/faq/#What-is-the-difference-between-“using”-and-“import”?-1](https://docs.julialang.org/en/latest/manual/faq/#What-is-the-difference-between-%E2%80%9Cusing%E2%80%9D-and-%E2%80%9Cimport%E2%80%9D?-1)

ah, ok thanks! Will revert.

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**Author:** ![mortenpi](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/mortenpi/32/158_2.png) [@mortenpi](https://discourse.julialang.org/u/mortenpi)\
**Post date:** [December 19, 2017, 2:42am UTC](https://discourse.julialang.org/t/excellent-cheat-sheet/7792/25 "2017-12-19T02:42:39Z")

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The cheat sheet has been moved to the JuliaDocs org now, so the URL changed to [The Fast Track to Julia](https://juliadocs.github.io/Julia-Cheat-Sheet/)

It would probably be nice to update the link in the OP as well, in case someone stumbles onto this thread in the future.

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<div class="post-metadata">

**Author:** ![nickeubank](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/nickeubank/32/3878_2.png) [@nickeubank](https://discourse.julialang.org/u/nickeubank)\
**Post date:** [December 19, 2017, 3:52pm UTC](https://discourse.julialang.org/t/excellent-cheat-sheet/7792/26 "2017-12-19T15:52:08Z")

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done!

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**Author:** ![DrKrar](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/drkrar/32/3801_2.png) [@DrKrar](https://discourse.julialang.org/u/DrKrar)\
**Post date:** [August 24, 2018, 2:19pm UTC](https://discourse.julialang.org/t/excellent-cheat-sheet/7792/27 "2018-08-24T14:19:43Z")

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I think this cheat-sheet very useful and concise.  
[https://cheatsheets.quantecon.org/julia-cheatsheet.html](https://cheatsheets.quantecon.org/julia-cheatsheet.html)

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**Author:** ![joa-quim](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/joa-quim/32/227_2.png) [@joa-quim](https://discourse.julialang.org/u/joa-quim)\
**Post date:** [August 24, 2018, 3:04pm UTC](https://discourse.julialang.org/t/excellent-cheat-sheet/7792/28 "2018-08-24T15:04:17Z")

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But many things in it are no longer valid in 1.0

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**Author:** ![purplishrock](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/purplishrock/32/13451_2.png) [@purplishrock](https://discourse.julialang.org/u/purplishrock)\
**Post date:** [August 24, 2018, 5:25pm UTC](https://discourse.julialang.org/t/excellent-cheat-sheet/7792/29 "2018-08-24T17:25:52Z")

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ComplexN should be Complex{T}

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**Author:** ![chakravala](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/chakravala/32/6832_2.png) [@chakravala](https://discourse.julialang.org/u/chakravala)\
**Post date:** [August 24, 2018, 8:31pm UTC](https://discourse.julialang.org/t/excellent-cheat-sheet/7792/30 "2018-08-24T20:31:28Z")

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is there a PDF available somewhere?

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<div class="post-metadata">

**Author:** ![nickeubank](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/nickeubank/32/3878_2.png) [@nickeubank](https://discourse.julialang.org/u/nickeubank)\
**Post date:** [August 24, 2018, 8:46pm UTC](https://discourse.julialang.org/t/excellent-cheat-sheet/7792/31 "2018-08-24T20:46:30Z")

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I started an issue discussion of needed updates [here](https://github.com/JuliaDocs/Julia-Cheat-Sheet/issues/19)

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**Author:** ![Yifan\_Liu](https://avatars.discourse-cdn.com/v4/letter/y/4da419/32.png) [@Yifan\_Liu](https://discourse.julialang.org/u/Yifan_Liu)\
**Post date:** [August 26, 2018, 2:41pm UTC](https://discourse.julialang.org/t/excellent-cheat-sheet/7792/32 "2018-08-26T14:41:02Z")

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Can we have a collection of cheat sheets of Julia and the popular libraries like this one:

> **[Posit](https://posit.co/resources/cheatsheets/)**

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<div class="post-metadata">

**Author:** ![DrKrar](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/drkrar/32/3801_2.png) [@DrKrar](https://discourse.julialang.org/u/DrKrar)\
**Post date:** [August 26, 2018, 4:05pm UTC](https://discourse.julialang.org/t/excellent-cheat-sheet/7792/33 "2018-08-26T16:05:14Z")

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you are right but this the case for many non-offical docs. [joa-quim](https://discourse.julialang.org/u/joa-quim)

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<div class="post-metadata">

**Author:** ![nickeubank](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/nickeubank/32/3878_2.png) [@nickeubank](https://discourse.julialang.org/u/nickeubank)\
**Post date:** [September 30, 2018, 3:57am UTC](https://discourse.julialang.org/t/excellent-cheat-sheet/7792/34 "2018-09-30T03:57:43Z")

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[The Fast Track to Julia](https://juliadocs.github.io/Julia-Cheat-Sheet/) is updated for Julia 1.0 now!

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<div class="post-metadata">

**Author:** ![Yifan\_Liu](https://avatars.discourse-cdn.com/v4/letter/y/4da419/32.png) [@Yifan\_Liu](https://discourse.julialang.org/u/Yifan_Liu)\
**Post date:** [September 30, 2018, 4:12am UTC](https://discourse.julialang.org/t/excellent-cheat-sheet/7792/35 "2018-09-30T04:12:32Z")

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Do you have a offline pdf version of the cheat sheet?

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<div class="post-metadata">

**Author:** ![tlienart](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/tlienart/32/7640_2.png) [@tlienart](https://discourse.julialang.org/u/tlienart)\
**Post date:** [September 30, 2018, 4:52am UTC](https://discourse.julialang.org/t/excellent-cheat-sheet/7792/36 "2018-09-30T04:52:24Z")

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Printing from browser gave me a [decent, compact pdf](https://www.dropbox.com/s/yj99rhjy8cic2d1/fast-track-to-julia.pdf?dl=0) which may be what you’re looking for.

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<div class="post-metadata">

**Author:** ![chakravala](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/chakravala/32/6832_2.png) [@chakravala](https://discourse.julialang.org/u/chakravala)\
**Post date:** [October 2, 2018, 10:49pm UTC](https://discourse.julialang.org/t/excellent-cheat-sheet/7792/37 "2018-10-02T22:49:31Z")

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It would be nice if the PDF could be specifically created to fit on a single 2-sided paper.

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<div class="post-metadata">

**Author:** ![nickeubank](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/nickeubank/32/3878_2.png) [@nickeubank](https://discourse.julialang.org/u/nickeubank)\
**Post date:** [October 3, 2018, 12:47am UTC](https://discourse.julialang.org/t/excellent-cheat-sheet/7792/38 "2018-10-03T00:47:59Z")

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PRs welcome! 🙂

The cheatsheet is fully flexible in terms of format (it’s in markdown / html), so if you can’t fit everything on one sheet, you could just subset the blocks you think are most useful, build it, and print to PDF in any web browser!

[Previous page](https://discourse.julialang.org/t/excellent-cheat-sheet/7792.md?page=1)