# How to test if package is installed

**URL:** <https://discourse.julialang.org/t/how-to-test-if-package-is-installed/3508>\
**Category:** General Usage\
**Tags:** question\
**Created:** [May 4, 2017, 6:18am UTC](https://discourse.julialang.org/t/how-to-test-if-package-is-installed/3508 "2017-05-04T06:18:47Z")\
**Posts on this page:** 20\
**Page:** 1

<div class="post-metadata">

**Author:** ![Tamas\_Papp](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/tamas_papp/32/25949_2.png) [@Tamas\_Papp](https://discourse.julialang.org/u/Tamas_Papp)\
**Post date:** [May 4, 2017, 6:18am UTC](https://discourse.julialang.org/t/how-to-test-if-package-is-installed/3508/1 "2017-05-04T06:18:47Z")

</div>

What’s the recommended API for testing if a package (_which may not be registed_) is installed? I have seen two versions floating around:

```julia
"somepackage" ∈ keys(Pkg.installed())

```

and

```julia
isdir(Pkg.dir("somepackage"))

```

The second one feels hackish. First I thought checking `Pkg.installed("somepackage")` but that can return an error for unregistered, uninstalled packages.

(This is for use in `.juliarc.jl`, when running different versions.)

---

<div class="post-metadata">

**Author:** ![fengyang.wang](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/fengyang.wang/32/104_2.png) [@fengyang.wang](https://discourse.julialang.org/u/fengyang.wang)\
**Post date:** [May 4, 2017, 6:42am UTC](https://discourse.julialang.org/t/how-to-test-if-package-is-installed/3508/2 "2017-05-04T06:42:26Z")

</div>

The second one is very similar to how Pkg itself does it, so I would not say it’s hackish (unless you believe the approach of `Pkg` itself to be hackish). If you want to match exactly how Pkg determines if a package is installed, use

```julia
isinstalled(pkg::AbstractString) =
    pkg != "METADATA" && pkg != "REQUIRE" && pkg[1] != '.' && Pkg.cd(isdir, pkg)

```

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<div class="post-metadata">

**Author:** ![tkelman](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/tkelman/32/692_2.png) [@tkelman](https://discourse.julialang.org/u/tkelman)\
**Post date:** [May 4, 2017, 8:45am UTC](https://discourse.julialang.org/t/how-to-test-if-package-is-installed/3508/3 "2017-05-04T08:45:47Z")

</div>

Pkg doesn’t have the most useful conception of what “installed” means at the moment. What are you trying to accomplish? Modules can be used from anywhere on LOAD\_PATH without Pkg knowing anything about them.

---

<div class="post-metadata">

**Author:** ![Tamas\_Papp](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/tamas_papp/32/25949_2.png) [@Tamas\_Papp](https://discourse.julialang.org/u/Tamas_Papp)\
**Post date:** [May 4, 2017, 9:08am UTC](https://discourse.julialang.org/t/how-to-test-if-package-is-installed/3508/4 "2017-05-04T09:08:07Z")

</div>

basically, something like this in `.juliarc`:

```julia
if (SomePackage is installed) && (VERSION >= v"0.6-")
   eval(quote
           import SomePackage
           SomePackage.dostuff(...)
        end)
end

```

ie using a package but not causing an error if it is not available.

---

<div class="post-metadata">

**Author:** ![kristoffer.carlsson](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/kristoffer.carlsson/32/22_2.png) [@kristoffer.carlsson](https://discourse.julialang.org/u/kristoffer.carlsson)\
**Post date:** [May 4, 2017, 9:42am UTC](https://discourse.julialang.org/t/how-to-test-if-package-is-installed/3508/5 "2017-05-04T09:42:23Z")

</div>

Can’t you just use a `try catch`?

---

<div class="post-metadata">

**Author:** ![BVPs](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/bvps/32/2190_2.png) [@BVPs](https://discourse.julialang.org/u/BVPs)\
**Post date:** [August 11, 2018, 6:02am UTC](https://discourse.julialang.org/t/how-to-test-if-package-is-installed/3508/6 "2018-08-11T06:02:06Z")

</div>

With Julia v0.7.0 and v1.0.0 releases, I want to revive this topic. The reason is that `Pkg.installed` does not exist anymore in these new releases. Moreover, executing, say, `Pkg.dir("OhMyREPL)` gives us the following warning on v0.7.0:

```julia
WARNING: Base.Pkg is deprecated, run `using Pkg` instead
  likely near /Users/xxx/.julia/config/startup.jl:1
┌ Warning: `Pkg.dir(pkgname, paths...)` is deprecated; instead, do `import OhMyREPL; joinpath(dirname(pathof(OhMyREPL)), "..", paths...)`.
└ @ Pkg.API /Users/osx/buildbot/slave/package_osx64/build/usr/share/julia/stdlib/v0.7/Pkg/src/API.jl:454

```

This system suggestion is not good since we want to do `isdir(Pkg.dir("OhMyREPL"))` and if `OhMyREPL.jl` is not installed, `import OhMyREPL` in the suggested solution generates error of course.  
So what would be a good solution for v0.7.0 and v1.0.0?  
Thanks!

---

<div class="post-metadata">

**Author:** ![tkoolen](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/tkoolen/32/1603_2.png) [@tkoolen](https://discourse.julialang.org/u/tkoolen)\
**Post date:** [August 11, 2018, 6:13am UTC](https://discourse.julialang.org/t/how-to-test-if-package-is-installed/3508/7 "2018-08-11T06:13:31Z")

</div>

So I’m inferring that your use case is that you want to check whether OhMyREPL is installed in your `startup.jl`, perhaps so that you can use it if it’s installed. I used to do this because I was changing `JULIA_PKGDIR` to get separate package environments, and OhMyREPL might not be installed in all of them. If you were doing the same thing, I can recommend simply installing OhMyREPL to your default package environment. If you do that, then running `julia --project` in some other directory will still result in OhMyREPL being on the `LOAD_PATH`, so it’s available regardless of your active project and you don’t need to check.

But maybe I’m wrong and you have a different use case.

---

<div class="post-metadata">

**Author:** ![BVPs](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/bvps/32/2190_2.png) [@BVPs](https://discourse.julialang.org/u/BVPs)\
**Post date:** [August 11, 2018, 8:14pm UTC](https://discourse.julialang.org/t/how-to-test-if-package-is-installed/3508/8 "2018-08-11T20:14:55Z")

</div>

Thanks a lot! However, if I put `using OhMyREPL` directly in my ~/.julia/config/startup.jl (v0.7/v1.0 replacement of ~/.juliarc.jl), then for normal Julia sessions, I don’t have any problem, but when I try to build Conda.jl, it somehow says that it cannot find OhMyREPL package and suggests that I should run `Pkg.add("OhMyREPL")` although I already added it.  
But then, I found an excellent solution posted by @Simon_Bolland:

> [@New Pkg: how to check if a package is installed?](https://discourse.julialang.org/t/new-pkg-how-to-check-if-a-package-is-installed/13141/3):
>
> I’d suggest using Pkg if in("OhMyREPL",keys(Pkg.installed())) @eval using OhMyREPL else @warn("OhMyREPL not installed") end

After putting this one in startup.jl, I haven’t got any error when building Conda.

---

<div class="post-metadata">

**Author:** ![kristoffer.carlsson](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/kristoffer.carlsson/32/22_2.png) [@kristoffer.carlsson](https://discourse.julialang.org/u/kristoffer.carlsson)\
**Post date:** [August 11, 2018, 8:26pm UTC](https://discourse.julialang.org/t/how-to-test-if-package-is-installed/3508/9 "2018-08-11T20:26:52Z")

</div>

> [@BVPs](#):
>
> but when I try to build Conda.jl, it somehow says that it cannot find OhMyREPL package and suggests that I should run `Pkg.add("OhMyREPL")`

Yeah, this is a known bug ([Building packages call `startup.jl` with every build · Issue #609 · JuliaLang/Pkg.jl · GitHub](https://github.com/JuliaLang/Pkg.jl/issues/609)) which will be adressed in Julia 1.0.1.

---

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**Author:** ![BVPs](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/bvps/32/2190_2.png) [@BVPs](https://discourse.julialang.org/u/BVPs)\
**Post date:** [August 11, 2018, 9:39pm UTC](https://discourse.julialang.org/t/how-to-test-if-package-is-installed/3508/10 "2018-08-11T21:39:36Z")

</div>

Thanks a lot! Good to know that it would be addressed in Julia 1.0.1!

---

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**Author:** ![JohnnyChen94](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/johnnychen94/32/29979_2.png) [@JohnnyChen94](https://discourse.julialang.org/u/JohnnyChen94)\
**Post date:** [August 27, 2018, 6:25pm UTC](https://discourse.julialang.org/t/how-to-test-if-package-is-installed/3508/11 "2018-08-27T18:25:24Z")

</div>

I don’t think `try catch` is a good idea, I mean, I’ll avoid using it if there is any other way to know if a package is intalled,

---

<div class="post-metadata">

**Author:** ![Tamas\_Papp](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/tamas_papp/32/25949_2.png) [@Tamas\_Papp](https://discourse.julialang.org/u/Tamas_Papp)\
**Post date:** [August 28, 2018, 7:35am UTC](https://discourse.julialang.org/t/how-to-test-if-package-is-installed/3508/12 "2018-08-28T07:35:37Z")

</div>

There is a recent issue

> <https://github.com/JuliaLang/Pkg.jl/issues/697>
>
> This is more a question than an issue.
> 
> In Pkg(2) I found it useful when givin…g talks to be able to have (in the first cell of a notebook) something like:
> 
> \>\>\>\>\>
> 
> \# Packages used in this talk
> 
> for p in ("BenchmarkTools","UnicodePlots","PyPlot")
> Pkg.installed(p) == nothing && Pkg.add(p)
> end
> 
> using "BenchmarkTools","UnicodePlots","PyPlot")
> 
> \>\>\>\>\>\>
> 
> I can not see how to do this using the Pkg3 API
> Is this available and I've missed it, planned for the future etc.?
> 
> Malcolm

but, with Pkg(3), I am no longer sure that this functionality should be used by other packages, except in exceptional circumstances.

If a package is needed, one can just specify it as a dependency in `Project.toml`, and let `Pkg` take care of the details. If functionality is conditional on a package being installed, we have

> **[GitHub - JuliaPackaging/Requires.jl: Lazy code loading for Julia](https://github.com/JuliaPackaging/Requires.jl)**
>
> Lazy code loading for Julia. Contribute to JuliaPackaging/Requires.jl development by creating an account on GitHub.

What I originally wanted to accomplish when I asked this question is solved by the latter.

---

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**Author:** ![Boris.Maillard](https://avatars.discourse-cdn.com/v4/letter/b/ecb155/32.png) [@Boris.Maillard](https://discourse.julialang.org/u/Boris.Maillard)\
**Post date:** [November 9, 2018, 3:42am UTC](https://discourse.julialang.org/t/how-to-test-if-package-is-installed/3508/13 "2018-11-09T03:42:48Z")

</div>

Hi, I am confused with Pkg.installed.  
I understand the function is no more existing in v1.0 but I get the list of installed packages when I ask Pkg.installed(). However, when I ask for a specific package like Pkg.installed(“Colors”), then I get an error.

```julia
**julia&gt;** Pkg.installed("Colors")
**ERROR:** MethodError: no method matching installed(::String)
Closest candidates are:
installed() at /Users/osx/buildbot/slave/package_osx64/build/usr/share/julia/stdlib/v1.0/Pkg/src/API.jl:278
Stacktrace:
 [1] top-level scope at **none:0**

```

What is your recommandation?  
Thanks for your help.

---

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**Author:** ![00vareladavid](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/00vareladavid/32/23521_2.png) [@00vareladavid](https://discourse.julialang.org/u/00vareladavid)\
**Post date:** [November 9, 2018, 4:02am UTC](https://discourse.julialang.org/t/how-to-test-if-package-is-installed/3508/14 "2018-11-09T04:02:30Z")

</div>

`Pkg.installed()` returns a `Dict`, it does not take arguments. So if you want to check for a specific package, use `haskey`. For example: `haskey(Pkg.installed(), "Colors")`

---

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**Author:** ![Boris.Maillard](https://avatars.discourse-cdn.com/v4/letter/b/ecb155/32.png) [@Boris.Maillard](https://discourse.julialang.org/u/Boris.Maillard)\
**Post date:** [November 9, 2018, 4:31am UTC](https://discourse.julialang.org/t/how-to-test-if-package-is-installed/3508/15 "2018-11-09T04:31:30Z")

</div>

> `Pkg.installed()` returns a `Dict`, it does not take arguments. So if you want to check for a specific package, use `haskey`. For example: `haskey(Pkg.installed(), "Colors")`

> * * *
> 
> [Visit Topic](https://discourse.julialang.org/t/how-to-test-if-package-is-installed/3508/14) or reply to this email to respond.

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**Author:** ![Zhong\_Pan](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/zhong_pan/32/19872_2.png) [@Zhong\_Pan](https://discourse.julialang.org/u/Zhong_Pan)\
**Post date:** [March 23, 2020, 3:07pm UTC](https://discourse.julialang.org/t/how-to-test-if-package-is-installed/3508/16 "2020-03-23T15:07:25Z")

</div>

So with Julia 1.4, I got deprecation warnings when I tried to use Pkg.installed() and Pkg.dir(). Question is, **what’s the standard way of checking if a package has been installed and instantiated in the current environment, programmatically, without using try… catch…?**

My use case: I made a package and posted it to the company’s internal Bitbucket server. Many scripts I made need to use that package. However, some of the users of those scripts do not have the knowledge or patience of opening up Bitbucket account with IT, installing Git, setting up the SSH public key, etc. Instead, they are more used to just getting the source in a local folder (which is source controlled by Perforce).

Therefore, in my script I will always check if the package has been installed; if yes, I’ll directly use it; if not, I will add the conventional Perforce folder to LOAD\_PATH, and use the package from there.

I don’t want to use “try… catch…” because I often use the visual debugger and have it break at any exception (even if caught), and I figure my users will do similar as they come from the .NET / Matlab world. However breaking at this package not found exception every time is not fun… 🙂

Thank you for the help!

---

<div class="post-metadata">

**Author:** ![Tamas\_Papp](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/tamas_papp/32/25949_2.png) [@Tamas\_Papp](https://discourse.julialang.org/u/Tamas_Papp)\
**Post date:** [March 23, 2020, 3:11pm UTC](https://discourse.julialang.org/t/how-to-test-if-package-is-installed/3508/17 "2020-03-23T15:11:19Z")

</div>

> [@Zhong\_Pan](#):
>
> **what’s the standard way of checking if a package has been installed and instantiated in the current environment, programmatically, without using try… catch…?**

Just instantiate the project.

[https://julialang.github.io/Pkg.jl/dev/environments/#Using-someone-else’s-project-1](https://julialang.github.io/Pkg.jl/dev/environments/#Using-someone-else's-project-1)

---

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**Author:** ![Zhong\_Pan](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/zhong_pan/32/19872_2.png) [@Zhong\_Pan](https://discourse.julialang.org/u/Zhong_Pan)\
**Post date:** [March 23, 2020, 3:18pm UTC](https://discourse.julialang.org/t/how-to-test-if-package-is-installed/3508/18 "2020-03-23T15:18:18Z")

</div>

Hi Tamas, thanks for quick reply.

As I mentioned in the use case, some users don’t have Bitbucket account and SSH access set up, so they cannot instantiate the package on the Bitbucket server.

In addition, even if they can, when they are traveling, they won’t be able to update any Julia packages without logging into the company VPN, as Julia package manager will stop when it cannot access the Bitbucket server which is behind the company’s firewall. Therefore some consider it annoying to even have any Bitbucket package installed. Instead they prefer to just push the source controlled folder to LOAD\_PATH and use it there. I personally prefer instantiating the proper environment, but for my users coming from .NET / Matlab / Python 2 (which means almost everybody :)), I don’t want to force them, because they will just refuse to use Julia and stay with Matlab / Python.

Besides, I think checking if a package is installed sounds like a very reasonable feature for a package manager to have.

Thanks!

---

<div class="post-metadata">

**Author:** ![Tamas\_Papp](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/tamas_papp/32/25949_2.png) [@Tamas\_Papp](https://discourse.julialang.org/u/Tamas_Papp)\
**Post date:** [March 23, 2020, 3:30pm UTC](https://discourse.julialang.org/t/how-to-test-if-package-is-installed/3508/19 "2020-03-23T15:30:24Z")

</div>

> [@Zhong\_Pan](#):
>
> Besides, I think checking if a package is installed sounds like a very reasonable feature for a package manager to have.

It is supported interactively, but the intended use is _declarative_: a project declares what it needs, and then the package manager takes care of it.

> [@Zhong\_Pan](#):
>
> they won’t be able to update any Julia packages without logging into the company VPN, as Julia package manager will stop when it cannot access the Bitbucket server which is behind the company’s firewall

I think there are two things being conflated here: making a consistent environment available, and updating packages. As for the second, I am not sure how you are planning to do it with some access to the git repository. But for the first, you can deliver a project with relative paths in the manifest, and just activate it. Or deliver a binary, see

> **[GitHub - JuliaLang/PackageCompiler.jl: Compile your Julia Package](https://github.com/JuliaLang/PackageCompiler.jl)**
>
> Compile your Julia Package. Contribute to JuliaLang/PackageCompiler.jl development by creating an account on GitHub.

---

<div class="post-metadata">

**Author:** ![Zhong\_Pan](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/zhong_pan/32/19872_2.png) [@Zhong\_Pan](https://discourse.julialang.org/u/Zhong_Pan)\
**Post date:** [March 23, 2020, 3:42pm UTC](https://discourse.julialang.org/t/how-to-test-if-package-is-installed/3508/20 "2020-03-23T15:42:07Z")

</div>

Thanks, I will try “deliver a project with relative paths in the manifest”.

Regarding the access to the git, my script only depends on one package I made that is on company’s Bitbucket server behind corporate firewalls; all other packages are open source packages on Github. (I guess this would be the most common use case for Julia users from a company.)

Therefore I am just trying to programmatically support both ways of package access: if the user has Bitbucket SSH access, use it; otherwise, use from a local directory. I guess this is not “a consistent” way since sometimes the package could be from LOAD\_PATH instead of the environment; but I still think this is a very practical use case for those pushing Julia to Matlab and Python 2 users in a company. (Actually most do not even want to move to Python 3 due to the changes invovled, which I thought is a chance for pushing Julia. 🙂 But virtual environment is also hard for them to pick up.)

I guess I got the point of having package manager manage the environment completely. For these special cases I’ll try to figure something out myself. Thanks!

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