# List of use´d or import'ed modules in a Julia session
**URL:** https://discourse.julialang.org/t/list-of-use-d-or-imported-modules-in-a-julia-session/94584
**Category:** General Usage
**Tags:** modules
**Created:** [February 13, 2023, 9:14pm UTC](https://discourse.julialang.org/t/list-of-use-d-or-imported-modules-in-a-julia-session/94584 "2023-02-13T21:14:25Z")
**Posts on this page:** 10
**Page:** 1
### Author:  [@mocalvao](https://discourse.julialang.org/u/mocalvao)
#### Post date: [February 13, 2023, 9:14pm UTC](https://discourse.julialang.org/t/list-of-use-d-or-imported-modules-in-a-julia-session/94584/1 "2023-02-13T21:14:25Z")
Hi there
I would like to understand a little bit more about the answer to the question implied on the title of this topic of mine, as per the following question from StackOverflow: [List of loaded/imported packages in Julia](https://stackoverflow.com/questions/25575406/list-of-loaded-imported-packages-in-julia). The answer by Przemislaw Szufel seems the best one for me:
`filter((x) -> typeof(eval(x)) <: Module && x ≠ :Main, names(Main,imported=true))`
but I do not understand clearly the need for the `eval` function inside the `typeof` function in the conditional to the filter function. Could someone explain it from first principles? I have looked up the help for `eval` to no avail…
---
### Author:  [@baggepinnen](https://discourse.julialang.org/u/baggepinnen)
#### Post date: [February 14, 2023, 5:12am UTC](https://discourse.julialang.org/t/list-of-use-d-or-imported-modules-in-a-julia-session/94584/2 "2023-02-14T05:12:51Z")
`names` returns a list of symbols, `eval(name)` “evaluates” the symbol into the object it represents in the current Julia session. `typeof(eval(x)) <: Module` checks whether or not that object is a module.
You also have access to the `Dict`
```julia
ulia> Base.loaded_modules
Dict{Base.PkgId, Module} with 194 entries:
OpenSSL_jll [458c3c95-2e84-50aa-8efc-19380b2a3a95] => OpenSSL_jll
Xorg_xcb_util_jll [2def613f-5ad1-5310-b15b-b15d46f528f5] => Xorg_xcb_util_jll
libass_jll [0ac62f75-1d6f-5e53-bd7c-93b484bb37c0] => libass_jll
Qt5Base_jll [ea2cea3b-5b76-57ae-a6ef-0a8af62496e1] => Qt5Base_jll
Xorg_xcb_util_image_jll [12413925-8142-5f55-bb0e-6d7ca50bb09b] => Xorg_xcb_util_image_jll
Libgcrypt_jll [d4300ac3-e22c-5743-9152-c294e39db1e4] => Libgcrypt_jll
SnoopPrecompile [66db9d55-30c0-4569-8b51-7e840670fc0c] => SnoopPrecompile
.
.
.
```
which is an explicit list of loaded modules. These will in general include modules that are not available in Main.
---
### Author:  [@GunnarFarneback](https://discourse.julialang.org/u/GunnarFarneback)
#### Post date: [February 14, 2023, 6:50am UTC](https://discourse.julialang.org/t/list-of-use-d-or-imported-modules-in-a-julia-session/94584/3 "2023-02-14T06:50:23Z")
In this case you can replace `eval(x)` with the conceptually much simpler `getfield(Main, x)`. So no, there’s no need for `eval` here.
---
### Author:  [@rafael.guerra](https://discourse.julialang.org/u/rafael.guerra)
#### Post date: [February 14, 2023, 9:03am UTC](https://discourse.julialang.org/t/list-of-use-d-or-imported-modules-in-a-julia-session/94584/4 "2023-02-14T09:03:47Z")
@baggepinnen, `showall(Base.loaded_modules)` returns 174 items, including crazy things like `FriBidi_jll`, while the @pszufe’s user function `loadedModules()` returns 16 explicitly loaded packages, as expected.
Any further insights on this difference?
---
### Author:  [@pszufe](https://discourse.julialang.org/u/pszufe)
#### Post date: [February 14, 2023, 9:54am UTC](https://discourse.julialang.org/t/list-of-use-d-or-imported-modules-in-a-julia-session/94584/5 "2023-02-14T09:54:58Z")
`Base.loaded_modules` includes all dependencies of imported packages.
---
### Author:  [@mocalvao](https://discourse.julialang.org/u/mocalvao)
#### Post date: [February 14, 2023, 10:20am UTC](https://discourse.julialang.org/t/list-of-use-d-or-imported-modules-in-a-julia-session/94584/6 "2023-02-14T10:20:57Z")
I still do not get the need for `eval`: I tried
```julia
x =names(Main, imported=true)
```
and then
```julia
eval(x)
```
and they both seem to have the exact same output, of type `Vector{Symbol}`. So why does the call
```julia
filter((x) -> typeof(x) <: Module && x ≠ :Main, names(Main,imported=true))
```
provide an empty Symbol, whereas the original one by @pszufe does what was wanted?
---
### Author:  [@rafael.guerra](https://discourse.julialang.org/u/rafael.guerra)
#### Post date: [February 14, 2023, 10:40am UTC](https://discourse.julialang.org/t/list-of-use-d-or-imported-modules-in-a-julia-session/94584/7 "2023-02-14T10:40:42Z")
The original filter code in the OP iterates over a vector of symbols and evals **each** of them. Each type is then a `Module`, not a `Symbol`.
---
### Author:  [@baggepinnen](https://discourse.julialang.org/u/baggepinnen)
#### Post date: [February 14, 2023, 10:44am UTC](https://discourse.julialang.org/t/list-of-use-d-or-imported-modules-in-a-julia-session/94584/8 "2023-02-14T10:44:31Z")
`Base.loaded_modules` appears to include all modules that are loaded, even if they are loaded indirectly (not explicitly by the user). This includes jll packages that contain pre-compiled and packaged binaries.
---
### Author:  [@mocalvao](https://discourse.julialang.org/u/mocalvao)
#### Post date: [February 14, 2023, 2:07pm UTC](https://discourse.julialang.org/t/list-of-use-d-or-imported-modules-in-a-julia-session/94584/9 "2023-02-14T14:07:26Z")
I noticed that, but why does eval(:Base) for instance returns Base (which happens to be of type Module, no longer Symbol)? I was not able to get this crystal clear from `eval`’s function help, though I do see, via the REPL, it is what it does. I guess I really do not get what `eval` does…
---
### Author:  [@rafael.guerra](https://discourse.julialang.org/u/rafael.guerra)
#### Post date: [February 14, 2023, 2:18pm UTC](https://discourse.julialang.org/t/list-of-use-d-or-imported-modules-in-a-julia-session/94584/10 "2023-02-14T14:18:33Z")
It evaluates the symbol in global scope, and it will return its object, or an error if undefined:
```julia
x = 2
:x + 2 # Error, cannot add Symbol and Int
eval(:x) + 2 # 4
Symbol(:x, 0) # :x0
eval(Symbol(:x,0)) # Error x0 not defined
```