# Dynamically constructing a using statement
**URL:** https://discourse.julialang.org/t/dynamically-constructing-a-using-statement/8585
**Category:** New to Julia
**Created:** [January 25, 2018, 2:17am UTC](https://discourse.julialang.org/t/dynamically-constructing-a-using-statement/8585 "2018-01-25T02:17:16Z")
**Posts on this page:** 7
**Page:** 1
### Author:  [@tk3369](https://discourse.julialang.org/u/tk3369)
#### Post date: [January 25, 2018, 2:17am UTC](https://discourse.julialang.org/t/dynamically-constructing-a-using-statement/8585/1 "2018-01-25T02:17:16Z")
I think it should be doable with `@eval` but I’m stuck at the moment… I have a set of packages in an array and I’d like to run a `using` statement on them. My first attempt of constructing a comma-delimited string doesn’t work…
```julia
julia> x = ["BenchmarkTools", "Plots"]
2-element Array{String,1}:
"BenchmarkTools"
"Plots"
julia> pkgs = join(x, ",")
"BenchmarkTools,Plots"
julia> @eval using $pkgs
ERROR: TypeError: import or using: expected Symbol, got String
Stacktrace:
[1] eval(::Module, ::Expr) at ./sysimg.jl:23
```
---
### Author:  [@bramtayl](https://discourse.julialang.org/u/bramtayl)
#### Post date: [January 25, 2018, 2:55am UTC](https://discourse.julialang.org/t/dynamically-constructing-a-using-statement/8585/2 "2018-01-25T02:55:23Z")
x = [:BenchmarkTools, :Plots]
e = Expr(:toplevel, map(x → Expr(:using, x), x)…)
eval(e)
---
### Author:  [@Tamas\_Papp](https://discourse.julialang.org/u/Tamas_Papp)
#### Post date: [January 25, 2018, 6:09am UTC](https://discourse.julialang.org/t/dynamically-constructing-a-using-statement/8585/3 "2018-01-25T06:09:48Z")
@bramtayl’s answer should be helpful, but can you give a bit more context? _Why_ are you trying to do this? Depending on the objective, perhaps there is a simpler way of achieving it.
---
### Author:  [@tk3369](https://discourse.julialang.org/u/tk3369)
#### Post date: [January 25, 2018, 6:23am UTC](https://discourse.julialang.org/t/dynamically-constructing-a-using-statement/8585/4 "2018-01-25T06:23:37Z")
I’m trying to force precompilation of all packages so that the package images are written then I can fix the Unix file permissions… I think I submitted another post some time ago regarding the file permission problem. So this is really a workaround.
---
### Author:  [@Tamas\_Papp](https://discourse.julialang.org/u/Tamas_Papp)
#### Post date: [January 25, 2018, 6:39am UTC](https://discourse.julialang.org/t/dynamically-constructing-a-using-statement/8585/5 "2018-01-25T06:39:10Z")
I see. You may be interested in these comments:
[https://github.com/JuliaLang/julia/issues/16409#issuecomment-228873060](https://github.com/JuliaLang/julia/issues/16409#issuecomment-228873060)
and
[https://github.com/JuliaLang/julia/issues/16409#issuecomment-242360802](https://github.com/JuliaLang/julia/issues/16409#issuecomment-242360802)
---
### Author:  [@kristoffer.carlsson](https://discourse.julialang.org/u/kristoffer.carlsson)
#### Post date: [January 25, 2018, 7:39am UTC](https://discourse.julialang.org/t/dynamically-constructing-a-using-statement/8585/6 "2018-01-25T07:39:51Z")
Use symbols instead of strings in `x` then just do
```julia
for pkg in x
@eval using $pkg
end
```
---
### Author:  [@Liso](https://discourse.julialang.org/u/Liso)
#### Post date: [January 26, 2018, 10:14pm UTC](https://discourse.julialang.org/t/dynamically-constructing-a-using-statement/8585/7 "2018-01-26T22:14:25Z")
I am still newbie but would try something like this:
```julia
for pkg in x
try
info("importing: $pkg")
@eval import $(Symbol(pkg))
# next line you probably want to change file permission
run(Cmd(["ls", "-la", joinpath(replace(Pkg.dir(), ".julia", ".julia/lib"), pkg*".ji")]))
catch e
println("$e")
end
end
```
import could probably avoid some name clash problems…
run(Cmd(…)) is not the best (replace is ugly hack too) and you’ll very probably find better way. 🙂