Load packages automatically without `using` in Julia? - julia

When looking at files like this: https://github.com/simon-lc/Silico.jl/blob/main/examples/demo/peg_in_hole_planning.jl
The author does not call "using Silico" or "using Mehrotra" anywhere, yet calls it many times throughout the file. As someone coming from Python, I don't understand this. How does Julia know where to look for Silico without a statement like "using Silico"?

For this, you can customize the configuration file of Julia.
For example, in Windows OS, you can go to the following path:
C://Users//.julia/config/startup.jl
Open the file and write the importing command(s) you want. E.g., using Term or using OhMyREPL and using Statistics: mean, std (then those functions will be available by default). Then every time you run the Julia, those packages will be imported automatically.
*Note that if this file doesn't exist in the path, you can create a file with the same name.
You can also compile the preferred packages into the Julia system image, and the Julia REPL will start a bit quicker since it does not have to parse and compile the package when loaded. The way to do this is by using PackageCompiler.jl. [1]

Related

R testthat: use external package only in test file - not in DESCRIPTION

I'm trying to run a testthat script using GitHub Actions.
I would like to test a functionality of my function that allows it to be combined with (many) external packages. Now I want to test these external packages for the R CMD Check but I don't want to load the external packages generally (i.e. putting them into the Description) - after all, most people will not use these external packages.
Any ideas how to just include an external package in the testing files but not in the DESCRIPTION?
Thanks!
I think you describe a very standard use of Suggests.
I see two related but separable issues:
You want to test something using CI, in this case GHA. That is fine. Because you control the execution of the code, you could move your code from the test runner to, say, inst/examples and call it explicitly. That way the standard check of 'is the package using undeclared code' passes as inst/examples is not checked
You want to not force other people to have to load these packages. That is fine too, and we have Suggests: for this! Read Section 1.1 of Writing R Extensions about all the detailed semantics. If your package invokes other packages via tests, the every R CMD check touches this (and the external packages) so they must be declared. But you already know that only "some" people will want to use this "some of the time": that is precisely what Suggests: does, and you bracket the use with if (requireNamespace(pkgHere, quietly=TRUE)).
You can go either way, or even combine both. But you cannot call packages from tests and not declare them.

Best way to reference files outside directory in R

So I use a lot of custom built functions in R which I save in the documents folder in my pc. I would like to bring these functions into my R environment (I usually use source()). At the moment I use the entire file path, i.e. C:\Users\usename\documents\R functions\my_function.r and then create a quick access shortcut link in my project directory to these functions (for easy reference in case its needed). However I was wondering if there is a better way to reference these files. By better I basically mean shorter, or a way to source the files through the quick access shortcut. An alternative to this would be to create a secondary directory so I could just type source("&/my_function.r") (the "&" means secondary directory). This is just a minor inconvenience I think would make life easier if resolved. What do yo think? is this unnecessary complication? Is there anyone in a similar situation as me that has any tips for easily sourcing functions?
Thanks a lot!
If these are functions you often use, you could wrap them in a minimalistic package. Then your call would just be library("myhelpers") and you have all of them available.
Creating this package is quite easy. Assuming you use RStudio, you just:
Create a package: File -> New Project -> New Directory -> R Package
Give it the name you want e.g. "myhelpers"
Specify the folder it should be in
Then RStudio directly creates the package structure for you.
Now you have the package structure in your folder. It will look like this:
- DESCRIPTION
- man
- NAMESPACE
- R
- myhelpers.Rproj
You just have to put your .R files with the functions in the R folder. It does not matter, if the functions are in one file or in multiple files.
Then in R Studio go to the Tab "Build" and click "Install and and Restart". That's it!
Now in your other projects or R files you can just type and use all the functions you put in the R folder:
library("myhelpers")
var <- myfunction1(x)
If you later on want to edit your package functions or add new ones, you can just go to the package folder and click on myhelpers.Rproj and RStudio will open your package project for you. After your changes just click again Build -> Install and and Restart to update the package.
Here is also a short explanation with pictures. This is all you need to use your functions for yourself. The nice thing is, from there you can also go further if needed. E.g. add documentation to your functions. (then you could also have a help() page to your function).

Are there any good resources/best-practices to "industrialize" code in R for a data science project?

I need to "industrialize" an R code for a data science project, because the project will be rerun several times in the future with fresh data. The new code should be really easy to follow even for people who have not worked on the project before and they should be able to redo the whole workflow quite quickly. Therefore I am looking for tips, suggestions, resources and best-practices on how to achieve this objective.
Thank you for your help in advance!
You can make an R package out of your project, because it has everything you need for a standalone project that you want to share with others :
Easy to share, download and install
R has a very efficient documentation system for your functions and objects when you work within R Studio. Combined with roxygen2, it enables you to document precisely every function, and makes the code clearer since you can avoid commenting with inline comments (but please do so anyway if needed)
You can specify quite easily which dependancies your package will need, so that every one knows what to install for your project to work. You can also use packrat if you want to mimic python's virtualenv
R also provide a long format documentation system, which are called vignettes and are similar to a printed notebook : you can display code, text, code results, etc. This is were you will write guidelines and methods on how to use the functions, provide detailed instructions for a certain method, etc. Once the package is installed they are automatically included and available for all users.
The only downside is the following : since R is a functional programming language, a package consists of mainly functions, and some other relevant objects (data, for instance), but not really scripts.
More details about the last point if your project consists in a script that calls a set of functions to do something, it cannot directly appear within the package. Two options here : a) you make a dispatcher function that runs a set of functions to do the job, so that users just have to call one function to run the whole method (not really good for maintenance) ; b) you make the whole script appear in a vignette (see above). With this method, people just have to write a single R file (which can be copy-pasted from the vignette), which may look like this :
library(mydatascienceproject)
library(...)
...
dothis()
dothat()
finishwork()
That enables you to execute the whole work from a terminal or a distant machine with Rscript, with the following (using argparse to add arguments)
Rscript myautomatedtask.R --arg1 anargument --arg2 anotherargument
And finally if you write a bash file calling Rscript, you can automate everything !
Feel free to read Hadley Wickham's book about R packages, it is super clear, full of best practices and of great help in writing your packages.
One can get lost in the multiple files in the project's folder, so it should be structured properly: link
Naming conventions that I use: first, second.
Set up the random seed, so the outputs should be reproducible.
Documentation is important: you can use the Roxygen skeleton in rstudio (default ctrl+alt+shift+r).
I usually separate the code into smaller, logically cohesive scripts, and use a main.R script, that uses the others.
If you use a special set of libraries, you can consider using packrat. Once you set it up, you can manage the installed project-specific libraries.

Import a module and use it in julialang

Since in http://julia.readthedocs.org/en/latest/manual/modules/ there's no much info about modules, I would like to ask the following.
I want to try two modules via ijulia. Both modules are in my working directory as
name-of-files.jul. I will call them generically module_1.jul and module_2.jul.
module_1.jul uses module_2.jul and I load it with
using module_2
On ijulia session, if I try
using module_1
gives an error. I also tried
include("module_1.jul")
This last sentence, when executed, rises an error because the module_1.jul cannot find
variable "x" that I know is contained in module_1.jul (in this case I "loaded" the module
using include("module2.jul") inside module_1.jul
Julias module system assumes some things that aren't necessarily obvious from the documenation at first.
Julia files should end with .jl extensions.
Julia looks for module files in directories defined in the LOAD_PATH variable.
Julia looks for files in those directories in the form ModuleName/src/file.jl
If using module_1 fails then I'm guessing it's because it's source files fail one of the above criteria.
Some time has passed since this question. Recently, Noah_S wrote the solution in the comments of the previous answer; this means that it is a recurrent doubt for people starting to learn the language. For their sake, I will re-write it here Noah_S' answer along with my most novel solution.
I am a mess with the julia versions and which commands work with the specific ones, so for older julia versions we have to look for the \path and then include in the julia module
push!(LOAD_PATH, "/path")
In newer versions this can be improved. Forget about looking by hand the path and just do
path = readstring(`pwd`)
push!(LOAD_PATH, chomp(path))
I hope this can be useful to many julians newcomers.

R2PPT crashes R; are there alternatives to R2PPT?

I am attempting to automate the insertion of JPEG images into Powerpoint. I have a macro done for that already, except using R would be infinitely better for my purposes.
The package R2PPT should do this, I understand. However, I cannot use it. For example, when I try to use PPT.Open, I understand I can do it two different ways by calling method = "rcom" or method = "RDCOMClient". Using the latter, R will always crash, sending an error report to windows. Using the former, it tells me I need to install statconnDCOM , before giving the error:
Error in PPT.Open(x) : attempt to apply non-function.
I cannot install statconnDCOM freely, as I wouldn't call this work non-commercial. So if there isn't a way to get around this issue, are there at least some free alternatives to R2PPT so that I can save several hours of manual work with a simple R code? If there is a way for me to use R2PPT, that would be ideal.
Thanks!
Edit:
I'm using R version 2.15 and downloaded the most recent version of R2PPT. Powerpoint is 2007.
Do you have administrative privileges on this machine?
There is an issue with package RDCOMClient. It needs permissions to write file rdcom.err in the root of drive C:. If you don't have privileges to write to c:, there is a rather cumbersome workaround:
Close R
Create "c:\temp" folder if it doesn't exist.
Locate on your hard drive file rdcomclient.dll. It usually placed in \R\library\RDCOMClient\libs\i386\ and in \R\library\RDCOMClient\libs\x64\ (you need to patch file which corresponds your Windows version - 32 bit or 64 bit). It's recommended to make backup copy of this files before patching.
Open rdcomclient.dll in text editor (Notepad++, for example -http://notepad-plus-plus.org/)
Find in file string c:\rdcom.err - it occurs only once.
Go into overwrite mode (usually by pressing "Ins" key). It is very important that new path will have the same number of characters as original one. Type C:\temp\e.rr instead of c:\rdcom.err
Save the file.
Now all should work fine.
Arguably not an answer, but have you looked at using Sweave/knitr to render your presentations in LaTeX using something like Beamer? (As discussed on slide 17 here.)
Wouldn't help any with getting JPGs into a PowerPoint, but would certainly make putting R-output (numerical or graphical) into a presentation much easier!
Edit: if you want to use knitr (which I recommend), here's another reference.

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