Created R Package, Unable to Display Photo - r

Update
Issue resolved
Update, still not working
Tried the following in R file
(1) deleted both library(...) packages
(2) Added #import jpeg before ShowPalettePhoto() and #import tidyverse before RanglaPunjab() so roxygen automatically adds to NAMESPACE.
After running devtools::document(), ran devtools::use_package("jpeg") and devtools::use_package("tidyverse") to automatically add to DESCRIPTION.
Unfortunately, even in testing, I cannot get JPEG photo.
Here is GitHub repository, https://github.com/ArtieLadie/RanglaPunjab
I created R package according to this tutorial
It worked and I was able to execute all commands, including a function to display photo in another directory.
I uploaded to my GitHub account. Anyone can install package in R environment with install_github("ArtieLadie/RanglaPunjab")
I am able to run functions by adding RanglaPunjab:: in front of it, i.e.
RanglaPunjab::PaintPalette("Jutti")
?RanglaPunjab::MergePalette
However, when I try to run ?RanglaPunjab::ShowPalettePhoto("Teej") I get
Error in readJPEG(x, native = TRUE) : could not find function "readJPEG"
Before creating the package I added function to set working directory to file location, but it was creating errors when I ran install("RanglaPunjab"), i.e. "Cannot execute"
Here are the exact commands I had, which I had to delete from code
library(rstudioapi)
current_path <- getActiveDocumentContext()$path
setwd(dirname(current_path ))
Please help

Your dependencies are not handled correctly. Here you explicitly load packages with library(...). That is not how one does that in an R package. You should add your dependencies to the Imports: section of the DESCRIPTION file and use the package::function() syntax when calling the function. c.f. http://r-pkgs.had.co.nz/description.html#dependencies.
In addition, if you want the images to be installed with your package, you should place them for example in inst/pics. You can then get the path to these files with
system.file("pics", <file-name>, package = "RanglaPunjab")

Related

Creating R package using code from script file

I’ve written some R functions and dropped them into a script file using RStudio. These are bits of code that I use over and over, so I’m wondering how I might most easily create an R package out of them (for my own private use).
I’ve read various “how to” guides online but they’re quite complicated. Can anyone suggest an “idiot’s guide” to doing this please?
I've been involved in creating R packages recently, so I can help you with that. Before proceeding to the steps to be followed, there are some pre-requisites, which include:
RStudio
devtools package (for most of the functions involved in creation of a package)
roxygen2 package (for roxygen documentation)
In case you don't have the aforementioned packages, you can install them with these commands respectively:
install.packages("devtools")
install.packages("roxygen2")
Steps:
(1) Import devtools in RStudio by using library(devtools).
(devtools is a core package that makes creating R packages easier with its tools)
(2) Create your package by using:
create_package("~/directory/package_name") for a custom directory.
or
create_package("package_name") if you want your package to be created in current workspace directory.
(3) Soon after you execute this function, it will open a new RStudio session. You will observe that in the old session some lines will be auto-generated which basically tells R to create a new package with required components in the specified directory.
After this, we are done with this old instance of RStudio. We will continue our work on the new RStudio session window.
By far the package creation part is already over (yes, that simple) however, a package isn't directly functionable just by its creation plus the fact that you need to include a function in it requires some additional aspects of a package such as its documentation (where the function's title, parameters, return types, examples etc as mentioned using #param, #return etc - you would be familiar if you see roxygen documentation like in some github repositories) and R CMD checks to get it working.
I'll get to that in the subsequent steps, but just in case you want to verify that your package is created, you can look at:
The top right corner of the new RStudio session, where you can see the package name that you created.
The console, where you will see that R created a new directory/folder in the path that we specified in create_package() function.
The files panel of RStudio session, where you'll notice a bunch of new files and directories within your directory.
(4) As you mentioned in your words, you drop your functions in a script file - hence you will need to create the script first, which can be done using:
use_r("function_name")
A new R script will pop up in your working session, ready to be used.
Now go ahead and write your function(s) in it.
(5) After your done, you need to load the function(s) you have written for your package. This is accomplished by using the devtools::load_all() function.
When you execute load_all() in the console, you'll get to know that the functions have been loaded into your package when you'll see Loading package_name displayed in console.
You can try calling your functions after that in the console to verify that they work as a part of the package.
(6) Now that your function has been written and loaded into your package, it is time to move onto checks. It is a good practice to check the whole package as we make changes to our package. The function devtools::check() offers an easy way to do this.
Try executing check() in the console, it will go through a number of procedures checking your package for warnings/errors and give details for the same as messages on the screen (pertaining to what are the errors/warnings/notes). The R CMD check results at the end will contain the vital logs for you to see what are the errors and warnings you got along with their frequency.
If the functions in your package are written well, (with additional package dependencies taken care of) it will give you two warnings upon execution of check:
The first warning will be regarding the license that your package uses, which is not specified for a new pacakge.
The second should be the one for documentation, warning us that our code is not documented.
To resolve the first issue which is the license, use the use_mit_license("license_holder_name") command (or any other license which suits your package - but then for private use as you mentioned, it doesn't really matter what you specify if only your going to use it or not its to be distributed) with your name as in place of license_holder_name or anything which suits a license name.
This will add the license field in the .DESCRIPTION file (in your files panel) plus create additional files adding the license information.
Also you'll need to edit the .DESCRIPTION file, which have self-explanatory fields to fill-in or edit. Here is an example of how you can have it:
Package: Your_package_name
Title: Give a brief title
Version: 1.0.0.0
Authors#R:
person(given = "Your_first_name",
family = "Your_surname/family_name",
role = c("package_creator", "author"),
email = "youremailaddress#gmail.com",
comment = c(ORCID = "YOUR-ORCID-ID"))
Description: Give a brief description considering your package functionality.
License: will be updated with whatever license you provide, the above step will take care of this line.
Encoding: UTF-8
LazyData: true
To resolve the documentation warning, you'll need to document your function using roxygen documentation. An example:
#' #param a parameter one
#' #param b parameter two
#' #return sum of a and b
#' #export
#'
#' #examples
#' yourfunction(1,2)
yourfunction <- function(a,b)
{
sum <- a+b
return(sum)
}
Follow the roxygen syntax and add attributes as you desire, some may be optional such as #title for specifying title, while others such as #import are required (must) if your importing from other packages other than base R.
After your done documenting your function(s) using the Roxygen skeleton, we can tell our package that we have documented our functions by running devtools::document(). After you execute the document() command, perform check() again to see if you get any warnings. If you don't, then that means you're good to go. (you won't if you follow the steps)
Lastly, you'll need to install the package, for it to be accessible by R. Simply use the install() command (yes the same one you used at the beginning, except you don't need to specify the package here like install("package") since you are currently working in an instance where the package is loaded and is ready to be deployed/installed) and you'll see after a few lines of installation a statement like "Done (package_name)", which indicates the installation of our package is complete.
Now you can try your function by first importing your package using library("package_name") and then calling your desired function from the package. Thats it, congrats you did it!
I've tried to include the procedure in a lucid way (the way I create my R packages), but if you have any doubts feel free to ask.

How to load self-written package documentation with '?my_package_name'?

I made a package in R called "my_package_name". When I run ?my_package_name or ??_my_package_name, no results are found. I want a help file to be loaded in the same way that ?ggplot2 loads a package help file.
I can run ?my_function_name to obtain the help files for my functions. However, this does not work with my package name, even though the description file is complete. I found that help(package = my_package_name) loads a page that contains the description file and help pages, but I would like load a page with ?my_package_name.
I would say that the easiest way is probably to run the following from the usethis package. It will create the file needed to have your package documentation
usethis::use_package_doc()
I suggest reading the documentation of the function to understand what's going on under the hood.

C file does not work in my own R package?

I built my own package in R and created all my functions. Everything worked very well. Then, I want to include a .C files into my package.
I follow the structure in this link compiled code. Once I done that, my package stop working and cannot use it anymore.
I tried to fix it more than one time but nothing is happen. Then, I built another package and load my functions inside it (I was save a copy of my files).
Now I would like to start again but do not want to lose my function again. Any ideas?
Try to write your files first and make sure that they are work! Then build you package following the structures here.
Follow the structures step by step and you will be fine. Your package will set src file for you and all your other files.

How to call R script from another R script, both in same package?

I'm building a package that uses two main functions. One of the functions model.R requires a special type of simulation sim.R and a way to set up the results in a table table.R
In a sharable package, how do I call both the sim.R and table.R files from within model.R? I've tried source("sim.R") and source("R/sim.R") but that call doesn't work from within the package. Any ideas?
Should I just copy and paste the codes from sim.R and table.R into the model.R script instead?
Edit:
I have all the scripts in the R directory, the DESCRIPTION and NAMESPACE files are all set. I just have multiple scripts in the R directory. ~R/ has premodel.R model.R sim.R and table.R. I need the model.R script to use both sim.R and table.R functions... located in the same directory in the package (e.g. ~R/).
To elaborate on joran's point, when you build a package you don't need to source functions.
For example, imagine I want to make a package named TEST. I will begin by generating a directory (i.e. folder) named TEST. Within TEST I will create another folder name R, in that folder I will include all R script(s) containing the different functions in the package.
At a minimum you need to also include a DESCRIPTION and NAMESPACE file. A man (for help files) and tests (for unit tests) are also nice to include.
Making a package is pretty easy. Here is a blog with a straightforward introduction: http://hilaryparker.com/2014/04/29/writing-an-r-package-from-scratch/
As others have pointed out you don't have to source R files in a package. The package loading mechanism will take care of losing the namespace and making all exported functions available. So usually you don't have to worry about any of this.
There are exceptions however. If you have multiple files with R code situations can arise where the order in which these files are processed matters. Often it doesn't matter or the default order used by R happens to be fine. If you find that there are some dependencies within your package that aren't resolved properly you may be faced with a situation where a custom processing order for the R files is required. The DESCRIPTION file offers the optional Collate field for this purpose. Simply list all your R files in the order they should be processed to satisfy the dependencies.
If all your files are in R directory, any function will be in memory after you do a package build or Load_All.
You may have issues if you have code in files that is not in a function tho.
R loads files in alphabetical order.
Usually, this is not a problem, because functions are evaluated when they are called for execution, not at loading time (id. a function can refer another function not yet defined, even in the same file).
But, if you have code outside a function in model.R, this code will be executed immediately at time of file loading, and your package build will fail usually with a
ERROR: lazy loading failed for package 'yourPackageName'
If this is the case, wrap the sparse code of model.R into a function so you can call it later, when the package has fully loaded, external library too.
If this piece of code is there for initialize some value, consider to use_data() to have R take care of load data into the environment for you.
If this piece of code is just interactive code written to test and implement the package itself, you should consider to put it elsewhere or wrap it to a function anyway.
if you really need that code to be executed at loading time or really have dependency to solve, then you must add the collate line into DESCRIPTION file, as already stated by Peter Humburg, to force R to load files order.
Roxygen2 can help you, put before your code
#' #include sim.R table.R
call roxygenize(), and collate line will be generate for you into the DESCRIPTION file.
But even doing that, external library you may depend are not yet loaded by the package, leading to failure again at build time.
In conclusion, you'd better don't leave code outside functions in a .R file if it's located inside a package.
Since you're building a package, the reason why you're having trouble accessing the other functions in your /R directory is because you need to first:
library(devtools)
document()
from within the working directory of your package. Now each function in your package should be accessible to any other function. Then, to finish up, do:
build()
install()
although it should be noted that a simple document() call will already be sufficient to solve your problem.
Make your functions global by defining them with <<- instead of <- and they will become available to any other script running in that environment.

How do I load a package without installing it in R?

I have built an R package but I do not want my users to have to install it before using it.
Is there a way to load a package without having to install it?
For example, if I have a package mypackage.tar.gz, is there something like
library("mypackage.tar.gz")
?
I'll join in "the chorus" of suggesting you should really install the package.
That having been said, you can take a look at Hadley's devtools package, which will let you load packages into the workspace without dumping in your global workspace.
The package will have to be untar'd/unzipped and follow the standard R package structure.
In order for this to work, though, your users would have to have the devtools package installed, so ... I'm not sure that this is any type of win for you.
If you only need the code to be loaded without it being installed, take the raw R script and source it:
source(myScript.R)
If you have different functions, you can create an R script that just loads all the necessary source files. What I sometimes do when developing, is name all my functions F_some_function.R and my classes Class_some_function.R. This allows me to source a main file containing following code :
funcdir <- "C:/Some/Path"
files <- dir(funcdir)
srcfiles <- c(grep("^Class_",dir(funcdir),value=T),
grep("^F_",dir(funcdir),value=T)
)
for( i in paste(funcdir,srcfiles,sep="/")) source(i)
If you present them with the tarred file, they can untar themselves using untar() before sourcing the main file.
But honestly, please use a package. You load everything in the global environment (or in a specified environment if you use local=T), but you lose all functionality of a package. Installing a package is no hassle, and removing neither.
If it's a matter of writing rights on the C drive (which is the only possible reason not to use a package that I met in my carreer), one can easily set another library location. R 2.12 actually does this by itself on Windows. See ?.libPaths()

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