Writing r function documentation software

Using and creating online documentation for classes and methods. For more detailed documentation of code a popular style is the one used for the numpy project, often called numpy style docstrings. Make the script in r suppose you want to present fractional numbers. The functions summary and anova are used to obtain and print a summary and analysis of variance table of the results. Technical writing is an art that doesnt come naturally. You can write a quick, oneline function or long elaborate functions. R objects are documented in files written in r documentation rd format.

One of the core requirements for r packages is that all exported functions, objects, and datasets. It can be also used to generate word document from a. It is also used as an agreement or as the foundation for agreement on what the software will do. To create a function in r, you will make and transform an r script. By default, power bi desktop doesnt include, deploy, or install the r engine. Those are calls see call in r, and an r expression vector is a list of calls, symbols etc, for example as returned by parse. This post will introduce you to the notion of function from the r programmer point of view and will illustrate the range of action that. You can create a new rd file for an existing function, dataset, or other object in. This is a guide to extending r, describing the process of creating r addon packages, writing r documentation, r s system and foreign language interfaces, and the r api.

Suppose you want to present fractional numbers as percentages, nicely rounded to one decimal digit. The lgl format is also a simple text file, this is the format expected by the large graph layout layout generator software. The tutorial highlights what r functions are, user defined functions in r, scoping in r, making your own functions in r, and much more. Writing documentation will start you down the road to being a better technical writer, which is a useful skill to have as a programmer.

This is a guide to extending r, describing the process of creating r addon packages, writing r documentation, rs system and foreign language interfaces, and the r api. Reporters package, by david gohel, provides easy to use functions to write and format word documents. To use the testthat package you will put a file called testareapackagename. A common way to put documentation in software is to add comments like this. The goal of roxygen2 is to make documenting your code as easy as possible. Write all of your functions rst in r or rstudio and make sure they work properly before you start compiling your package. Techniques to access this documentation and to create it in r help files are described here. Software documentation is written text or illustration that accompanies computer software or is embedded in the source code.

Rd files are saved in the man directory of an r package. Home how to write a good documentation library guides at. The documentation either explains how the software operates or how to use it, and may mean different things to people in different roles. Sep 30, 2019 good software documentation is specific, concise, and relevant, providing all the information important to the person using the software. Background in previous posts, i covered a number of useful functions and packages for writing reusable code. Help text appears in the command window when you use the help function create help text by inserting comments at the beginning of your program. Jun 08, 2014 when you have multiple arguments in a function that you call, r will just evaluate them in order of how youve written the function the first argument will correspond to x. In r, a function is an object so the r interpreter is able to pass control to the function, along with arguments that may be necessary for the function to accomplish the actions. We have made a number of small changes to reflect differences between the r and s programs, and expanded some of the material. R in the insttests directory, where area is the name of the broad class of functions you are testing. Translations of manuals into other languages than english are available from the contributed documentation section only a few translations are available the latex or texinfo sources of the latest version of these documents are contained in every r source distribution in the subdirectory docmanual of the extracted archive. In fact, many of the functions in r are actually functions of functions. Technical writing for software documentation writers. In a previous post, you covered part of the r language control flow, the cycles or loop structures.

With the default source null, the function will automatically suggest an appropriate source entry for cran and github packages, but for other r packages it is left to the user to add information about where the software can be accessed. Help text appears in the command window when you use the help function. The documentation sits just above the function code, so it is there front and center. I then enrolled in writingbased physics and math classes, where i. Apr 16, 2016 in my view from a software developers perspective, there are four levels of documentation. These are often aesthetics, used to set an aesthetic to a fixed value, like colour red or size 3. The procedure for writing any other functions is similar, involving three key steps. Where can i find a list of all the possible arguments one could use in the ellipsis argument for each geomstat function. R has a fantastic package roxygen2 that makes documenting functions quite easy.

You just use the same language you always use in r, in the same file as the rest of your code if you like. This is an introduction to r gnu s, a language and environment for statistical computing and graphics. The rst place r looks is in the workspace also known as the global environment. This introduction to r is derived from an original set of notes describing the s and splus environments written in 19902 by bill venables and david m. Writing functions using r in the following handout words and symbols in bold are r functions and words and symbols in italics are entries supplied by the user. Formal documentation for r functions is written in separate. Write the damn documentation so that it is stepbystep. Polls, data mining surveys, and studies of scholarly literature databases show substantial increases in popularity. See the document writing r extensions for the available markup commands you should have consulted this document already if you are at the stage of documenting your software. When we pass an identi er to a function r looks for an associated object. That said, it doesnt automate the documentation in the sense that some documentation generation tools do e. The edgelist format is a simple text file, with one edge in a line, the two vertex ids separated by a space character.

It should be raw text or written in some very easy to read markup, such as restructuredtext or markdown. Thanks for contributing an answer to stack overflow. The details of model specification are given under details. A functional specification also, functional spec, specs, functional specifications document fsd, functional requirements specification in systems engineering and software development is a document that specifies the functions that a system or component must perform often part of a requirements specification isoiecieee 247652010 the documentation typically describes what is needed. R provides a standard way of documenting the objects in a package. The generic accessor functions coefficients, effects, fitted. R has a large number of inbuilt functions and the user can create their own functions. One of the great strengths of r is the users ability to add functions. You all know what a mathematical function is, like logxor. Good software documentation, whether a specifications document for programmers and testers, a technical document for internal users, or software manuals and help files for end users, helps the person working with the software understand its features and functions. It should contain a few lines explaining the purpose of the project or library without assuming the user knows anything about the project, the url of. In a subsequent one, you learned more about how to avoid looping by using the apply family of functions, which act on compound data in repetitive ways. Create help text by inserting comments at the beginning of your program.

Home how to write a good documentation library guides. Rd files use a simple markup format that syntactically resembles latex. R processes them to create plain text, pdf, and html versions. Details expression here is not being used in its colloquial sense, that of mathematical expressions. A function in r, like a mathematical function, takes zero or more inputs, also called arguments, and returns an output. The r generic function prompt is used to construct a barebones rd file ready. With power bi desktop, you can use r to visualize your data. Writing software documentation adapted from writing software documentation. I wanted to extend on that information by providing a working example of how to put together a function.

May 22, 2014 r has a fantastic package roxygen2 that makes documenting functions quite easy. R is a language and environment for statistical computing and graphics install r. Dec 17, 2019 rd files use a simple markup format that syntactically resembles latex. An object of class lm is a list containing at least the following components.

If you arent already familiar with the basics of r package development, the following links provide additional documentation and tutorials. For detailed documentation on the rd format please see the article on writing r documentation available on cran. To add documentation to an r package, you need to create a subdirectory man containing a set of files, one per function, in a special r documentation format. The file is sorted by the first and the second column. It provides a wide variety of statistical and graphical techniques linear and nonlinear modelling. X research source following are instructions on how to write software documentation for technical users and end users. These files use a custom syntax, loosely based on latex, and are rendered to html, plain text and pdf for viewing. R to a separate directory called tests see for example the stringr package. Since you ran the code through the console, the function is now available, like any of the other builtin functions within r. It should generally fit on one line, be written in sentence case, and not end in a full stop. A readme file at the root directory should give general information to both users and maintainers of a project. A function is a set of statements organized together to perform a specific task.

I soon turned to writing for a creative outlet as a way to add a splash of color to the back and white world in which i coexisted with physics. Documenting functions now, lets consider the documentation for. The default value file prints the initial draft in the console, instead of writing it to a file. In r, there are builtin functions like summary or glm or median, but you can also write your own functions. Writing documentation will start you down the road to being a better technical writer, which is a useful skill to have as a. In larger or more complex projects however, it is often a good idea to give more information about a function, what it does, any exceptions it may raise, what it returns, or relevant details about the parameters. Computer documentation, when done correctly, enhances the value of the software described by making it easier to use and therefore more accessible. Writing documentation is not rocket science, you are not designing the fuel nor the engine, nor do you need to perform physics calculations. Jun 18, 2018 to use the testthat package you will put a file called testareapackagename. Taking 25 minutes to write even a barebones documentation, that includes. Writing tools for software documentation process street. The r language is widely used among statisticians and data miners for developing statistical software and data analysis. You may also want to try compiling with a very simple function rst e.

Which is the best way to write software documentation. I then enrolled in writingbased physics and math classes, where i realized that i. R in action 2nd ed significantly expands upon this material. R can be regarded as an implementation of the s language which was developed at bell laboratories by rick becker, john chambers and allan wilks, and also forms the basis of the splus systems the evolution of the s language is characterized by four books by john chambers and coauthors. Sample texts from an r session are highlighted with gray shading. Documentation is an important part of software engineering. It is used throughout development to communicate how the software functions or how it is intended to operate. This example shows how to provide help for the programs you write. In my view from a software developers perspective, there are four levels of documentation. In addition to the specific markup commands to be described, you can create an initial, overall file with a skeleton of documentation for the methods defined for a. Expression here is not being used in its colloquial sense, that of mathematical expressions. A massive part of statistical software development is the documentation. R is similar to the awardwinning 1 s system, which was developed at bell laboratories by john chambers et al. Aug 24, 2016 writing tools for software documentation.

Define the function, load the function into the r session, use the function. We have made a number of small changes to reflect differences between the r. The best way to learn to swim is by jumping in the deep end, so lets just write a function to show you how easy that is in r. Create power bi visuals using r power bi microsoft docs. In particular, i will walk through the process of generating a function that executes evaluation of a time continue reading writing functions in r. That said, it doesnt automate the documentation in the sense that some documentationgeneration tools do e. Software documentation is often written in markdown to allow for hyperlinks and formatting while keeping it plain text so it can live alongside the code files in version control. Instead of writing these files by hand, were going to use roxygen2 which turns specially formatted comments into. R is a programming language and free software environment for statistical computing and graphics supported by the r foundation for statistical computing. A beginners guide to writing documentation write the docs. Requirements documentation is the description of what a particular software does or shall do. These will be the source for the documentation for each function. But avoid asking for help, clarification, or responding to other answers. Older versions of the manual can be found in the respective.