Functions
You have used a few functions already. Here is just a bit more formal introduction. You should be able to understand the inputs (arguments) you specify when calling a function and the output it returns. For most functions, you can get help by executing ?function_name in the console.
Getting help with functions and features
R has an inbuilt help facility similar to the man facility of
UNIX. To get more information on any specific named function, for
example solve, the command is
> help(solve)
An alternative is
> ?solve
For a feature specified by special characters, the argument must be
enclosed in double or single quotes, making it a "character string":
This is also necessary for a few words with syntactic meaning including
if, for and function.
> help("[[")
Either form of quote mark may be used to escape the other, as in the
string "It's important". Our convention is to use
double quote marks for preference.
On most R installations help is available in HTML format by running
> help.start()
which will launch a Web browser that allows the help pages to be browsed
with hyperlinks. On UNIX, subsequent help requests are sent to the
HTML-based help system. The ‘Search Engine and Keywords' link in the
page loaded by help.start() is particularly useful as it is
contains a high-level concept list which searches though available
functions. It can be a great way to get your bearings quickly and to
understand the breadth of what R has to offer.
The help.search command (alternatively ??)
allows searching for help in various
ways. For example,
> ??solve
Try ?help.search for details and more examples.
The examples on a help topic can normally be run by
> example(topic)
Windows versions of R have other optional help systems: use
> ?help
for further details.
Source: R Core Team, https://cran.r-project.org/doc/manuals/r-release/R-intro.html#Getting-help
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