Most R functions have online documentation.

• help(topic) documentation on topic
• ?topic id.
• help.search(“topic”) search the help system
• apropos(“topic”) the names of all objects in the search list matching the regular expression ”topic”
• help.start() start the HTML version of help
• str(a) display the internal *str*ucture of an R object
• summary(a) gives a “summary” of a, usually a statistical summary but it is generic meaning it has different operations for different classes of a
• ls() show objects in the search path; specify pat=”pat” to search on a
• pattern
• ls.str() str() for each variable in the search path
• dir() show files in the current directory
• methods(a) shows S3 methods of a
• methods(class=class(a)) lists all the methods to handle objects of class a