To obtain online help for any command type help command. Machine Numerical Characteristics of the Machine Description. As neg. Typically, it is equal to 1 - neg. Machine 5 double. Will be zero if there is no such type. Machine sizeof. References Cody, W. Transactions on Mathematical Software, 14, 4, — See Also. Platform for details of the platform.
Examples str. Machine base —. Platform is a list with some details of the platform under which R was built. This provides means to write OS portable R code. Platform Value A list with at least the following components: OS. One of "unix" or "windows". See Also R. In particular, R. Examples Note: this can be done in a system-independent way by file.
This is a list with one component for each dimension, either NULL or a character vector of the length given by dim for that dimension. The list can be names, and the names will be used as names for the dimensions. The values in data are taken to be those in the array with the leftmost subscript moving fastest.
It also attaches dimnames if x has names. The sole purpose of this is to make it possible to access the dim[names] attribute at a later time. See Also aperm, matrix, dim, dimnames. Examples dim as. By default, all packages in the search path are used. The default value of NULL corresponds to all libraries currently known.
If the default is used, the loaded packages are searched before the libraries. Details If lib. If lib. An attempt is made to load the package before running the examples, but this will not replace a package loaded from another location. As detailed in the manual Writing R Extensions, the author of the help page can markup parts of the examples for two exception rules dontrun encloses code that should not be run.
This was previously testonly, and that form is still accepted. Value the value of the last evaluated expression. Description Search for an R object of the given name on the search path.
Equivalent to giving where as sys. Details The where argument can specify the environment in which to look for the object in any of several ways: as an integer the position in the search list ; as the character string name of an element in the search list; or as an environment including using sys.
The envir argument is an alternative way to specify an environment, but is primarily there for back compatibility. This function looks to see if the name x has a value bound to it.
If inherits is TRUE and a value is not found for x, then the parent frames of the environment are searched until the name x is encountered. Warning: This is the default behaviour for R but not for S. Value Logical, true if and only if the object is found on the search path. References Becker, R. See Also get. Examples Define a substitute function if necessary: if! For example, [[:alnum:]] means [A-Za-z], except the latter depends upon the locale and the character encoding, whereas the former is independent of locale and character set.
Note that the brackets in these class names are part of the symbolic names, and must be included in addition to the brackets delimiting the bracket list. Most metacharacters lose their special meaning inside lists. The period. The preceding item is optional and will be matched at most once. Repetition is greedy, so the maximal possible number of repeats is used. Two regular expressions may be concatenated; the resulting regular expression matches any string formed by concatenating two substrings that respectively match the concatenated subexpressions.
For example, abba cde matches either the string abba or the string cde. Note that alternation does not work inside character classes, where has its literal meaning. Repetition takes precedence over concatenation, which in turn takes precedence over alternation. A whole subexpression may be enclosed in parentheses to override these precedence rules. POSIX allows this behaviour as an extension but we advise users not to rely on it. Thus the metacharacters are.
There can be more than 9 backreferences. The construct? Perl-like matching can work in several modes, set by the options? These can be concatenated, so for example,?
It is also possible to unset these options by preceding the letter with a hyphen, and to combine setting and unsetting such as? These settings can be applied within patterns, and then apply to the remainder of the pattern. Additional options not in Perl include? Initially none of these options are set. In PCRE 3. The base package commands are automatically available when the R environment is started.
The second companion volume 'The R Reference Manual - Base Package - Volume 2' ISBN contains documentation for commands for graphics, mathematics, distributions and random numbers, models, time-series and datasets. Together the first and second volumes document the complete base package of R version 1. All the reference manuals are written by the developers of R, and represent the definitive guide to the software.
The manuals explain the use of each command in detail, with references, implementation notes and examples. Every volume includes a comprehensive index of entries listed by keyword and topic. NOTE: You need both volumes for the complete documentation. The individual volumes are not intended to be used on their own.
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