! | Not operator. |

!= | Not equal operator. |

$, $<- | Select or set named element from a list. |

%% | Modulo operator. |

%*% | Binary operator to multiply two matrices, ifthey are conformable. |

%/% | Integer division operator. |

%in% | Binary operator that returns a logical vectorindicating if there is a match or not for its left operand. |

%o% | Operator to calculate the outer product of twoarrays. |

%x% | Operator to calculate the Kronecker product oftwo arrays. |

& | Operator that performs elementwise logicalAND. |

&& | Operator that performs logical AND, evaluatingexpressions from left to right until the result isdetermined. |

* | Multiplication operator. |

+ | Addition operator. |

- | Unary negation or binary subtractionoperator. |

/ | Binary division operator. |

: | Generates regular sequences. |

:: | Accesses an exported variable in anamespace. |

::: | Accesses an internal variable in a namespace. |

< | Less-than operator. |

> | Greater-than operator. |

>= | Greater-than-or-equal-to operator. |

<= | Less-than-or-equal-to operator. |

== | Equality operator. |

@ | Extracts the contents of an slot in an objectwith a formal (S4) class structure. |

Arg | Returns argument of a complex value. |

Conj | Returns conjugate of a complex value. |

Cstack_info | Reports information on the C stack size and usage (ifavailable). |

Encoding, Encoding<- | Read or set the declared encodings for a charactervector. |

Filter | Extracts the elements of a vector for which a predicate(logical) function gives true. |

Find | Returns the first or last element in a vector for whicha condition is true. |

I | Changes the class of an object to indicate that itshould be treated "as is." |

ISOdate, ISOdatetime | Functions to convert between character representationsand objects of classes `"POSIXlt"` and `"POSIXct"` representing calendardates and times. |

Im | Extracts the imaginary part of a complex value. |

La.svd | Computes the singular-value decomposition of arectangular matrix. |

Map | Applies a function to the corresponding elements ofgiven vectors. |

Mod | Returns the modulus of a complex number. |

NCOL, NROW | `nrow` and `ncol` return the number of rows orcolumns present in `x` .`NCOL` and `NROW` do the same, treating a vectoras one-column matrix. |

Negate | Creates the negation of a given function. |

NextMethod | For S3 generic functions, dispatches to the method forthe next class in the object's class vector. |

Position | Gives the position of an element in a matrix for whicha predicate (logical) function is true. |

R.Version | Provides detailed information about the version of Rrunning. |

R.home | Returns the R home directory. |

RNGkind | Allows you to query or set the kind of random numbergenerator (RNG) in use. |

RNGversion | Can be used to set the random number generators as theywere in an earlier R version (for reproducibility). |

R_system_version | Simple S3 class for representing numeric versions, including package versions, and associated methods. |

Re | Returns the real part of a complex number. |

Recall | Used as a placeholder for the name of the function inwhich it is called. It allows the definition of recursivefunctions that still work after being renamed. |

Reduce | Uses a binary function to successively combine theelements of a given vector and a possibly given initialvalue. |

Sys.Date, Sys.time | Return the system's idea of the current date with andwithout time. |

Sys.chmod | Provides a low-level interface to the computer's filesystem. |

Sys.getenv | Obtains the values of the environmentvariables. |

Sys.getlocale | Gets details of or sets aspects of the locale for the Rprocess. |

Sys.getpid | Gets the process ID of the R session. |

Sys.glob | Performs wildcard expansion (also known as "globbing")on file paths. |

Sys.info | Reports system and user information. |

Sys.localeconv | Gets details of the numerical and monetaryrepresentations in the current locale. |

Sys.setenv | Sets environment variables (for other processes calledfrom within R or future calls to `Sys.getenv` from this Rprocess). |

Sys.setlocale | Gets details of or sets aspects of the locale for the Rprocess. |

Sys.sleep | Suspends execution of R expressions for a given numberof seconds. |

Sys.timezone | Returns the current time zone. |

Sys.umask | Provides a low-level interface to the computer's filesystem. |

Sys.unsetenv | Removes environment variables. |

Sys.which | Interface to the system command `which` . |

UseMethod | Dispatches to the appropriate method for an S3 genericfunction. |

Vectorize | Returns a new function that acts as if `mapply` was called. |

^ | Exponentiation operator. |

abbreviate | Abbreviates strings to at least `minlength` characters, such that theyremain *unique* (if they were), unless`strict=TRUE` . |

abs | Absolute value. |

acos | Computes the arccosine. |

acosh | Computes the hyperbolic arccosine. |

addNA | Modifies a factor by turning NA into an extra level (sothat NA values are counted in tables, for instance). |

addTaskCallback | Registers an R function that is to be called each timea top-level task is completed. |

agrep | Searches for approximate matches to `pattern` (the first argument) withinthe string `x` (the secondargument) using the Levenshtein edit distance. |

alist | Function to construct, coerce, and check for both kindsof R lists. |

all | Given a set of logical vectors, are all of the valuestrue? |

all.equal | `all.equal(x, y)` is autility to compare R objects `x` and `y` testing "near equality." If theyare different, comparison is still made to some extent, and areport of the differences is returned. |

all.names, all.vars | Return a character vector containing all the names thatoccur in an expression or call. |

any | Given a set of logical vectors, is at least one of thevalues true? |

anyDuplicated | Determines which elements of a vector or data frame areduplicates of elements with smaller subscripts and returns alogical vector indicating which elements (rows) areduplicates. |

aperm | Transposes an array by permuting its dimensions andoptionally resizing it. |

append | Adds elements to a vector. |

apply | Returns a vector or array or list of values obtained byapplying a function to margins of an array. |

args | Displays the argument names and corresponding defaultvalues of a function or primitive. |

array | Creates arrays. |

as.Date | Function to convert between character representationsand objects of class `"Date"` representing calendar dates. |

as.POSIXct, as.POSIXlt | Functions to manipulate objects of classes `"POSIXlt"` and `"POSIXct"` representing calendardates and times. |

as.array | Coerces to arrays. |

as.call | Coerces to "call" objects. |

as.character | Coerces to "character" objects. |

as.complex | Coerces to "complex" objects. |

as.data.frame | Coerces to "data.frame" objects. |

as.difftime | Coerces to "difftime" objects. |

as.double | Coerces to "double" objects. |

as.environment | Converts a number or a character string to thecorresponding environment on the search path. |

as.expression | Coerces to "expression" objects. |

as.factor | Coerces to "factor". |

as.function | Coerces to "function". |

as.hexmode | Coerces to "hexmode". |

as.integer | Creates or tests for objects of type "integer". |

as.list | Coerces to "list". |

as.logical | Coerces to "logical" objects. |

as.matrix | Coerces to "matrix" objects. |

as.name | Coerces to "name" objects. |

as.null | Ignores its argument and returns the value `NULL` . |

as.numeric | Coerces to "numeric". |

as.numeric_version | Coerces to "numeric_version". |

as.octmode | Coerces to "octmode". |

as.ordered | Coerces to ordered factors. |

as.package_version | Coerces to "package_version" object. |

as.pairlist | Coerces to "pairlist" object. |

as.raw | Coerces to type "raw". |

as.real | Coerces to type "real". |

as.symbol | Coerces to "symbol". |

as.table | Coerces to "table". |

as.vector | Coerces to "vector". |

asS4 | Tests whether the object is an instance of an S4class. |

asin | Computes the arcsine. |

asinh | Computes the hyperbolic arcsine. |

assign | Assigns a value to a name in an environment. |

atan | Computes the arctangent. |

atan2 | Computes the two-argument arctangent. |

atanh | Computes the hyperbolic arctangent. |

attach | Attaches a database (usually a list, data frame, orenvironment) to the R search path. This means that thedatabase is searched by R when evaluating a variable, soobjects in the database can be accessed by simply giving theirnames. |

attachNamespace | Function to load and unload namespaces. |

attr, attr<- | Get or set specific attributes of an object. |

attributes, attributes<- | Access an object's attributes. |

autoload, autoloader | `autoload` creates apromise-to-evaluate `autoloader` and stores it with name`name` in the`.AutoloadEnv` environment. |

backsolve | Solves a system of linear equations where thecoefficient matrix is upper or lower triangular. |

baseenv | Gets, sets, tests for, and createsenvironments. |

basename | Removes all of the path up to the last path separator(if any). |

besselI, besselJ, besselK, besselY | Bessel functions of integer and fractional order, offirst and second kind, *J*(*υ*) and*Y*(*υ*), and modifiedBessel functions (of first and third kind), *I*(*υ*) and*K*(*υ*). |

beta | Special mathematical function related to the beta andgamma functions. |

bindingIsActive, bindingIsLocked | These functions represent an experimental interface foradjustments to environments and bindings within environments.They allow for locking environments as well as individualbindings and for linking a variable to a function. |

bindtextdomain | If Native Language Support was enabled in this build ofR, attempts to translate character vectors or sets where thetranslations are to be found. |

body, body<- | Get or set the body of a function. |

bquote | Analog of the LISP backquote, macro. `bquote` quotes its argument exceptthat terms wrapped in `.()` are evaluated in the specified `where` environment. |

break | Basic control-flow constructs of the R language. Theyfunction in much the same way as control statements in anyAlgol-like language. They are all reserved words. |

browser | Interrupts the execution of an expression and allowsthe inspection of the environment where `browser` was called from. |

builtins | Returns the names of all the built-in objects. Theseare fetched directly from the symbol table of the Rinterpreter. |

by | An object-oriented wrapper for `tapply` applied to dataframes. |

bzfile | Function to create, open, and closeconnections. |

c | Combines its arguments. |

call | Creates or tests for objects of mode "call". |

callCC | Downward-only version of Scheme's call with currentcontinuation. |

capabilities | Reports on the optional features that have beencompiled into this build of R. |

casefold | Translates characters in character vectors, inparticular, from upper- to lowercase or vice versa. |

cat | Outputs the objects, concatenating the representations.`cat` performs much lessconversion than `print` . |

cbind | Takes a sequence of vector, matrix, or data framearguments and combines by columns. |

ceiling | Takes a single numeric argument `x` and returns a numeric vectorcontaining the smallest integers not less than thecorresponding elements of `x` . |

char.expand | Seeks a unique match of its first argument among theelements of its second. If successful, it returns thiselement; otherwise, it performs an action specified by thethird argument. |

charToRaw | Conversion and manipulation of objects of type"raw". |

character | Creates or tests for objects of type"character". |

charmatch | Seeks matches for the elements of its first argumentamong those of its second. |

chartr | Translates characters in character vectors, inparticular, from upper- to lowercase or vice versa. |

check_tzones | Description of the classes `"POSIXlt"` and `"POSIXct"` representing calendardates and times (to the nearest second). |

chol | Computes the Choleski factorization of a real, symmetric, positive-definite square matrix. |

chol2inv | Inverts a symmetric, positive-definite square matrixfrom its Choleski decomposition. Equivalently, computes(*X'X*)^{-1} fromthe (*R* part) of the*QR*-decomposition of*X*. |

choose | Special mathematical function related to the beta andgamma functions. |

class, class<- | The function `class` prints the vector of names of classes an object inherits from.Correspondingly, `class<-` sets the classes an object inherits from. |

close, close.connection | Close connections. |

closeAllConnections | Displays aspects of connections. |

col | Returns a matrix of integers, indicating their columnnumber in a matrix-like object or a factor of columnlabels. |

colMeans | Forms row and column means for numeric arrays. |

colSums | Forms row and column sums for numeric arrays. |

colnames, colnames<- | Retrieve or set the row or column names of amatrix-like object. |

commandArgs | Provides access to a copy of the command-line argumentssupplied when this R session was invoked. |

comment, comment<- | Set and query a *comment* attributefor any R objects. |

computeRestarts | Provides a mechanism for handling unusual conditions, including errors and warnings. |

conditionCall, conditionCall.condition, conditionMessage, conditionMessage.condition | Provide a mechanism for handling unusual conditions, including errors and warnings. |

conflicts | Reports on objects that exist with the same name in twoor more places on the `search` path, usually because anobject in the user's workspace or a package is masking asystem object of the same name. This helps discoverunintentional masking. |

contributors | The R Who's Who, describing who made significantcontributions to the development of R. |

crossprod | Given matrices `x` and`y` as arguments, returns amatrix cross-product. This is formally equivalent to (butusually slightly faster than) the call `t(x) \%*\% y` . |

cummax, cummin, cumprod, cumsum | Returns a vector whose elements are the cumulativesums, products, minima, or maxima of the elements of theargument. |

cut | Divides the range of `x` into intervals and codes thevalues in `x` according towhich interval they fall. The leftmost interval corresponds tolevel 1, the next leftmost to level 2 and so on. |

cut.Date, cut.POSIXt | Method for `cut` applied to date-time objects. |

dQuote | Single- or double-quote text by combining withappropriate single or double left and right quotationmarks. |

data.class | Determines the class of an arbitrary R object. |

data.frame | Creates data frames. |

data.matrix | Returns the matrix obtained by converting all thevariables in a data frame to numeric mode and then bindingthem together as the columns of a matrix. Factors and orderedfactors are replaced by their internal codes. |

date | Returns a character string of the current system dateand time. |

debug | Sets, unsets, or queries the debugging flag on afunction. |

default.stringsAsFactors | Creates data frames, tightly coupled collections ofvariables that share many of the properties of matrices andlists, used as the fundamental data structure by most of R'smodeling software. |

delayedAssign | Creates a *promise* to evaluate agiven expression if its value is requested. This providesdirect access to the *lazy evaluation*mechanism used by R for the evaluation of (interpreted)functions. |

deparse | Turns unevaluated expressions into characterstrings. |

det, determinant | `det` calculates thedeterminant of a matrix. `determinant` is a generic functionthat returns separately the modulus of the determinant, optionally on the logarithm scale, and the sign of thedeterminant. |

detach | Detaches a database, i.e., removes it from the `search()` path of available Robjects. Usually, this is either a `data.frame` that has been `attach` ed or a package that wasrequired previously. |

dget | Writes an ASCII (American Standard Code for InformationInterchange) text representation of an R object to a file orconnection or uses one to re-create the object. |

diag, diag<- | Extract or replace the diagonal of a matrix orconstruct a diagonal matrix. |

diff, diff.Date, diff.POSIXt, diff.default | Return suitably lagged and iterateddifferences. |

difftime | Creates, prints, and rounds time intervals. |

digamma | Special mathematical function related to the beta andgamma functions. |

dim, dim.data.frame, dim<-, dimnames, dimnames.data.frame, dimnames<-, dimnames<-.data.frame | Retrieve or set the dimension of an object. |

dir, dir.create | Produce a character vector of the names of files in thenamed directory. |

dirname | Returns the part of the `path` up to (but excluding) the lastpath separator, or `"."` ifthere is no path separator. |

do.call | Constructs and executes a function call from a name ora function and a list of arguments to be passed to it. |

double | Creates, coerces to, or tests for a double-precisionvector. |

dput | Writes an ASCII text representation of an R object to afile or connection or uses one to re-create theobject. |

drop | Deletes the dimensions of an array that has only onelevel. |

dump | Takes a vector of names of R objects and produces textrepresentations of the objects on a file or connection. A`dump` file can usually be`source` d into another R (orS) session. |

duplicated | Determines which elements of a vector or data frame areduplicates of elements with smaller subscripts and returns alogical vector indicating which elements (rows) areduplicates. |

dyn.load, dyn.unload | Load or unload DLLs (also known as shared objects) andtest whether a C function or FORTRAN subroutine isavailable. |

eapply | Applies `FUN` to thenamed values from an environment and returns the results as alist. |

eigen | Computes eigenvalues and eigenvectors of real orcomplex matrices. |

emptyenv | Gets, sets, tests for, and createsenvironments. |

encodeString | Escapes the strings in a character vector in the sameway `print.default` does andoptionally fits theencoded strings within a field width. |

env.profile | This function is intended to assess the performance ofhashed environments. |

environment, environment<- | Gets or sets the environment associated with a functionor formula. |

environmentIsLocked | Returns a logical environment indicating if anenvironment is locked. |

environmentName | Returns the name of an environment. |

eval, eval.parent, evalq | Evaluate an R expression in a specifiedenvironment. |

exists | Looks for an R object of a given name. |

exp | Computes the exponential function. |

expand.grid | Creates a data frame from all combinations of thesupplied vectors or factors. |

expm1 | Computes*e*^{x} − 1accurately for *x* << 1. |

expression | Creates objects of mode `"expression"` . |

factor | Used to encode a vector as a factor. |

factorial | Special mathematical function related to the beta andgamma functions. |

fifo | Creates a FIFO connection. |

file | Creates a file connection. |

file.access | Utility function to access information about files onthe user's file systems. |

file.append | Provides a low-level interface to the computer's filesystem. |

file.choose | Chooses a file interactively. |

file.copy, file.create, file.exists | Provide a low-level interface to the computer's filesystem. |

file.info | Utility function to extract information about files onthe user's file systems. |

file.path | Constructs the path to a file from components in aplatform-independent way. |

file.remove, file.rename | Provides a low-level interface to the computer's filesystem. |

file.show | Displays one or more files. |

file.symlink | Provides a low-level interface to the computer's filesystem. |

findInterval | Finds the indices of `x` in `vec` , where `vec` must be sorted(nondecreasingly). |

findRestart | Provides a mechanism for handling unusual conditions, including errors and warnings. |

floor | Takes a single numeric argument `x` and returns a numeric vectorcontaining the largest integers not greater than thecorresponding elements of `x` . |

flush, flush.connection | Functions to create, open, and closeconnections. |

force | Forces the evaluation of a function argument. |

formals, formals<- | Get or set the formal arguments of a function. |

format, format.AsIs | Format an R object for pretty printing. |

formatC | Formats numbers individually and flexibly, using`C` -style formatspecifications. |

formatDL | Formats vectors of items and their descriptions astwo-column tables or LaTeX-style description lists. |

forwardsolve | Solves a system of linear equations where thecoefficient matrix is upper or lower triangular. |

function | Provides the base mechanisms for defining new functionsin the R language. |

gamma | Special mathematical function related to the beta andgamma functions. |

gc | Causes garbage collection to take place. |

gc.time | Reports the time spent in garbage collection so far inthe R session while GC timing was enabled. |

gcinfo | Sets a flag so that automatic collection is eithersilent (`verbose=FALSE` ) orprints memory usage statistics (`verbose=TRUE` ). |

gctorture | Provokes garbage collection on (nearly) every memoryallocation. Intended to ferret out memory protection bugs.Also makes R run *very* slowly, unfortunately. |

get | Searches for an R object with a given name and returnsit. |

getAllConnections | Displays aspects of connections. |

getCConverterDescriptions, getCConverterStatus | Provide facilities to manage the extensible list ofconverters used to translate R objects into C pointers for usein `.C` calls. The number anda description of each element in the list can be retrieved.One can also query and set the activity status of individualelements, temporarily ignoring them. And one can removeindividual elements. |

getConnection | Displays aspects of connections. |

getDLLRegisteredRoutines, getDLLRegisteredRoutines.DLLInfo, getDLLRegisteredRoutines.character | These functions allow us to query the set of routinesin a DLL that are registered with R to enhance dynamic lookup, error handling when calling native routines, and potentiallysecurity in the future. These functions provide a descriptionof each of the registered routines in the DLL for thedifferent interfaces, i.e., `.C` , `.Call` , `.Fortran` , and `.External` . |

getExportedValue | Function to support reflection on namespaceobjects. |

getHook | Allows users to set actions to be taken before packagesare attached/detached and namespaces are (un)loaded. |

getLoadedDLLs | Provides a way to get a list of all the DLLs (see`dyn.load` ) that arecurrently loaded in the R session. |

getNamespace, getNamespaceExports, getNamespaceImports, getNamespaceName, getNamespaceUsers, getNamespaceVersion | Functions to support reflection on namespaceobjects. |

getNativeSymbolInfo | Finds and returns as comprehensive a description of oneor more dynamically loaded or "exported" built-in nativesymbols. |

getNumCConverters | Used to manage the extensible list of converters usedto translate R objects into C pointers for use in `.C` calls. Returns an integer givingthe number of elements in a specified list, both active andinactive. |

getOption | Allows the user to set and examine a variety of global*options* that affect the way in which Rcomputes and displays its results. |

getRversion | A simple S3 class for representing numeric versions, including package versions, and associated methods. |

getSrcLines | This function is for working with source files. |

getTaskCallbackNames | Provides a way to get the names (or identifiers) forthe currently registered task callbacks that are invoked atthe conclusion of each top-level task. These identifiers canbe used to remove a callback. |

geterrmessage | Gives the last error message. |

gettext | If Native Language Support was enabled in this build ofR, attempts to translate character vectors or set where thetranslations are to be found. |

gettextf | A wrapper for the C function `sprintf` that returns a charactervector containing a formatted combination of text and variablevalues. |

getwd | Returns an absolute filename representing the currentworking directory of the R process. |

gl | Generates factors by specifying the pattern of theirlevels. |

globalenv | Gets, sets, tests for, and createsenvironments. |

gregexpr, grep, grepl, gsub | `grep` searches formatches to `pattern` (itsfirst argument) within the character vector `x` (second argument). `grepl` is an alternative way toreturn the results. `regexpr` and `gregexpr` return results, too, but they return more detail in a differentformat. |

gsub | `sub` and `gsub` perform replacement of matchesdetermined by regular expression matching. |

gzcon | Provides a modified connection that wraps an existingconnection and decompresses reads or compresses writes throughthat connection. Standard `gzip` headers are assumed. |

gzfile | Function to create, open, and closeconnections. |

iconv, iconvlist | These use system facilities to convert a charactervector between encodings: the "i" stands for"internationalization." |

icuSetCollate | Controls the way collation is done by ICU (an optionalpart of the R build). |

identical | The safe and reliable way to test two objects for being*exactly* equal. It returns `TRUE` in this case, `FALSE` in every other case. |

identity | A trivial identity function returning itsargument. |

ifelse | Returns a value with the same shape as `test` that is filled with elementsselected from either `yes` or`no` , depending on whetherthe element of `test` is`TRUE` or `FALSE` . |

inherits | Indicates whether its first argument inherits from anyof the classes specified in the what argument. |

intToBits | Conversion and manipulation of objects of type `"raw"` . |

intToUtf8 | Conversion of UTF-8 encoded character vectors to andfrom integer vectors. |

integer | Creates or tests for objects of type `"integer"` . |

interaction | Computes a factor that represents the interaction ofthe given factors. The result of `interaction` is alwaysunordered. |

interactive | Returns `TRUE` when Ris being used interactively and `FALSE` otherwise. |

intersect | Performs *set* union, intersection, (asymmetric!) difference, equality, and membership on twovectors. |

inverse.rle | Computes the lengths and values of runs of equal valuesin a vector—or the reverse operation. |

invisible | Returns a (temporarily) invisible copy of anobject. |

invokeRestart, invokeRestartInteractively | Provide a mechanism for handling unusual conditions, including errors and warnings. |

is.R | Tests if running under R. |

is.array | Creates or tests for arrays. |

is.atomic | Returns `TRUE` if`x` is an atomic vector (or`NULL` ) and `FALSE` otherwise. |

is.call | Tests for objects of mode "call". |

is.character | Tests for objects of type "character". |

is.complex | Tests for objects of type "complex". |

is.data.frame | Tests if an object is a data frame. |

is.double | Tests for a double-precision vector. |

is.element | Tests if an element is a member of a set. |

is.environment | Tests if an object is an environment. |

is.expression | Tests if an object is an "expression". |

is.factor | Returns a logical value indicating if an object is afactor. |

is.finite, is.infinite | Return a vector of the same length as `x` , indicating which elements arefinite (not infinite and not missing). |

is.function | Checks whether its argument is a (primitive)function. |

is.integer | Creates or tests for objects of type "integer". |

is.language | Returns `TRUE` if`x` is a variable `name` , a `call` , or an `expression` . |

is.list | Tests if an object is a list. |

is.loaded | Tests whether a C function or FORTRAN subroutine isavailable. |

is.logical | Tests for objects of type "logical". |

is.matrix | Tests if its argument is a (strict) matrix. |

is.na, is.na<- | The generic function `is.na` indicates which elements in anobject are missing. The generic function `is.na<-` sets elements to `NA` . |

is.name | Returns `TRUE` or`FALSE` , depending on whetherthe argument is a name or not. |

is.nan | Tests if an object is a `NaN` (meaning "not anumber"). |

is.null | Returns `TRUE` if itsargument is `NULL` and`FALSE` otherwise. |

is.numeric, is.numeric.Date, is.numeric.POSIXt | A general test of an object being interpretable asnumbers. |

is.numeric_version | A simple S3 class for representing numeric versions, including package versions, and associated methods. |

is.ordered | Tests if an object is an ordered factor. |

is.package_version | Tests for a package_version object. |

is.pairlist | Tests for a pairlist object. |

is.primitive | Checks whether its argument is a (primitive)function. |

is.qr | Tests whether an object is the*QR*-decomposition of a matrix (created bythe `qr` function). |

is.raw | Tests for objects of type `"raw"` . |

is.recursive | Returns `TRUE` if`x` has a recursive(listlike) structure and `FALSE` otherwise. |

is.symbol | `is.symbol` (and theidentical `is.name)` returns`TRUE` or `FALSE` , depending on whether theargument is a name or not. |

is.table | `table` uses thecross-classifying factors to build a contingency table of thecounts at each combination of factor levels. |

is.unsorted | Tests if an object is not sorted, without the cost ofsorting it. |

is.vector | Returns `TRUE` if`x` is a vector (of modelogical, integer, real, complex, character, raw or a list ifnot specified) or expression and `FALSE` otherwise. |

isIncomplete, isOpen | Functions to create, open, and closeconnections. |

isRestart | Provides a mechanism for handling unusual conditions, including errors and warnings. |

isS4 | Tests whether the object is an instance of an S4class. |

isSeekable | Function to reposition connections. |

isSymmetric, isSymmetric.matrix | Generic functions to test if `object` is symmetric or not.Currently, only a matrix method is implemented. |

isTRUE | This operator acts on logical vectors. |

isdebugged | Sets, unsets, or queries the debugging flag on afunction. |

jitter | Adds a small amount of noise to a numericvector. |

julian, julian.Date, julian.POSIXt | Extract the weekday, month, or quarter, or the Juliantime (days since some origin). These are generic functions:the methods for the internal date-time classes are documentedhere. |

kappa, kappa.defaultm, kappa.lm, kappa.qr, kappa.tri | The condition number of a regular (square) matrix isthe product of the norm of the matrix and the norm of itsinverse (or pseudoinverse) and hence depends on the kind ofmatrix norm. `kappa()` computes an estimate of the 2-norm condition number of amatrix or of the *R* matrix of a*QR*-decomposition, perhaps of a linearfit. The 2-norm condition number can be shown to be the ratioof the largest to the smallest *nonzero*singular value of the matrix. |

kronecker | Computes the generalized Kronecker product of twoarrays, `X` and `Y` . `\%x\%` is an alias for `kronecker` (where `FUN` is hardwired to `"*"` ). |

l10n_info | Reports on localization information. |

labels | Finds a suitable set of labels from an object for usein printing or plotting, for example. |

lapply | Returns a list of the same length as `X` , each element of which is theresult of applying `FUN` tothe corresponding element of `X` . |

lazyLoad | Lazy loads a database of R objects. |

lbeta, lchoose | Special mathematical functions related to the beta andgamma functions. |

length, length<-, length<-.factor | Get or set the length of vectors (including lists) andfactors and of any other R object for which a method has beendefined. |

levels, levels.default, levels<-, levels<-.factor | Provide access to the levels attribute of avariable. |

lfactorial, lgamma | Special mathematical functions related to the beta andgamma functions. |

library | `library` and `require` load add-onpackages. |

library.dynam | Loads a specified file of compiled code if it has notbeen loaded already, or unloads it. |

library.dynam.unload | Loads a specified file of compiled code if it has notbeen loaded already, or unloads it. |

licence | The license terms under which R is distributed. |

list | Function to construct, coerce, and check for both kindsof R lists. |

list.files | Produces a character vector of the names of files inthe named directory. |

load | Reloads data sets written with the function `save` . |

loadNamespace | Loads the specified namespace and registers it in aninternal database. |

loadedNamespaces | Returns a character vector of the names of the loadednamespaces. |

loadingNamespaceInfo | Returns a list of the arguments that would be passed to.onLoad when a namespace is being loaded. |

local | Evaluates an R expression in a specifiedenvironment. |

lockBinding | Locks individual bindings in a specifiedenvironment. |

lockEnvironment | Locks its environment argument, which must be a normalenvironment (not base). |

log | Computes logarithms, by default naturallogarithms. |

log10 | Computes common (i.e., base 10) logarithms. |

log1p | Computes log(1 + *x*) accurately for*|x| * << 1 (and less accurately when*x ≈* −1). |

log2 | Computes binary (i.e., base 2) logarithms. |

logical | Creates or tests for objects of type `"logical"` and the basic logicalconstants. |

lower.tri | Returns a matrix of logicals the same size of a givenmatrix with entries `TRUE` inthe lower or upper triangle. |

ls | `ls` and `objects` return a vector of characterstrings giving the names of the objects in a specifiedenvironment. |

make.names | Makes syntactically valid names out of charactervectors. |

make.unique | Makes the elements of a character vector unique byappending sequence numbers to duplicates. |

makeActiveBinding | Installs fun so that getting the value of sym calls funwith no arguments, and assigning to sym calls fun with oneargument, the value to be assigned. |

mapply | A multivariate version of `sapply` . `mapply` applies `FUN` to the first elements of each... argument, the second elements, the third elements, and soon. |

margin.table | For a contingency table in array form, computes the sumof table entries for a given index. |

mat.or.vec | Creates an `nr` by`nc` zero matrix if `nc` is greater than 1, and a zerovector of length `nr` if`nc` equals 1. |

match | Returns a vector of the positions of (first) matches ofits first argument in its second. |

match.arg | Matches `arg` againsta table of candidate values as specified by `choices` , where `NULL` means to take the firstone. |

match.call | Returns a call in which all of the specified argumentsare specified by their full names. |

match.fun | When called inside functions that take a function asargument, extracts the desired function object while avoidingundesired matching to objects of other types. |

matrix | Creates a matrix from a given set of values. `as.matrix` attempts to turn itsargument into a matrix. `is.matrix` tests if its argument is a(strict) matrix. |

max | Returns the (parallel) maxima and minima of the inputvalues. |

max.col | Finds the maximum position for each row of a matrix, breaking ties at random. |

mean | Generic function for the (trimmed) arithmeticmean. |

memory.profile | Lists the usage of the cons cells by `SEXPREC` type. |

merge, merge.data.frame, merge.default | Merge two data frames by common columns or row names orperform other versions of database *join*operations. |

message | Generates a diagnostic message from itsarguments. |

mget | Searches for an R object with a given name and returnsit. |

min | Returns the (parallel) maxima and minima of the inputvalues. |

missing | Tests whether a value was specified as an argument to afunction. |

mode, mode<- | Get or set the type of storage mode of anobject. |

months | Extracts the months from an object. |

mostattributes<- | The mostattributes assignment takes special care of thedim, names, and dimnames attributes and assigns them only whenvalid, whereas an attributes assignment would give an error ifany were not. |

names, names<- | Functions to get or set the names of an object. |

nargs | When used inside a function body, returns the number ofarguments supplied to that function, *including* positional arguments leftblank. |

nchar | Takes a character vector as an argument and returns avector whose elements contain the sizes of the correspondingelements of `x` . |

ncol, nrow | Return the number of rows or columns present in`x` . |

new.env | Gets, sets, tests for, and createsenvironments. |

ngettext | If Native Language Support was enabled in this build ofR, attempts to translate character vectors or set where thetranslations are to be found. |

nlevels | Returns the number of levels that its argumenthas. |

noquote | Prints character strings without quotes. |

numeric | Creates or coerces objects of type `"numeric"` . `is.numeric` is a more general test ofan object being interpretable as numbers. |

numeric_version | A simple S3 class for representing numeric versions, including package versions, and associated methods. |

nzchar | A fast way to find out if elements of a charactervector are nonempty strings. |

objects | `ls` and `objects` return a vector of characterstrings giving the names of the objects in a specifiedenvironment. |

oldClass, oldClass<- | Get and set the `class` attribute. |

on.exit | Records the expression given as its argument as needingto be executed when the current function exits (eithernaturally or as the result of an error). |

open, open.connection | Functions to create, open, and closeconnections. |

open.srcfile, open.srcfilecopy | These functions are for working with sourcefiles. |

options | Allows the user to set and examine a variety of global*options* that affect the way in which Rcomputes and displays its results. |

order | Returns a permutation that rearranges its firstargument into ascending or descending order, breaking ties byfurther arguments. |

ordered | Used to create ordered factors. |

outer | The outer product of the arrays `X` and `Y` is the array `A` with dimension `c(dim(X), dim(Y))` , where element`A[c(arrayindex.x, arrayindex.y)] =FUN(X[arrayindex.x], Y[arrayindex.y], ...)` . |

packBits | Conversion and manipulation of objects of type `"raw"` . |

packageEvent | `setHook` provides ageneral mechanism for users to register hooks, a list offunctions to be called from system (or user) functions. Theinitial set of hooks is associated with events onpackages/name spaces: these hooks are named via calls to`packageEvent` . |

packageStartupMessage | Generates a diagnostic message from itsarguments. |

package_version | Creates a package_version object (a simple S3 class forrepresenting numeric versions, including package versions, andassociated methods). |

pairlist | Function to construct, coerce, and check for both kindsof R lists. |

parent.env, parent.env<- | Get, set, test for, and create environments. |

parent.frame | Provides access to `environment` s ("frames" in Sterminology) associated with functions farther up the callingstack. |

parse | Returns the parsed but unevaluated expressions in alist. |

parseNamespaceFile | Internal namespace support function. Not intended to becalled directly. |

paste | Concatenates vectors after converting tocharacter. |

path.expand | Expands a path name, for example, by replacing aleading tilde by the user's home directory (if defined on thatplatform). |

pipe | Function to create, open, and closeconnections. |

pmatch | Seeks matches for the elements of its first argumentamong those of its second. |

pmax, pmax.int, pmin, pmin.int | Return the (parallel) maxima and minima of the inputvalues. |

polyroot | Finds zeros of a real or complex polynomial. |

pos.to.env | Returns the environment at a specified position in thesearch path. |

pretty | Computes a sequence of about `n+1` equally spaced "round" valuesthat cover the range of the values in `x` . The values are chosen so thatthey are 1, 2, or 5 times a power of 10. |

prettyNum | Formats numbers individually and flexibly, using`C` -style formatspecifications. |

print | Prints its argument and returns it*invisibly* (via `invisible(x)` ). |

prmatrix | An earlier method for printing matrices, provided for Scompatibility. |

proc.time | Determines how much real and CPU time (in seconds) thecurrently running R process has already taken. |

prod | Returns the product of all the values present in itsarguments. |

prop.table | This is really `sweep(x, margin, margin.table(x, margin), "/")` for newbies, except that if `margin` haslength 0, then one gets `x/sum(x)` . |

psigamma | Special mathematical function related to the beta andgamma functions. |

pushBack, pushBackLength | Functions to push back text lines onto a connection andto inquire about how many lines are currently pushedback. |

q | Alias for quit. |

qr | Computes the *QR*-decomposition of amatrix. It provides an interface to the techniques used in theLINPACK routine DQRDC or the LAPACK routines DGEQP3 and (forcomplex matrices) ZGEQP3. |

qr.coef | Returns the coefficients obtained when fitting y to thematrix with *QR*-decomposition qr. |

qr.qy | Returns `Q %*% y` , where `Q` is the (complete)`Q` matrix. |

qr.qty | Returns `t(Q) %*% y` , where `Q` is the (complete)`Q` matrix. |

qr.resid | Returns the residuals obtained when fitting y to thematrix with *QR*-decomposition qr. |

qr.solve | Solves systems of equations via the*QR*-decomposition: if*a* is a*QR*-decomposition, it is the same assolve.qr, but if *a* is a rectangularmatrix, the *QR*-decomposition is computedfirst. |

qr.fitted | Returns the fitted values obtained when fitting y tothe matrix with *QR*-decompositionqr. |

qr.Q, qr.R, qr.X | Returns the original matrix from which the object wasconstructed or the components of the decomposition. |

quarters | Extracts the quarter from an object. |

quit | The function `quit` orits alias `q` terminates thecurrent R session. |

quote | Simply returns its argument. The argument is notevaluated and can be any R expression. |

range | Returns a vector containing the minimum and maximum ofall the given arguments. |

rank | Returns the sample ranks of the values in a vector.Ties (i.e., equal values) and missing values can be handled inseveral ways. |

rapply | A recursive version of `lapply` . |

raw | Creates or tests for objects of type `"raw"` . |

rawConnection, rawConnectionValue | Input and output raw connections. |

rawShift, rawToBits, rawToChar | Conversion and manipulation of objects of type `"raw"` . |

rbind | Takes a sequence of vector, matrix, or data frameargument and combines by rows, respectively. |

rcond | Computes the 1- and inf-norm condition numbers for amatrix, also for complex matrices, using standard LAPACKroutines. |

read.dcf | Reads or writes an R object from/to a file in Debiancontrol file format. |

readBin | Reads binary data from a connection or writes binarydata to a connection. |

readChar | Transfers character strings to and from connections, without assuming they are null terminated on theconnection. |

readLines | Reads some or all text lines from a connection. |

readline | Reads a line from the terminal. |

real | This function is the same as its `double` equivalents and is providedfor backward compatibility only. |

reg.finalizer | Registers an R function to be called upon garbagecollection of objects or (optionally) at the end of an Rsession. |

regexpr | Searches for matches to `pattern` (its first argument) withinthe character vector `x` (second argument), and returns detailed results. |

remove, rm | Used to remove objects. |

removeCConverter | Returns TRUE if an element in the converter list wasidentified and removed. (This function provides facilities tomanage the extensible list of converters used to translate Robjects into C pointers for use in `.C` calls.) |

removeTaskCallback | Un-registers a function that was registered earlier via`addTaskCallback` . |

rep, rep.int | `rep` replicates thevalues in `x` . It is ageneric function, and the (internal) default method isdescribed here. `rep.int` isa faster simplified version for the most common case. |

replace | Replaces the values in `x` with indices given in `list` by those given in `values` . If necessary, the values in`values` arerecycled. |

replicate | A wrapper for the common use of `sapply` for repeated evaluation of anexpression (which will usually involve random numbergeneration). |

require | `library` and `require` load add-onpackages. |

retracemem | Marks an object so that a message is printed wheneverthe internal function `duplicate` is called. This happenswhen two objects share the same memory and one of them ismodified. It is a major cause of hard-to-predict memory use inR. |

return | Provides the base mechanisms for defining new functionsin the R language. |

rev | Provides a reversed version of its argument. It isgeneric function with a default method for vectors and one for`dendrograms` . |

rle | Computes the lengths and values of runs of equal valuesin a vector—or the reverse operation. |

round | Rounds the values in its first argument to thespecified number of decimal places (default 0). |

round.POSIXt | Rounds or truncates date-time objects. |

row | Returns a matrix of integers indicating their rownumber in a matrix-like object or a factor indicating the rowlabels. |

row.names, row.names<- | Get or set the row names attribute from an object (suchas a data frame). |

rowMeans, rowSums | Form row and column sums and means for numericarrays. |

rownames, rownames<- | Retrieve or set the row or column names of amatrix-like object. |

rowsum | Computes column sums across rows of a matrix-likeobject for each level of a grouping variable. |

sQuote | Single- or double-quote text by combining withappropriate single or double left and right quotationmarks. |

sample | Takes a sample of specified size from the elements of`x` using either with orwithout replacement. |

sapply | A user-friendly version of `lapply` by default returning a vectoror matrix if appropriate. |

save | Writes an external representation of R objects to aspecified file. The objects can be read back from the file ata later date by using the function `load` (or `data` in some cases). |

save.image | Just a shortcut for "save my current workspace, " i.e., `save(list = ls(all=TRUE), file =".RData")` . It is also what happens with `q("yes")` . |

saveNamespaceImage | Low-level namespace support function. |

scale | A generic function whose default method centers and/orscales the columns of a numeric matrix. |

scan | Reads data into a vector or list from the console orfile. |

search | Gives a list of `attach` ed*packages* (see `library` ), and R objects, usually`data.frames` . |

searchpaths | Gives a similar character vector to `search` , with the entries forpackages being the path to the package used to load thecode. |

seek, seek.connection | Functions to reposition connections. |

seq, seq.int, seq_along, seq_len | Generate regular sequences. `seq` is a standard generic with adefault method. `seq.int` isan internal generic that can be much faster but has a fewrestrictions. `seq_along` and`seq_len` are very fastprimitives for two common cases. |

sequence | For each element of `nvec` , the sequence `seq_len(nvec[i])` is created. Theseare concatenated and the result returned. |

serialize | A simple low-level interface for serializing toconnections. |

set.seed | The recommended way to specify seeds for randon numbergeneration. |

setCConverterStatus | Provides facilities to manage the extensible list ofconverters used to translate R objects into C pointers for usein `.C` calls. The number anda description of each element in the list can be retrieved.One can also query and set the activity status of individualelements, temporarily ignoring them. And one can removeindividual elements. |

setHook | Allows users to set actions to be taken before packagesare attached/detached and namespaces are (un)loaded. |

setSessionTimeLimit, setTimeLimit | Functions to set CPU and/or elapsed time limits fortop-level computations or the current session. |

setdiff, setequal | Perform *set* union, intersection, (asymmetric!) difference, equality, and membership on twovectors. |

setwd | Used to set the working directory to `dir` . |

shQuote | Quotes a string to be passed to an operating systemshell. |

showConnections | Displays aspects of connections. |

sign | Returns a vector with the signs of the correspondingelements of `x` (the sign ofa real number is 1, 0, or −1 if the number is positive, zero, or negative, respectively). |

signalCondition | Provides a mechanism for handling unusual conditions, including errors and warnings. |

signif | Rounds the values in its first argument to thespecified number of significant digits. |

simpleCondition, simpleError, simpleMessage, simpleWarning | Provide a mechanism for handling unusual conditions, including errors and warnings. |

sin | Computes the sine. |

sinh | Computes the hyperbolic sine. |

sink, sink.number | `sink` diverts Routput to a connection. `sink.number()` reports how manydiversions are in use. `sink.number(type = "message")` reports the number of the connection currently being used forerror messages. |

slice.index | Returns a matrix of integers indicating the number oftheir slice in a given array. |

socketConnection | Function to create, open, and closeconnections. |

socketSelect | Waits for the first of several socket connections tobecome available. |

solve | This generic function solves the equation `a \%*\% x = b` for `x` , where `b` can be either a vector or amatrix. |

solve.qr | The method of solve for qr objects. |

sort | Sorts (or *orders*) a vector orfactor (partially) into ascending (or descending)order. |

source | Causes R to accept its input from the named file or URL(the name must be quoted) or connection. |

split, split<- | `split` divides thedata in the vector `x` intothe groups defined by `f` .The replacement formsreplace values corresponding to such a division. |

sprintf | A wrapper for the C function `sprintf` that returns a charactervector containing a formatted combination of text and variablevalues. |

sqrt | Computes miscellaneous mathematical functions. Thenaming follows the standard for computer languages such as Cor FORTRAN. |

srcfile | This function is for working with source files. |

srcfilecopy | This function is for working with source files. |

srcref | This function is for working with source files. |

standardGeneric | Dispatches the method defined for a generic function`f` , using the actualarguments in the frame from which it is called. |

stderr | Displays aspects of connections. |

stdin | Displays aspects of connections. |

stdout | Displays aspects of connections. |

stop | Stops execution of the current expression and executesan error action. |

stopifnot | If any of the expressions in `...` are not `all` `TRUE` , `stop` is called, producing an errormessage indicating the *first* of theelements of `...` which werenot true. |

storage.mode, storage.mode<- | Get or set the type of storage mode of anobject. |

strftime, strptime | Functions to convert between character representationsand objects of classes `"POSIXlt"` and `"POSIXct"` representing calendardates and times. |

strsplit | Splits the elements of a character vector `x` into substrings according to thepresence of substring `split` within them. |

strtrim | Trims character strings to specified displaywidths. |

structure | Returns a given object with further attributesset. |

strwrap | Wraps character strings to format paragraphs. |

sub | Performs replacement of matches determined by regularexpression matching. |

subset | Returns subsets of vectors, matrices, or data framesthat meet conditions. |

substitute | Returns the parse tree for the (unevaluated) expression`expr` , substituting anyvariables bound in `env` . |

substr, substr<-, substring, substring<- | Extract or replace substrings in a charactervector. |

sum | Returns the sum of all the values present in itsarguments. |

summary | A generic function used to produce summaries of theresults of various model fitting. |

suppressMessages, suppressPackageStartupMessages | Generate a diagnostic message from theirarguments. |

suppressWarnings | Generates a warning message that corresponds to itsargument(s) and (optionally) the expression or function fromwhich it was called. |

svd | Computes the singular-value decomposition of arectangular matrix. |

sweep | Returns an array obtained from an input array bysweeping out a summary statistic. |

switch | Evaluates `EXPR` andaccordingly chooses one of the additional arguments (in`...` ). |

sys.call, sys.calls, sys.frame, sys.frames, sys.function, sys.nframe, sys.on.exit, sys.parent, sys.parents | Provide access to `environment` s ("frames" in Sterminology) associated with functions farther up the callingstack. |

sys.source | Parses expressions in a given file and thensuccessively evaluates them in the specifiedenvironment. |

sys.status | Provides access to `environment` s ("frames" in Sterminology) associated with functions farther up the callingstack. |

system | Invokes the OS command specified by `command` . |

system.file | Finds the full filenames of files in packages, etc. |

system.time | Returns CPU (and other) times that `expr` used. |

t | Given a matrix or `data.frame` `x` , `t` returns the transpose of `x` . Methods include `t.data.frame` and `t.default` . |

table | Uses the cross-classifying factors to build acontingency table of the counts at each combination of factorlevels. |

tabulate | Takes the integer-valued vector `bin` and counts the number of timeseach integer occurs in it. |

tan | Computes the tangent. |

tanh | Computes the hyperbolic tangent. |

tapply | Applies a function to each cell of a ragged array, i.e., to each (nonempty) group of values given by a uniquecombination of the levels of certain factors. |

taskCallbackManager | Provides an entirely S-language mechanism for managingcallbacks or actions that are invoked at the conclusion ofeach top-level task. Essentially, we register a single Rfunction from this manager with the underlying nativetask-callback mechanism, and this function handles invokingthe other R callbacks under the control of the manager. Themanager consists of a collection of functions that accessshared variables to manage the list of user-levelcallbacks. |

tcrossprod | Given matrices `x` and`y` as arguments, returns amatrix cross-product. This is formally equivalent to (butusually slightly faster than) the call `x \%*\% t(y)` (`tcrossprod` ). |

tempdir, tempfile | `tempfile` returns avector of character strings that can be used as names fortemporary files. |

textConnection, textConnectionValue | Input and output text connections. |

toString | This is a helper function for `format` to produce a single-characterstring describing an R object. |

tolower | Translates characters in character vectors, inparticular, from upper- to lowercase or vice versa. |

topenv | Finds the top-level environment. |

toupper | Translates characters in character vectors, inparticular, from upper-to lower case or vice versa. |

trace | A call to `trace` allows you to insert debugging code (e.g., a call to `browser` or `recover` ) at chosen places in anyfunction. A call to `untrace` cancels the tracing. |

traceback | By default, `traceback()` prints the call stack ofthe last uncaught error, i.e., the sequence of calls that ledto the error. |

tracemem | Marks an object so that a message is printed wheneverthe internal function `duplicate` is called. |

tracingState | Tracing can be temporarily turned on or off globally bycalling `tracingState` . |

transform | Returns a new data frame by applying a set oftransformations to an existing data frame. |

trigamma | Special mathematical functions related to the beta andgamma functions. |

trunc | Takes a single numeric argument `x` and returns a numeric vectorcontaining the integers formed by truncating the values in`x` toward `0` . |

truncate, truncate.connection | Functions to reposition connections. |

try | A wrapper to run an expression that might fail andallow the user's code to handle error recovery. |

tryCatch | Provides a mechanism for handling unusual conditions, including errors and warnings. |

typeof | Determines the (R internal) type of storage mode of anyobject. |

unclass | Returns (a copy of) its argument with its classattribute removed. |

undebug | Sets, unsets, or queries the debugging flag on afunction. |

union | Performs *set* union, intersection, (asymmetric!) difference, equality, and membership on twovectors. |

unique | Returns a vector, data frame, or array like `x` but with duplicate elements/rowsremoved. |

units, units<- | Extracts units from a difftime object. |

unix.time | Returns CPU (and other) times that `expr` used. |

unlink | Deletes the file(s) or directories specified by`x` . |

unlist | Given a list structure `x` , simplifies it to produce a vectorthat contains all the atomic components that occur in `x` . |

unloadNamespace | Function to load and unload namespaces. |

unlockBinding | Unlocks individual bindings in a specifiedenvironment. |

unname | Removes the `names` or`dimnames` attribute of an Robject. |

unserialize | A simple low-level interface for serializing toconnections. |

unsplit | Reverses the effect of `split` . |

untrace | A call to `trace` allows you to insert debugging code (e.g., a call to `browser` or `recover` ) at chosen places in anyfunction. A call to `untrace` cancels the tracing. |

untracemem | Undoes a call to `tracemem` . |

unz | Function to create, open, and closeconnections. |

upper.tri | Returns a matrix of logicals the same size of a givenmatrix with entries `TRUE` inthe lower or upper triangle. |

url | Function to create, open, and closeconnections. |

utf8ToInt | Conversion of UTF-8 encoded character vectors to andfrom integer vectors. |

vector | Produces a vector of a given length and mode. |

warning | Generates a warning message that corresponds to itsargument(s) and (optionally) the expression or function fromwhich it was called. |

warnings | `warnings` and its`print` method print thevariable `last.warning` in apleasing form. |

weekdays | Extracts the weekdays from an object. |

which | Gives the `TRUE` indices of a logical object, allowing for arrayindices. |

which.max, which.min | Determines the location, i.e., index of the (first)minimum or maximum of a numeric vector. |

with | Evaluates an R expression in an environment constructedfrom data, possibly modifying the originaldata. |

withCallingHandlers | Calling handlers are established by `withCallingHandlers` . |

withRestarts | Restarts are used for establishing recovery protocols.They can be established using `withRestarts` . |

withVisible | Evaluates an expression, returning it in a two-elementlist containing its value and a flag showing whether it wouldautomatically print. |

within | Evaluates an R expression in an environment constructedfrom data, possibly modifying the original data. |

write | The data (usually a matrix) `x` is written to file `file` . If the object is atwo-dimensional matrix, you need to transpose it to get thecolumns in `file` the same asthose in the internal representation. |

write.dcf | Reads or writes an R object from/to a file in Debiancontrol file format. |

writeBin | Reads binary data from a connection or writes binarydata to a connection. |

writeChar | Transfers character strings to and from connections, without assuming they are null terminated on theconnection. |

writeLines | Writes text lines to a connection. |

xor | This operator acts on logical vectors. |

xpdrows.data.frame | Auxiliary function for use with data frames. |

xtfrm | A generic auxiliary function that produces a numericvector that will sort in the same order as `x` . |

zapsmall | Determines a `digits` argument `dr` for calling`round(x, digits = dr)` suchthat values close to 0 (compared with the maximal absolutevalue) are "zapped, " i.e., treated as `0` . |

~ | Tilde is used to separate the left- and righthand sidesin model formula. |