Abbreviations of R Commands Explained: 150+ R Abbreviations

The R programming language includes many abbreviations. Abbreviations exist in function names, argument names, and allowed values for arguments. This post expands on over 150 R abbreviations with the aim of making it easier for users new to R who are trying to memorise R commands.

Context

Abbreviations save time when typing and can make for less cumbersome code. However, abbreviations often make it more difficult to remember a command. This is especially true when the user does not know what the abbreviation stands for.

R has been developed by a group of technical experts with backgrounds in Linux and Unix, mathematics, statistics, and statistical computing. With gaining popularity, R is now being used by people with little to none of this background. Abbreviations which are intuitive to the experts are not necessarily intuitive to this broader audience. The R help system does a reasonable job of explaining the abbreviations in R. However, I thought it would be useful to write a post listing some of the common abbreviations along with the expansion of the abbreviation. Whereas R sometimes errs on the side of assuming expertise, I thought I'd err on the side of assuming naivety. Thus, the table includes many abbreviations which are probably obvious to most readers.

Table of R Commands

R Command	Abbreviation Expanded	Comments	Type
ls	[L]i[S]t objects	common command in Unix-like operating systems	Basics
rm	[R]e[M]ove objects	common command in Unix-like operating systems	Basics
str	[STR]ucture		Basics
unz	[UNZ]ip		Basics
getwd	[GET] [W]orking [D]irectory		Basics
dir	[DIR]ectory		Basics
sprintf	[PRINT] [F]ormatted	S for String of Silently?	Basics
c	[C]ombine values		Basics
regexpr	[REG]ular [EXPR]ession	Why "regular"? See regular sets, regular language	Strings
diag	[DIAG]onal values of a matrix		Basics
col	[COL]umn		Basics
lapply	[APPLY] to each element of a list or vector and return a [L]ist	L is for List	Basics
sapply	[APPLY ]to each element of a list or vector and attempt to [S]implify the returned object to a vector	S is for Simplify	Basics
mapply	[M]ultivariate version of s[APPLY]		Basics
tapply	[T]able [APPLY] function to sets of values as defined by an index		Basics
apply	[APPLY] function to sets of values as defined by an index		Basics
MARGIN = 1 or 2 in apply	rows [1] come before columns [2]	e.g., a 2 x 3 matrix has 2 rows and 3 columns (note: row count is stated first)	Basics
rmvnorm	[R]andom number generator for [M]ulti[V]ariate [NORM]al data		Basics
rle	[R]un [L]ength [E]ncoding		Basics
ftable	[F]ormat [TABLE]		Basics
xtabs	Cross (i.e., [X]) [TAB]ulation	[X] is the symbol of a cross; [X] is sometimes spoken as "by". Cross-tabulating means to cross one variable with another	Basics
xtable	[TABLE] of the object [X]		Basics
formatC	[FORMAT] using [C] style formats	i.e., [C] the programming language	Basics
Sweave	[WEAVE] [S] code in a LaTeX document	The R Programming language is a dialect of S	Basics
cor	[COR]relation		analyses
ancova	[AN]alysis [O]f [COVA]riance		analyses
manova	[M]ultivariate [AN]alysis [O]f [COVA]riance		analyses
aov	[A]nalysis [O]f [V]ariance		analyses
TukeyHSD	[T]ukey's [H]onestly [S]ignificant [D]ifference		analyses
hclust	[H]ierarchical [CLUST]er analysis		analyses
cmdscale	[C]lassical metric [M]ulti[D]imensional [SCAL]ing		analyses
factanal	[FACT]or [ANAL]ysis		analyses
princomp	[PRIN]cipal [COMP]onents analysis		analyses
prcomp	[PR]incipal [COMP]onents analysis		analyses
lme	[L]inear [M]ixed [E]ffects model		analyses
resid	[RESID]uals		models
ranef	[RAN]dom [EF]fects		models
anova	[AN]alysis [O]f [VA]riance		models
fixef	[FIX]ed [EF]ffects		models
vcov	[V]ariance-[COV]ariance matrix		models
logLik	[LOG] [LIK]elihood		models
BIC	[B]ayesian [I]nformation [C]riteria		models
mcmcsamp	[M]arkov [Chain] [Monte] [C]arlo [SAMP]ling		models
eval	[EVAL]uate an R expression		Basics
cat	con[CAT]enate	standard Unix command	Basics
apropos	Search documentation for a purpose or on a topic (i.e., [APROPOS])	Unix command for search documentation;	Basics
read.csv	[READ] a file in [C]omma [S]eperated [V]alues format	i.e., in each row of the data commas separate values for each variable	Basics
read.fwf	[READ] a file in [F]ixed [W]idth [F]ormat		Basics
seq	Generate [SEQ]uence		Basics
rep	[REP]licate values of x	perhaps also [REP]eat	Basics
dim	[DIM]ension of an object	Typically, number of rows and columns in a matrix	Basics
gl	[G]enerate factor [L]evels		Basics
rbind	[BIND] [R]ows together		Basics
cbind	[BIND] [C]olumns together		Basics
is.na	[IS] [N]ot [A]vailable		Basics
nrow	[N]umber of [ROW]s		Basics
ncol	[N]umber of [COL]umns		Basics
attr	[ATTR]ibute		Basics
rev	[REV]erse		Basics
diff	[DIFF]erence between x and a lag of x		Math
prod	[PROD]uct		Math
var	[VAR]iance		Math
sd	[S]tandard [D]eviation		Math
cumsum	[CUM]ulative [SUM]		Math
cumprod	[CUM]ulative [PROD]uct		Math
setdiff	[DIFF]erence between two [SET]s		Math
intersect	[INTERSECT]ion		Math
Re	[RE]al part of a number		Math
Im	[IM]aginary part of a number		Math
Mod	[MOD]ulo opertion	remainder of division of one number by another	Math
t	[T]ranspose of a vector or matrix		Math
substr	Return [SUBSTR]ing		Strings
strsplit	[SPLIT] a [STR]ing vector		Strings
grep	[G]lobal / [R]egular [E]xpression / [P]rint	Etymology based on text editor instructions in programs such as ed	Strings
sub	[SUB]stitute identified pattern found in string		Strings
gsub	[G]lobal [SUB]stitute identified pattern found in string		Strings
pmatch	[P]artial string [MATCH]ing		Strings
nchar	[N]umber of [CHAR]acters in a string		Strings
ps.options	[OPTIONS] for [P]ost-[S]cript		Graphic Devices
win.metafile	[WIN]dows [METAFILE] graphic		Graphic Devices
dev.off	[DEV]ice [OFF]		Graphic Devices
dev.cur	[CUR]rent [DEV]ice		Graphic Devices
dev.set	[SET] the current [DEV]ice		Graphic Devices
hist	[HIST]ogram		base graphics
pie	[PIE] Chart		base graphics
coplot	[CO]nditioning [PLOT]		base graphics
matplot	[PLOT] colums of [MAT]rices		base graphics
assocplot	[ASSOC]iation [PLOT]		base graphics
plot.ts	[PLOT] [T]ime [S]eries		base graphics
qqnorm	[Quantile]-[Q]uantile [P]lot based on normal distribution		base graphics
persp	[PERSP]ective [P]lot		base graphics
xlim	[LIM]it of the [X] axis		base graphics parameter
ylim	[LIM]it of the [Y] axis		base graphics parameter
xlab	[LAB]el for the [X] axis		base graphics parameter
ylab	[LAB]el for the [Y] axis		base graphics parameter
main	[MAIN] title for the plot		base graphics parameter
sub	[SUB] title for the plot		base graphics parameter
mtext	[M]argin [TEXT]		base graphics parameter
abline	[LINE] on plot often of the form y = [A] + [B] x		base graphics parameter
h argument in abline	[H]orizontal line		base graphics parameter
v argument in abline	[V]ertical line		base graphics parameter
par	Graphics [PAR]ameter		base graphics parameter
adj	[ADJ]ust text [J]ustification		base graphics parameter
bg	[B]ack[G]round colour		base graphics parameter
bty	[B]ox [TY]pe		base graphics parameter
cex	[C]haracter [EX]tension or [EX]pansion of plotting objects		base graphics parameter
cex.sub	[C]haracter [EX]tension or [EX]pansion of [SUB]title		base graphics parameter
cex.axis	[C]haracter [EX]tension or [EX]pansion of [AXIS] annotation		base graphics parameter
cex.lab	[C]haracter [EX]tension or [EX]pansion X and Y [LAB]els		base graphics parameter
cex.main	[C]haracter [EX]tension or [EX]pansion of [MAIN] title		base graphics parameter
col	Default plotting [COL]our		base graphics parameter
las	[L]abel of [A]xis [S]tyle		base graphics parameter
lty	[L]ine [TY]pe		base graphics parameter
lwd	[L]ine [W]i[D]th		base graphics parameter
mar	[MAR]gin width		base graphics parameter
mfg	Next [G]raph for [M]atrix of [F]igures		base graphics parameter
mfcol	[M]atrix of [F]igures entered [COL]umn-wise		base graphics parameter
mfrow	[M]atrix of [F]igures entered [ROW]-wise		base graphics parameter
pch	[P]lotting [CH]aracter		base graphics parameter
ps	[P]oint [S]ize of text	Point is a printing measurement	base graphics parameter
pty	[P]lot region [TY]pe		base graphics parameter
tck	Length of [T]i[CK] marks		base graphics parameter
tcl	[T]i[C]k mark length		base graphics parameter
xaxs	[X] [AX]is [S]tyle		base graphics parameter
yaxs	[Y] [AX]is [S]tyle		base graphics parameter
xaxt	[X] [AX]is [T]ype		base graphics parameter
yaxt	[Y] [AX]is [T]ype		base graphics parameter
asp	[ASP]ect ratio		base graphics parameter
xyplot	[X] [Y] [PLOT]	[X] for horizontal axis; [Y] for vertical axis	lattice
bwplot	[B]ox and [W]hisker plot		lattice
qq	[Q]uantile-[Quantile] plot'		lattice
splom	[S]catter[PLO]t [M]atrix		lattice
optim	[OPTIM]isation		analyses
lm	[L]inear [M]odel		analyses
glm	[G]eneralised [L]inear [M]odel		analyses
nls	[N]onlinear [L]east [S]quare parameter esetimation		analyses
loess	[LO]cally [E]stimated [S]catterplot [S]moothing		analyses
prop.test	[TEST] null hypothesis that [PROP]ortions in several gropus are the same		analyses
rnorm	[R]andom number drawn from [NORM]al distribution		distributions
dnorm	[D]ensity of a given quantile in a [NORM]al distribution		distributions
pnorm	[D]istribution function for [NORM]al distribution returning cumulaive [P]robability		distributions
qnorm	[Q]uantile function based on [NORM]al distribution		distributions
rexp	[R]andom number generation from [EXP]onential distribution		distributions
rgamma	[R]andom number generation from [GAMMA] distribution		distributions
rpois	[R]andom number generation from [POIS]on distribution		distributions
rweibull	[R]andom number generation from [WEIBULL] distribution		distributions
rcauchy	[R]andom number generation from [CAUCHY] distribution		distributions
rbeta	[R]andom number generation from [BETA] distribution		distributions
rt	[R]andom number generation from [t] distribution		distributions
rf	[R]andom number generation from [F] distribution	F for Ronald [F]isher	distributions
rchisq	[R]andom number generation from [CHI] [SQ]uare distribution		distributions
rbinom	[R]andom number generation from [BINOM]ial distribution		distributions
rgeom	[R]andom number generation from [EXP]onential distribution		distributions
rhyper	[R]andom number generation from [HYPER]geometric distribution		distributions
rlogis	[R]andom number generation from [LOGIS]tic distribution		distributions
rlnorm	[R]andom number generation from [L]og [NOR]mal distribution		distributions
rnbinom	[R]andom number generation from [N]egative [BINOM]ial distribution		distributions
runif	[R]andom number generation from [UNIF]orm distribution		distributions
rwilcox	[R]andom number generation from [WILCOX]on distribution		distributions
ggplot	[G]rammar of [G]raphics [PLOT]	See Leland Wilkinson (1999)	Graphics
x as argument	[X] is common letter for unknown variable in math		Basics
FUN as argument	[FUN]ction		Basics
pos as argument	[POS]ition		Basics
lib.loc in library	[LIB]rary folder [LOC]ation		Basics
sep as argument	[SEP]erator character		Basics
comment.char in read.table	[COMMENT] [CHAR]acter(s)		Basics
I	[I]nhibit [I]nterpretation		Basics
T value	[T]rue		Basics
F value	[F]alse		Basics
na.rm	[N]ot [A]vailable values are to be [R]e[M]oved		Basics
fivenum	[FIVE] [NUM]ber summary		Basics
IQR	[I]nter [Q]uartile [R]ange		Basics
coef	Model [COEF]ficients		Basics
dist	Compute [DIST]ance matrix		Basics
df	[D]egrees of [F]reedom		Basics
mad	[M]edian [A]bsolute [D]eviation		Basics
sink	Divert R output to a connection (i.e., like connecting a pipe to a [SINK])		Basics
eol in write.table	[End] [O]f [L]ine character(s)		Basics
R	[R]oss Ihaka and [R]obert Gentleman or [R] is letter before S		Basics
CRAN	[C]omprehensive [R] [A]rchive [N]etwork		Basics

Concluding Comments

I thank Tom Short for his R reference Card which provided some inspiration for a starting list of R commands. Feel free to reproduce or adapt this table elsewhere. For example, perhaps it could be included in an R Wiki with additional entries. If you spot an error in the table, let me know in the comments of this post.

I might expand the table in the future. At the moment, it's mainly function names with not many arguments or values of arguments. I also haven't put much time into grouping and ordering the functions.