R Syntax Overview (modified from that of Barry W. Brown).

I.  EXPRESSIONS (expr is an expression of your choice)
	 A.   Literals
	      number		       1  1.1  1.1e10
	      string		       'string' or "string"
	      comment		       # string.
	      function (formals) expr  function(args){defn}

	 B.   Calls
	      expr infix expr
	      expr %anything% expr
	      unary expr
	      expr ( arglist )
	      expr [ arglist ]
	      expr [[ arglist ]]
	      expr $ fname

	 C.   Assignment
	      expr <- expr
	      expr -> expr
	      expr = expr

	 D.   Conditional
	      if ( expr ) expr
	      if ( expr ) expr else expr

	 E.   Iteration
	      while ( expr  ) expr
	      for ( Name in expr ) expr     

II.  ARITHMETIC OPERATORS
	 *    Multiply
	 +    Add
	 -    Subtract
	 /    Divide
	 ^    Exponentiation
	 %%   Remainder or modulo operator
	 %*%  Matrix multiplication operator
	 %/%  Integer divide
	 %c%  crossproduct	       
	 %o%  Outer Product

III.  RELATIONAL OPERATORS
	 !=   Not-equal-to
	 <    Less-than
	 <=   Less-than-or-equal-to
	 ==   Equal
	 >    Greater-than
	 >=   Greater-than-or-equal-to

IV.  LOGICAL OPERATORS
	 !    Not
	 |    Or (Use with arrays or matrices)
	 ||   Shortcut Or (Don't use with arrays or matrices)
	 &    And (Use with arrays or matrices)
	 &&   Shortcut And (Don't use with arrays or matrices)

V.  SUBSCIPTS
	 [ ]	Vector subscript
	 [[ ]]  list subscript - can only identify a single element
	 $	Named component selection from a list

VI.  SEQUENCE AND REPETITION 
	seq (from, to, by, length, along)
		also    :     as in 1:10
	rep(x, times, length)       

VII.  ARTIHMETIC OPERATORS AND FUNCTIONS
	abs(x)
	acos(x)
	acosh(x)
	asin(x)
	asinh(x)
	atan(x)
	atan(x, y)
	atanh(x)
	ceiling(x)
	cos(x)
	cosh(x)
	exp(x)
	floor(x)
	gamma(x)
	lgamma(x)
	log(x, base=exp(1))
	log10(x)
	max(...)		       elementwise
	min(...)		       elementwise
	pmax(...)		       parallel 
	pmin(...)		       parallel
	sin(x)
	sinh(x)
	sqrt(x)
	tan(x)
	tanh(x)
	trunc(x)

VIII.  TYPES
	Can be used in as.<type> and is.<type> and <type>(length=n calls.
	      array
	      category		       is, as only
	      character
	      complex
	      double
	      integer
	      list
	      logical
	      matrix
	      null		       is, as only
	      numeric

IX.  IN AND OUT OF S

	 A.   Data In
	      scan(file="", what=numeric(), n, sep)
	      read.table(file="")

	 B.   Command File In
	      source(file, local = F)

	 C.   Screen Output to File
	      sink(file)
	      sink( )		       restores output to screen
	 
	 E.   Make Things (Including Help) Available or Unavailable
	      assign("name", value, frame, where)
	      attach(file, pos=2)
	      detach(what=2)
	      library( )
	      help(name="help")
	      args(name="help")

X.  REDUCTION OPERATORS
	all(...)
	any(...)
	length(x)
	max(...)
	mean(x, trim=0)
	median(x)
	min(...)
	mode(x)
	prod(...)
	quantile(x, probs=c(0,.25,.5,.75,1))
	sum(...)
	var(x,y)
	cor(x,y,trim=0)

XI.  STATISTICAL DISTRIBUTIONS
	d<dist>(x,<parameters>)		  density at x
	p<dist>(x,<parameters>)		  cumulative distn fn to x
	q<dist>(p,<parameters>)		  inverse cdf
	r<dist>(n,<parameters>)		  generates n random numbers from distn   

     	+--------------------------------------------------------------+
     	|  <dist>       Distribution       Parameters        Defaults  |
     	+--------------------------------------------------------------+
     	|  beta         beta             shape1, shape2        -, -    |
     	|  cauchy       Cauchy           loc, scale            0, 1    |
     	|  chisq        chi-square       df                    -       |
     	|  exp          exponential      -                     -       |
     	|  f            F                df1, df2              -, -    |
     	|  gamma        Gamma            shape                 -       |
     	|  lnorm        log-normal       mean, sd (of log)     0, 1    |
     	|  logis        logistic         loc, scale            0, 1    |
     	|  norm         normal           mean, sd              0, 1    |
     	|  stab         stable           index, skew           -, 0    |
     	|  t            Student's t      df                    -       |
     	|  unif         uniform          min, max              0, 1    |
     	+--------------------------------------------------------------+

XII.  PLOTTING
	A. postscript(file, command, horizontal=F, width,
	      height, rasters, pointsize=14, font=1,
	      preamble=ps.preamble, fonts=ps.fonts)

	B. pdf((file = ifelse(onefile, "Rplots.pdf", "Rplot%03d.pdf"), 
    		width = 6, height = 6, onefile = TRUE, ...) 
	
	C. Some Plot Parameters
	      main='title'
	      new=<logical>	       T forces addition to current plot
              lty=n                    Line type
              pch='.'                  Plot character
	      xlab='x-axis label'
	      ylab='y-axis label'
	      xlim=c(xlo.value,xhi.value)
	      ylim=c(ylo.value,yhi.value)

	 D.   One-Dimension Plots
	      barplot(height)     #simple form
	      barplot(height, width, names, space=.2, inside=TRUE,
	      		beside=FALSE, horiz=FALSE, legend, angle,
	      		density, col, blocks=TRUE)
	      boxplot(..., range, width, varwidth=FALSE,
	      		notch=FALSE, names, plot=TRUE)
	      hist(x, nclass, breaks, plot=TRUE, angle,
	      		density, col, inside)

	 E.   Two-Dimension Plots
	      lines(x, y, type="l")
	      points(x, y, type="p"))
	      abline(coef) abline(a, b) abline(reg) abline(h=) abline(v=)
	      qqplot(x, y, plot=TRUE)
	      qqnorm(x, datax=FALSE, plot=TRUE)

	 F.   Three-Dimension Plots
	      contour(x, y, z, v, nint=5, add=FALSE, labex)
	      persp(z, eye=c(-6,-8,5), ar=1)

XIII. WRITING FUNCTIONS
	 A. 	tr <- function(in.mat) sum(diag(in.mat))

	 B. 	plot.box <- function(x1,y1,x2,y2)  {
        		segments(x1,y1,x1,y2)
        		segments(x1,y2,x2,y2)
        		segments(x2,y2,x2,y1)
        		segments(x2,y1,x1,y1)
		}

	 C.   Returning can be done with a final declaration or the return() 	
	      statement.

	 D.   Note that functions can (and should) call other functions.