R summary 
PS 17 June 2011)

#help

for help on any function type ?function_name
e.g. ?title, ?read.table

# variable assignment and types

example <- c(1,2,3) # assigns a vector containing numbers 1,2,3 to 'example'


# data import and manipulation 

read.table(file, header = FALSE, sep = "", quote = "\"'",
           dec = ".", row.names, col.names,
           as.is = !stringsAsFactors,
           na.strings = "NA", colClasses = NA, nrows = -1,
           skip = 0, check.names = TRUE, fill = !blank.lines.skip,
           strip.white = FALSE, blank.lines.skip = TRUE,
           comment.char = "#",
           allowEscapes = FALSE, flush = FALSE,
           stringsAsFactors = default.stringsAsFactors(),
           fileEncoding = "", encoding = "unknown")
	
	# file: path to file to be imported; use file.choose() to open dialog window to choose file from finder
	# header = TRUE/FALSE : if file has header or not
	# sep = '' : optional; by default any whitespace is used to separate columns; use 'sep' to define which character is used to split (e.g. '\t' for just tabs)
	# fill = TRUE/FALSE : if TRUE then in case the rows have unequal length, blank fields are implicitly added; FALSE by default

table$column : select column from table (default column names are V1, V2, V3, etc; if header is specified colunms have the specified names)

# subset

subset(x, subset, select)
	# x: object to be subsetted
	# subset: logical expression indicating elements or rows to keep
	# select: 
	
#### PACKAGES	
#installing packages from repositories

install.packages('package_name')

# installing packages from source

install.packages('path_to_package.tar.gz', repos=NULL, type="source")

# load package

library('package_name')