Usually when we type par() on console it will give a list of all default parameters of par function. But what about plot, when I try plot() it gives an error. What is different about functions such as this.
Does it have something to do with it being generic function. Please point to any resource I can read up on this.
Example, using args() and formalArgs() or formals() function to know the list of arguments in a function.
I. Using args()
args(qplot)
# function (x, y = NULL, ..., data, facets = NULL, margins = FALSE,
# geom = "auto", xlim = c(NA, NA), ylim = c(NA, NA), log = "",
# main = NULL, xlab = deparse(substitute(x)), ylab = deparse(substitute(y)),
# asp = NA, stat = NULL, position = NULL)
# NULL
II. Using formalArgs()
formalArgs(qplot)
# [1] "x" "y" "..." "data" "facets" "margins" "geom" "xlim" "ylim" "log"
# [11] "main" "xlab" "ylab" "asp" "stat" "position"
III. Using formals()
formals(qplot)
# $x
# $y
NULL
# $...
# $data
# $facets
# NULL
# $margins
# [1] FALSE
# $geom
# [1] "auto"
# $xlim
# c(NA, NA)
# $ylim
# c(NA, NA)
# $log
# [1] ""
# $main
# NULL
# $xlab
# deparse(substitute(x))
# $ylab
# deparse(substitute(y))
# $asp
# [1] NA
# $stat
# NULL
# $position
# NULL
Then to check, type ?qplot in R Console and check in the help page whether it has the same arguments.
IV. Analysis on par() and some other similar kind of functions like options()
class(par)
# [1] "function"
class(par())
# [1] "list"
class(plot)
# [1] "function"
class(plot())
# Error in xy.coords(x, y, xlabel, ylabel, log) :
# argument "x" is missing, with no default
names(par())
# [1] "xlog" "ylog" "adj" "ann" "ask" "bg" "bty" "cex" "cex.axis"
# [10] "cex.lab" "cex.main" "cex.sub" "cin" "col" "col.axis" "col.lab" "col.main" "col.sub"
# [19] "cra" "crt" "csi" "cxy" "din" "err" "family" "fg" "fig"
# [28] "fin" "font" "font.axis" "font.lab" "font.main" "font.sub" "lab" "las" "lend"
# [37] "lheight" "ljoin" "lmitre" "lty" "lwd" "mai" "mar" "mex" "mfcol"
# [46] "mfg" "mfrow" "mgp" "mkh" "new" "oma" "omd" "omi" "page"
# [55] "pch" "pin" "plt" "ps" "pty" "smo" "srt" "tck" "tcl"
# [64] "usr" "xaxp" "xaxs" "xaxt" "xpd" "yaxp" "yaxs" "yaxt" "ylbias"
par() is a functions which has list of parameters, whichever parameter you specify those will be stored inside par() and in turn will effect the plot, the rest parameter has its own default set.
Similar kind of function options()
class(options)
# [1] "function"
class(options())
# [1] "list"
head(names(options())) # List is bigger, just printing head of it
# [1] "add.smooth" "browserNLdisabled" "CBoundsCheck" "check.bounds" "citation.bibtex.max"
# [6] "continue"
Calling options() like par()
options()
$add.smooth
# [1] TRUE
# $browserNLdisabled
# [1] FALSE
# $CBoundsCheck
# [1] FALSE
# $check.bounds
# [1] FALSE
# $citation.bibtex.max
# [1] 1
# $continue
# [1] "+ "
# $contrasts
# unordered ordered
# "contr.treatment" "contr.poly"
# $defaultPackages
# [1] "datasets" "utils" "grDevices" "graphics" "stats" "methods"
# $demo.ask
# [1] "default"
# $deparse.cutoff
# [1] 60
# $device
# function (width, height, pointsize, record, rescale, xpinch,
# ypinch, bg, canvas, gamma, xpos, ypos, buffered, title, restoreConsole,
# clickToConfirm, fillOddEven, family = "", antialias)
# {
# check <- Sys.getenv("_R_CHECK_SCREEN_DEVICE_", "")
# msg <- "screen devices should not be used in examples etc"
# if (identical(check, "stop"))
# stop(msg, domain = NA)
# else if (identical(check, "warn"))
# warning(msg, immediate. = TRUE, noBreaks. = TRUE, domain = NA)
# new <- list()
# if (!missing(width))
# new$width <- as.double(width)
# if (!missing(height))
# new$height <- as.double(height)
# if (!missing(pointsize))
# new$pointsize <- as.double(pointsize)
# if (!missing(record))
# new$record <- record
# if (!missing(rescale))
# new$rescale <- rescale
# if (!missing(xpinch))
# new$xpinch <- as.double(xpinch)
# if (!missing(ypinch))
# new$ypinch <- as.double(ypinch)
# if (!missing(bg))
# new$bg <- bg
# if (!missing(canvas))
# new$canvas <- canvas
# if (!missing(gamma))
# new$gamma <- gamma
# if (!missing(xpos))
# new$xpos <- as.integer(xpos)
# if (!missing(ypos))
# new$ypos <- as.integer(ypos)
# if (!missing(buffered))
# new$buffered <- buffered
# if (!missing(title))
# new$title <- title
# if (!missing(restoreConsole))
# new$restoreConsole <- restoreConsole
# if (!missing(clickToConfirm))
# new$clickToConfirm <- clickToConfirm
# if (!missing(fillOddEven))
# new$fillOddEven <- fillOddEven
# if (!missing(antialias))
# new$antialias <- match.arg(antialias, aa.win)
# d <- check.options(new = new, envir = .WindowsEnv, name.opt = ".Windows.Options",
# reset = FALSE, assign.opt = FALSE)
# rescale <- match(d$rescale, c("R", "fit", "fixed"))
# if (is.na(rescale))
# stop("invalid value for 'rescale'")
# antialias <- pmatch(d$antialias, aa.win)
# invisible(.External(C_devga, "", d$width, d$height, d$pointsize,
# d$record, rescale, d$xpinch, d$ypinch, d$canvas, d$gamma,
# d$xpos, d$ypos, d$buffered, .PSenv, d$bg, d$restoreConsole,
# d$title, d$clickToConfirm, d$fillOddEven, family, antialias))
# }
# <bytecode: 0x0000000015330530>
# <environment: namespace:grDevices>
# $device.ask.default
# [1] FALSE
# $digits
# [1] 7
# $echo
# [1] TRUE
# $editor
# [1] "internal"
# $encoding
# [1] "native.enc"
# $example.ask
# [1] "default"
# $expressions
# [1] 5000
# $help.search.types
# [1] "vignette" "demo" "help"
# $help.try.all.packages
# [1] FALSE
# $help_type
# [1] "html"
# $HTTPUserAgent
# [1] "R (3.3.0 x86_64-w64-mingw32 x86_64 mingw32)"
# $install.packages.compile.from.source
# [1] "interactive"
# $internet.info
# [1] 2
# $keep.source
# [1] TRUE
# $keep.source.pkgs
# [1] FALSE
# $lme4.summary.cor.max
# [1] 12
# $locatorBell
# [1] TRUE
# $mailer
# [1] "mailto"
# $max.print
# [1] 99999
# $menu.graphics
# [1] TRUE
# $mgcv.vc.logrange
# [1] 25
# $na.action
# [1] "na.omit"
# $nwarnings
# [1] 50
# $OutDec
# [1] "."
# $pager
# [1] "internal"
# $papersize
# [1] "letter"
# $pdfviewer
# [1] "C:/PROGRA~1/R/R-33~1.0/bin/x64/open.exe"
# $pkgType
# [1] "both"
# $prompt
# [1] "> "
# $repos
# CRAN CRANextra
# "https://mirrors.tuna.tsinghua.edu.cn/CRAN" "http://www.stats.ox.ac.uk/pub/RWin"
# $scipen
# [1] 0
# $show.coef.Pvalues
# [1] TRUE
# $show.error.messages
# [1] TRUE
# $show.signif.stars
# [1] TRUE
# $str
# $str$strict.width
# [1] "no"
# $str$digits.d
# [1] 3
# $str$vec.len
# [1] 4
# $str.dendrogram.last
# [1] "`"
# $stringsAsFactors
# [1] TRUE
# $timeout
# [1] 60
# $ts.eps
# [1] 1e-05
# $ts.S.compat
# [1] FALSE
# $unzip
# [1] "internal"
# $useFancyQuotes
# [1] TRUE
# $verbose
# [1] FALSE
# $warn
# [1] 0
# $warning.length
# [1] 1000
# $width
# [1] 130
# $windowsTimeouts
# [1] 100 500
