Desktop Survival Guide
by Graham Williams
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DATA MINING
Desktop Survival Guide by Graham Williams |
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At times you may need or want to know about the machine on which you
are running. The R .Platform variable will give
information about the system, and can be used, for example,
to conditionally run code depending on which operating system you are
on.
> .Platform
$OS.type
[1] "unix"
$file.sep
[1] "/"
\$dynlib.ext
[1] ".so"
$GUI
[1] "X11"
$endian
[1] "little"
$pkgType
[1] "source"
> if (.Platform$OS.type == "unix") system("ls")
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There are other variables, but .Platform is the
recommended variable to use for programming. The variable
version also lists information about the version of R
you are running.
> version
_
platform i486-pc-linux-gnu
arch i486
os linux-gnu
system i486, linux-gnu
status beta
major 2
minor 2.0
year 2005
month 09
day 28
svn rev 35702
language R
> if (version$os == "linux-gnu") system("ls")
> if (version$os == "mingw32") system("dir")
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For a summary of the current R session the
sessionInfo function is useful:
> sessionInfo()
R version 2.4.1 (2006-12-18)
i486-pc-linux-gnu
locale:
LC_CTYPE=en_AU;LC_NUMERIC=C;LC_TIME=en_AU;LC_COLLATE=en_AU;
LC_MONETARY=en_AU;LC_MESSAGES=en_AU;LC_PAPER=en_AU;LC_NAME=C;
LC_ADDRESS=C;LC_TELEPHONE=C;LC_MEASUREMENT=en_AU;LC_IDENTIFICATION=C
attached base packages:
[1] "stats" "graphics" "grDevices" "utils" "datasets" "methods"
[7] "base"
other attached packages:
ROCR gplots gdata gtools ada rpart
"1.0-1" "2.3.2" "2.3.1" "2.3.0" "2.0-1" "3.1-34"
ellipse rggobi mice nnet MASS Hmisc
"0.3-2" "2.1.4-4" "1.15" "7.2-31" "7.2-31" "3.2-1"
RGtk2 rattle rcompletion
"2.8.7" "2.1.123" "0.0-12"
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Yet another source of system information is Sys.info
which includes machine name and type, operating system name and
version, and username.
> Sys.info()
sysname release
"Linux" "2.6.12-1-686-smp"
version nodename
"#1 SMP Tue Sep 6 15:52:07 UTC 2005" "athene"
machine login
"i686" "gjw"
user
"gjw"
> if (Sys.info()["sysname"] == "Linux") system("ls")
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Information about various limits of the machine (including things like
maximum integer) is obtained from the .Machine variable.
> .Machine \$double.eps [1] 2.220446e-16 $double.neg.eps [1] 1.110223e-16 [...] $integer.max [1] 2147483647 $sizeof.long [1] 4 $sizeof.longlong [1] 8 $sizeof.longdouble [1] 12 $sizeof.pointer [1] 4 |
A call to capabilities will list optional features that
have been compiled into your version of R:
> capabilities()
jpeg png tcltk X11 http/ftp sockets libxml fifo
TRUE TRUE TRUE TRUE TRUE TRUE TRUE TRUE
cledit iconv NLS
TRUE TRUE TRUE
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The options function in R allows numerous
characteristics of the running R session to be tuned. The
options function without arguments returns a list of
options and their values. Use getOption to get a
specific option value, and options itself to set
values. Options that can be set include the prompt string
(prompt and continuation prompt (continue),
the terminal width (width), number of digits to show when
printing (digits, and many more. In this example we list
some of the options then change width, storing its old
value, evaluate some other functions, then restore the original value:
> options()
$OutDec
[1] "."
$X11colortype
[1] "true"
[...]
$verbose
[1] FALSE
$warn
[1] 0
$warnings.length
[1] 1000
$width
[1] 80
> getOption("width")
[1] 80
>ow <- options(width=120)
[...]
> options(ow)
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Other useful functions include:
> R.home() # Location of R installation: /usr/lib/R
> Sys.sleep(5) # Sleep for 5 seconds.
> proc.time() # shows how much time is currently consumed
> Rprof("Rprof.out") # Profile the execution of R expressions
> system.time([...]) # Execute a command and report the time taken
> on.exit([...]) # Execute commands on exit or interruption
> username <- as.vector(Sys.info()["login"])
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