R.utils (version 1.9.7)

GString: Character string with advanced substitutions

Description

Package: R.utils Class GString character ~~| ~~+--GString Directly known subclasses: public static class GString extends character

Usage

GString(..., sep="")

Arguments

...

one or more objects, to be coerced to character vectors.

sep

A character string to separate the terms.

Fields and Methods

Methods: rll{ as.character Gets the processed character string. getBuiltinDate Gets the current date. getBuiltinDatetime Gets the current date and time. getBuiltinHostname Gets the hostname of the system running R. getBuiltinOs Gets the operating system of the running machine. getBuiltinPid Gets the process id of the current R session. getBuiltinRhome Gets the path where R is installed. getBuiltinRversion Gets the current R version. getBuiltinTime Gets the current time. getBuiltinUsername Gets the username of the user running R. getRaw Gets the unprocessed GString. getVariableValue Gets a variable value given a name and attributes. parse Parses a GString. print Prints the processed GString. } Methods inherited from character: all.equal, as.data.frame, as.Date, as.POSIXlt, as.raster, downloadFile, formula, getDLLRegisteredRoutines, isOpen, toAsciiRegExprPattern, toFileListTree, uses

Examples

# - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
# First example
# - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
who <- "world"

# Compare this...
cat(as.character(GString("Hello ${who}
")))

# ...to this.
cat(GString("Hello ${who}
"))

# Escaping
cat(as.character(GString("Hello \\${who}
")))


# - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
# Looping over vectors
# - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
x <- 1:5
y <- c("hello", "world")
cat(as.character(GString("(x,y)=(${x},${y})")), sep=", ")
cat("")

cat(as.character(GString("(x,y)=(${x},$[capitalize]{y})")), sep=", ")
cat("")


# - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
# Predefined ("builtin") variables
# - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
cat(as.character(GString("Hello ${username} on host ${hostname} running R v${rversion} in process #${pid} on ${os}. R is installed in ${rhome}.")))


# Other built-in variables/functions...
cat(as.character(GString("Current date: ${date}
")))
cat(as.character(GString("Current date: $[format='%d/%m/%y']{date}
")))
cat(as.character(GString("Current time: ${time}
")))


# - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
# Evaluating inline R code
# - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
cat(as.character(GString("Simple calculation: 1+1=${`1+1`}
")))
cat(as.character(GString("Alternative current date: ${`date()`}
")))


# - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
# Function values
# - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
# Call function rnorm with arguments n=1, i.e. rnorm(n=1)
cat(as.character(GString("Random normal number: $[n=1]{rnorm}
")))


# - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
# Global search-replace feature
# - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
# Replace all '-' with '.'
cat(as.character(GString("Current date: ${date/-/.}
")))
# Another example
cat(as.character(GString("Escaped string: 12*12=${`12*12`/1/}
")))


# - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
# Defining new "builtin" function values
# - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
# Define your own builtin variables (functions)
setMethodS3("getBuiltinAletter", "GString", function(object, ...) {
  base::letters[runif(1, min=1, max=length(base::letters))]
})

cat(as.character(GString("A letter: ${aletter}
")))
cat(as.character(GString("Another letter: ${aletter}
")))


# Another example
setMethodS3("getBuiltinGstring", "GString", function(object, ...) {
  # Return another GString.
  GString("${date} ${time}")
})

cat(as.character(GString("Advanced example: ${gstring}
")))


# Advanced example
setMethodS3("getBuiltinRunif", "GString", function(object, n=1, min=0, max=1, ...) {
  formatC(runif(n=n, min=min, max=max), ...)
})

cat(as.character(GString("A random number: ${runif}
")))
n <- 5
cat(as.character(GString("${n} random numbers: ")))
cat(as.character(GString("$[n=n, format='f']{runif}")))
cat("")


# Advanced options.
# Options are parsed as if they are elements in a list, e.g.
#   list(n=runif(n=1,min=1,max=5), format='f')
cat(as.character(GString("$Random number of numbers: ")))
cat(as.character(GString("$[n=runif(n=1,min=1,max=5), format='f']{runif}")))
cat("")