Character string with advanced substitutions

Package: R.utils
Class GString

character
~~|
~~+--GString

Directly known subclasses:

public static class GString
extends character

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:

	`as.character`	-
	`evaluate`	-
	`gcat`	-
	`getBuiltinDate`	-
	`getBuiltinDatetime`	-
	`getBuiltinHostname`	-
	`getBuiltinOs`	-
	`getBuiltinPid`	-
	`getBuiltinRhome`	-
	`getBuiltinRversion`	-
	`getBuiltinTime`	-
	`getBuiltinUsername`	-
	`getRaw`	-
	`getVariableValue`	-
	`gstring`	-
	`parse`	-
	`print`	-

Methods inherited from character:
Ops,nonStructure,vector-method, Ops,structure,vector-method, Ops,vector,nonStructure-method, Ops,vector,structure-method, all.equal, as.Date, as.POSIXlt, as.data.frame, as.raster, coerce,ANY,character-method, coerce,character,SuperClassMethod-method, coerce,character,signature-method, coerce<-,ObjectsWithPackage,character-method, coerce<-,signature,character-method, downloadFile, formula, getDLLRegisteredRoutines, glyphJust, isOpen, makeRaw, sha1, toAsciiRegExprPattern, toFileListTree, toLatex, uses

Author

Henrik Bengtsson

Examples

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

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

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

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


# - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
# Looping over vectors
# - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
x <- 1:5
y <- c("hello", "world")
cat(as.character(GString("(x,y)=(${x},${y})")), sep=", ")
#> (x,y)=(1,hello), (x,y)=(2,world), (x,y)=(3,hello), (x,y)=(4,world), (x,y)=(5,hello)
cat("\n")
#> 

cat(as.character(GString("(x,y)=(${x},$[capitalize]{y})")), sep=", ")
#> (x,y)=(1,Hello), (x,y)=(2,World), (x,y)=(3,Hello), (x,y)=(4,World), (x,y)=(5,Hello)
cat("\n")
#> 


# - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
# 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}.")))
#> Hello henrik on host hb-x1-2023 running R v4.3.2 in process #143673 on unix. R is installed in /home/henrik/shared/software/CBI/_ubuntu22_04/R-4.3.2-gcc11/lib/R.


# Other built-in variables/functions...
cat(as.character(GString("Current date: ${date}\n")))
#> Current date: 2023-11-17
cat(as.character(GString("Current date: $[format='%d/%m/%y']{date}\n")))
#> Current date: $[format='%d/%m/%y']{date}
cat(as.character(GString("Current time: ${time}\n")))
#> Current time: 17:03:28


# - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
# Evaluating inline R code
# - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
cat(as.character(GString("Simple calculation: 1+1=${`1+1`}\n")))
#> Simple calculation: 1+1=2
cat(as.character(GString("Alternative current date: ${`date()`}\n")))
#> Alternative current date: Fri Nov 17 17:03:28 2023


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


# - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
# Global search-replace feature
# - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
# Replace all '-' with '.'
cat(as.character(GString("Current date: ${date/-/.}\n")))
#> Current date: 2023.11.17
# Another example
cat(as.character(GString("Escaped string: 12*12=${`12*12`/1/}\n")))
#> Escaped string: 12*12=44


# - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
# 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}\n")))
#> A letter: NA
cat(as.character(GString("Another letter: ${aletter}\n")))
#> Another letter: NA


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

cat(as.character(GString("Advanced example: ${gstring}\n")))
#> Error in if (any(nchar(value) > 0L)) break: missing value where TRUE/FALSE needed


# 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: ${runif}\n")))
#> Error in if (any(nchar(value) > 0L)) break: missing value where TRUE/FALSE needed
n <- 5
cat(as.character(GString("${n} random numbers: ")))
#> 5 random numbers: 
cat(as.character(GString("$[n=n, format='f']{runif}")))
#> $[n=n, format='f']{runif}
cat("\n")
#> 


# 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: ")))
#> $Random number of numbers: 
cat(as.character(GString("$[n=runif(n=1,min=1,max=5), format='f']{runif}")))
#> $[n=runif(n=1,min=1,max=5), format='f']{runif}
cat("\n")
#>

Character string with advanced substitutions

Arguments

Fields and Methods

Author

See also

Examples