egsub

From R.utils v1.32.4 by Henrik Bengtsson

Global substitute of expression using regular expressions

Global substitute of expression using regular expressions.

Keywords: utilities, programming

Usage

egsub(pattern, replacement, x, ..., value=TRUE, envir=parent.frame(), inherits=TRUE)

Arguments

pattern: A character string with the regular expression to be matched, cf. gsub().
replacement: A character string of the replacement to use when there is a match, cf. gsub().
x: The expression or a function to be modified.
...: Additional arguments passed to gsub()
value: If TRUE, the value of the replacement itself is used to look up a variable with that name and then using that variables value as the replacement. Otherwise the replacement value is used.
envir, inherits: An environment from where to find the variable and whether the search should also include enclosing frames, cf. get(). Only use if v

Value

Returns an expression.

Examples

# Original expression
expr <- substitute({
  res <- foo.bar.yaa(2)
  print(res)
  R.utils::use("R.oo")
  x <- .b.
})

# Some predefined objects
foo.bar.yaa <- function(x) str(x)
a <- 2
b <- a

# Substitute with variable name
expr2 <- egsub("^[.]([a-zA-Z0-9_.]+)[.]$", "\\1", expr, value=FALSE)
print(expr2)
## {
##     res <- foo.bar.yaa(2)
##     print(res)
##     R.utils::use("R.oo")
##     x <- b
## }

# Substitute with variable value
expr3 <- egsub("^[.]([a-zA-Z0-9_.]+)[.]$", "\\1", expr, value=TRUE)
print(expr3)
## {
##     res <- foo.bar.yaa(2)
##     print(res)
##     R.utils::use("R.oo")
##     x <- 2
## }

# Substitute the body of a function
warnifnot <- egsub("stop", "warning", stopifnot, value=FALSE)
print(warnifnot)
warnifnot(pi == 3.14)

Documentation reproduced from package R.utils, version 1.32.4, License: LGPL (>= 2.1)

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