globalsByName {globals} | R Documentation |
Locates and retrieves a set of global variables by their names
Description
Locates and retrieves a set of global variables by their names
Usage
globalsByName(names, envir = parent.frame(), mustExist = TRUE, ...)
Arguments
names |
A character vector of global variable names. |
envir |
The environment from where to search for globals. |
mustExist |
If TRUE, an error is thrown if the object of the identified global cannot be located. Otherwise, the global is not returned. |
... |
Not used. |
Value
A Globals object of named elements and an attribute
where
with named elements. Both of sets have names according to
names
.
Special "argument" globals
If names
specifies "..."
, "..1"
, "..2"
, ..., then they
are interpreted as arguments ...
, ..1
, ..2
, ..., respectively.
If specified, then the corresponding elements in the results are
lists of class DotDotDotList
comprising the value of the latter.
If the special argument does not exist, then the value is NA
, and
the corresponding where
attributes is NULL
.
Examples
f <- function(x = 42, ...) {
globalsByName("x")
}
globals <- f()
str(globals)
globals <- f(3.14)
str(globals)
g <- function(x = 42, ...) {
globalsByName("...")
}
globals <- g()
str(globals)
globals <- g(3.14)
str(globals)
globals <- g(3.14, 1L, b = 2L, c = 3L)
str(globals)
h <- function(x = 42, ...) {
globalsByName("..2")
}
globals <- h(x = 3.14, a = 1, b = 2)
str(globals)
globals <- g(3.14)
str(globals)
globals <- g(3.14, 1L, b = 2L, c = 3L)
str(globals)