| do.call | R Documentation |
do.call constructs and executes a function call from a name ora function and a list of arguments to be passed to it.
do.call(what, args, quote = FALSE, envir = parent.frame())
what | either a function or a non-empty character string naming thefunction to be called. |
args | alist of arguments to the function call. The |
quote | a logical value indicating whether to quote thearguments. |
envir | an environment within which to evaluate the call. Thiswill be most useful if |
Ifquote isFALSE, the default, then the arguments areevaluated (in the calling environment, not inenvir). Ifquote isTRUE then each argument is quoted (seequote) so that the effect of argument evaluation is toremove the quotes – leaving the original arguments unevaluated when thecall is constructed.
The behavior of some functions, such assubstitute,will not be the same for functions evaluated usingdo.call asif they were evaluated from the interpreter. The precise semanticsare currently undefined and subject to change.
The result of the (evaluated) function call.
This should not be used to attempt to evade restrictions on the use of.Internal and other non-API calls.
Becker, R. A., Chambers, J. M. and Wilks, A. R. (1988)The New S Language.Wadsworth & Brooks/Cole.
call which creates an unevaluated call.
do.call("complex", list(imaginary = 1:3))## if we already have a list (e.g., a data frame)## we need c() to add further argumentstmp <- expand.grid(letters[1:2], 1:3, c("+", "-"))do.call("paste", c(tmp, sep = ""))do.call(paste, list(as.name("A"), as.name("B")), quote = TRUE)## examples of where objects will be found.A <- 2f <- function(x) print(x^2)env <- new.env()assign("A", 10, envir = env)assign("f", f, envir = env)f <- function(x) print(x)f(A) # 2do.call("f", list(A)) # 2do.call("f", list(A), envir = env) # 4do.call( f, list(A), envir = env) # 2do.call("f", list(quote(A)), envir = env) # 100do.call( f, list(quote(A)), envir = env) # 10do.call("f", list(as.name("A")), envir = env) # 100eval(call("f", A)) # 2eval(call("f", quote(A))) # 2eval(call("f", A), envir = env) # 4eval(call("f", quote(A)), envir = env) # 100Add the following code to your website.
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