collectArgs-and-iterateWithArgs: collectArgs and iterateWithArgs

Description Usage Arguments Details Value Examples

Description

Functions to cleanly collect arguments from within one function or environment (to then pass to another or to iterate over)

Usage

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collectArgs(except = c(), incl.dots = TRUE, all.names = TRUE,
  envir = parent.frame())

iterateWithArgs(arg_to_iterate_over, FUNC,
  nm.arg_to_iterate_over = as.character(substitute(arg_to_iterate_over)),
  except = c(), incl.dots = TRUE, envir = parent.frame())

Arguments

except

A vector of string values. Objects to NOT include in the collection Generally, the user will not want to pass objets created inside the function and hence will pass to except _NOTE_ pass the quoted string-name of the object, not the object itself.

incl.dots

A single logical value. Should the ... be collected as well? NOTE: Has no effect in functions without dots argument Default is TRUE.

all.names

A single logical value. Passed to ls(). When FALSE, then objects whose name begins with a '.' are omitted from the collection

envir

An environment object. Passed to ls(). The environment from which to collect the objects. Defaults to parent.frame

arg_to_iterate_over

Object, not the string-name of the object.

FUNC

function or string of length 1. function to iterate over. Normally the same function in which iterateWithArgs is being called

nm.arg_to_iterate_over

The string-name of the object.

Default is as.character(substitute(arg_to_iterate_over))

Details

collectArgs() colects objects from an envrionment into a single list. Generally, the list will then be passed to other functions (usually with do.call)

iterateWithArgs() similarly collects the objects in an environment, with the difference that one specific object is selected to iterate over. For each iteration, the given value is passed along with all the other objects to FUNC.

Value

for collectArgs: A list of all of the objects in envir (less any objects excluded via the parameters). The names of the list are the names of object in envir.

for iterateWithArgs: A list of the return values of FUNC, the length of arg_to_iterate_over. Naming of the list will be handled by do.call

Examples

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sample_function <- function(x, base, thresh=500, verbose=TRUE) {

  some_object    <- is.na(x) ## an example of an object that we will exclude
  another_object <- 1:10     ## an example of an object that we will exclude

  if (length(x) > 1) {
    return(iterateWithArgs(x, FUNC=sample_function, except=c("some_object", "another_object")))
  }

  ret <- (base ^ x)

  if (verbose)
    cat(base, "^", x, " is ", ifelse(ret > thresh, "", "NOT "), "larger than ", thresh, "\n")

  return(ret)
}

sample_function(5, base=2)
sample_function(5:10, base=2)


 some_function <- function(x, param1, param2, etc, ...) {

   ARGS <- collectArgs(except="x")
   return(
           lapply(x, function(x_i) 
              do.call(some_function, c(ARGS, x=x_i))
           )
         )
 }

rsaporta/collectArgs documentation built on Oct. 1, 2018, 1:41 a.m.