R: Check for a function argument.

checkArg {BBmisc}

R Documentation

Check for a function argument.

Description

Throws exception if checks are not passed. Note that argument is evaluated when checked.

Usage

checkArg(x, cl, s4 = FALSE, len, min.len, max.len, choices, subset,
  lower = NA, upper = NA, na.ok = TRUE, formals)

Arguments

`x`	[any] Argument.
`cl`	[`character`] Class that argument must “inherit” from. If multiple classes are given, `x` must “inherit” from at least one of these. See also argument `s4`.
`s4`	[`logical(1)`] If `TRUE`, use `is` for checking class `cl`, otherwise use `inherits`, which implies that only S3 classes are correctly checked. This is done for speed reasons as calling `is` is pretty slow. Default is `FALSE`.
`len`	[`integer(1)`] Length that argument must have. Not checked if not passed, which is the default.
`min.len`	[`integer(1)`] Minimal length that argument must have. Not checked if not passed, which is the default.
`max.len`	[`integer(1)`] Maximal length that argument must have. Not checked if not passed, which is the default.
`choices`	[any] Discrete number of choices, expressed by a vector of R objects. If passed, argument must be identical to one of these and nothing else is checked.
`subset`	[any] Discrete number of choices, expressed by a vector of R objects. If passed, argument must be identical to a subset of these and nothing else is checked.
`lower`	[`numeric(1)`] Lower bound for numeric vector arguments. Default is `NA`, which means not required.
`upper`	[`numeric(1)`] Upper bound for numeric vector arguments. Default is `NA`, which means not required.
`na.ok`	[`logical(1)`] Is it ok if a vector argument contains NAs? Default is `TRUE`.
`formals`	[`character`] If this is passed, `x` must be a function. It is then checked that `formals` are the names of the (first) formal arguments in the signature of `x`. Meaning `checkArg(function(a, b), formals="a")` is ok. Default is missing.

Value

Nothing.

Examples

x = 1L
checkArg(x, "integer", len=1, na.ok=FALSE, upper=3L)
x = as.integer(NA)
checkArg(x, "integer", len=1, na.ok=TRUE)
x = c("foo", "bar")
checkArg(x, "character")
x = "foo"
checkArg(x, choices=c("foo", "bar"))
x = c("foo", "bar")
checkArg(x, subset=c("foo", "bar"))
fun = function(foo, bar)
checkArg(fun, formals=c("foo", "bar"))

[Package BBmisc version 1.7 Index]