Skip to contents

Validate a Count

Source: R/checks.R
checkCount.Rd

Checks that an argument is a single finite integer, not smaller than min. Meant for the many size arguments in the suite - digits, sep, width, nPerm, R and the like - which are conceptually counts rather than numbers and were previously spelled out by hand wherever they occur.

Usage

checkCount(x, min = 0L, name = deparse(substitute(x)))

Arguments

x

the value to check.

min

the smallest admissible value, 0 by default. Pass 1 for the arguments that must be positive, e.g. a width or a number of replicates.

name

the argument name to use in the message. Defaults to the expression that was passed.

Value

x, invisibly.

Details

A whole number stored as a double is accepted, as that is what arithmetic on integers produces and what a user typing 2 supplies. TRUE is not, although it would survive as.integer(): a flag that reaches a count argument is a mistake, not a shorthand for one.

The order of the tests is the same as in checkConfLevel(), length first, then type, then value, so that the message names the argument rather than the condition that failed.

See also

checkConfLevel(), checkFlag(), checkString()

Examples

sep <- 2
checkCount(sep)

width <- 80
checkCount(width, min = 1)

if (FALSE) { # \dontrun{
checkCount(1.5)                # not a whole number
checkCount(-1)                 # below the default minimum
checkCount(TRUE)               # a flag is not a count
} # }