assertive.base (version 0.0-9)

use_first: Only use the first element of a vector

Description

If the input is not scalar, then only the first element is returned, with a warning.

Usage

use_first(x, indexer = c("[[", "["), .xname = get_name_in_parent(x))

Arguments

x

Input that should be scalar.

indexer

Either double indexing, "[[" (the default) or single indexing "[".

.xname

Not intended to be used directly.

Value

If x is scalar, it is returned unchanged, otherwise only the first element is returned, with a warning.

Examples

# NOT RUN {
dont_stop(use_first(1:5))
# }