hasName is a convenient way to test for one or more names
in an R object.
One or more character values to look for.
A logical vector of the same length as name containing
TRUE if the corresponding entry is in names(x).
hasName(x, name) is defined to be equivalent to
name %in% names(x), though it will evaluate slightly more
quickly. It is intended to replace the common idiom
!is.null(x$name). The latter can be unreliable due to partial
name matching; see the example below.