is.recursive

R Base 3.6.2

is.atomic returns TRUE if x is of an atomic type (or NULL) and FALSE otherwise. is.recursive returns TRUE if x has a recursive (list-like) structure and FALSE otherwise.

Syntax

is.atomic(x)
is.recursive(x)

Arguments

Parameter	Description
`x`	object to be tested.

Details

is.atomic is true for the atomic types ("logical", "integer", "numeric", "complex", "character" and "raw") and NULL. Most types of objects are regarded as recursive. Exceptions are the atomic types, NULL, symbols (as given by as.name), S4 objects with slots, external pointers, and---rarely visible from R---weak references and byte code, see typeof. It is common to call the atomic types ‘atomic vectors’, but note that is.vector imposes further restrictions: an object can be atomic but not a vector (in that sense). These are primitive functions.

Examples

Example

# NOT RUN {
require(stats)

is.a.r <- function(x) c(is.atomic(x), is.recursive(x))

is.a.r(c(a = 1, b = 3)) # TRUE FALSE
is.a.r(list())          # FALSE TRUE - a list is a list
is.a.r(list(2))         # FALSE TRUE
is.a.r(lm)              # FALSE TRUE
is.a.r(y ~ x)           # FALSE TRUE
is.a.r(expression(x+1)) # FALSE TRUE
is.a.r(quote(exp))      # FALSE FALSE
# }

is.recursive

Syntax

Arguments

Details

Examples

See Also