R: Is object a node or pairlist?

is_pairlist {rlang} | R Documentation

## Is object a node or pairlist?

### Description

- `is_pairlist()` checks that `x` has type `pairlist`.

- `is_node()` checks that `x` has type `pairlist` or `language`. It tests whether `x` is a node that has a CAR and a CDR, including callable nodes (language objects).

- `is_node_list()` checks that `x` has type `pairlist` or `NULL`. `NULL` is the empty node list.

### Usage

    is_pairlist(x)

    is_node(x)

    is_node_list(x)

### Arguments

`x` | Object to test.

### Life cycle

These functions are experimental. We are still figuring out a good naming convention to refer to the different lisp-like lists in R.

### See Also

`is_call()` tests for language nodes.

[Package rlang version 0.4.7 Index]