new_vctr: vctr (vector) S3 class
In vctrs: Vector Helpers

new_vctr

R Documentation

vctr (vector) S3 class

Description

This abstract class provides a set of useful default methods that makes it considerably easier to get started with a new S3 vector class. See vignette("s3-vector") to learn how to use it to create your own S3 vector classes.

Usage

new_vctr(.data, ..., class = character(), inherit_base_type = NULL)

Arguments

`.data`	Foundation of class. Must be a vector
`...`	Name-value pairs defining attributes
`class`	Name of subclass.
`inherit_base_type`	A single logical, or `NULL`. Does this class extend the base type of `.data`? i.e. does the resulting object extend the behaviour of the underlying type? Defaults to `FALSE` for all types except lists, which are required to inherit from the base type.

Details

List vctrs are special cases. When created through new_vctr(), the resulting list vctr should always be recognized as a list by obj_is_list(). Because of this, if inherit_base_type is FALSE an error is thrown.

Base methods

The vctr class provides methods for many base generics using a smaller set of generics defined by this package. Generally, you should think carefully before overriding any of the methods that vctrs implements for you as they've been carefully planned to be internally consistent.

[[ and [ use NextMethod() dispatch to the underlying base function, then restore attributes with vec_restore(). rep() and ⁠length<-⁠ work similarly.
⁠[[<-⁠ and ⁠[<-⁠ cast value to same type as x, then call NextMethod().
as.logical(), as.integer(), as.numeric(), as.character(), as.Date() and as.POSIXct() methods call vec_cast(). The as.list() method calls [[ repeatedly, and the as.data.frame() method uses a standard technique to wrap a vector in a data frame.
as.factor(), as.ordered() and as.difftime() are not generic functions in base R, but have been reimplemented as generics in the generics package. vctrs extends these and calls vec_cast(). To inherit this behaviour in a package, import and re-export the generic of interest from generics.
==, !=, unique(), anyDuplicated(), and is.na() use vec_proxy().
<, <=, >=, >, min(), max(), range(), median(), quantile(), and xtfrm() methods use vec_proxy_compare().
+, -, /, *, ^, %%, %/%, !, &, and | operators use vec_arith().
Mathematical operations including the Summary group generics (prod(), sum(), any(), all()), the Math group generics (abs(), sign(), etc), mean(), is.nan(), is.finite(), and is.infinite() use vec_math().
dims(), ⁠dims<-⁠, dimnames(), ⁠dimnames<-⁠, levels(), and ⁠levels<-⁠ methods throw errors.