type_sum() gives a brief summary of object type. Objects that commonly
occur in a data frame should return a string with four or less characters.
For most inputs, the argument is forwarded to vctrs::vec_ptype_abbr().
obj_sum() also includes the size (but not the shape) of the object
if vctrs::vec_is() is TRUE.
It should always return a string (a character vector of length one).
As of pillar v1.6.1, the default method forwards to vctrs::vec_ptype_abbr()
for vectors and to type_sum() for other objects.
Previous versions always forwarded to type_sum().
An attribute named "short" in the return value will be picked up by
the pillar_shaft() method for lists, and used if space is limited.
size_sum() is called by obj_sum() to format the size of the object.
It should always return a string (a character vector of length one),
it can be an empty string "" to omit size information,
this is what the default method does for scalars.
Arguments
- x
an object to summarise. Generally only methods of atomic vectors and variants have been implemented.
Details
When formatting a pillar,
type_sum() will be called on a slice of the column vector.
The formatted type should only depend on the type and not on the data,
to avoid confusion.
Examples
obj_sum(1:10)
#> [1] "int [10]"
#> attr(,"short")
#> [1] "int"
obj_sum(matrix(1:10))
#> [1] "int [10 × 1]"
#> attr(,"short")
#> [1] "int[…]"
obj_sum(data.frame(a = 1))
#> [1] "df [1 × 1]"
#> attr(,"short")
#> [1] "df"
obj_sum(Sys.Date())
#> [1] "date [1]"
#> attr(,"short")
#> [1] "date"
obj_sum(Sys.time())
#> [1] "dttm [1]"
#> attr(,"short")
#> [1] "dttm"
obj_sum(mean)
#> [1] "fn"
size_sum(1:10)
#> [1] "[10]"
size_sum(trees)
#> [1] "[31 × 3]"
size_sum(Titanic)
#> [1] "[4 × 2 × 2 × 2]"