reviser represents real-time vintages as tibbles that carry an additional
class recording which dimension indexes the vintages. Data indexed by
publication date are of class tbl_pubdate, data indexed by release number
are of class tbl_release, and both inherit from the common parent class
tbl_vintage, ahead of the usual tibble classes. A fitted class attribute
therefore reads c("tbl_pubdate", "tbl_vintage", "tbl_df", "tbl", "data.frame"). An object that carries both a pub_date and a release
column is classed as both, with tbl_release taking precedence.
The parent class holds everything the two representations share. The
print(), summary(), plot() and pillar::tbl_sum() methods are
defined once for tbl_vintage and inherited by both, so that the two stay
consistent with one another. Only the parts that genuinely depend on the
indexing dimension are dispatched on the child classes, through the
internal generics vintage_labels(), vintage_value_cols() and
vintage_detail().
Both representations may be stored in either a long or a wide layout, and
the methods below detect which and report accordingly. The layouts, and the
columns each one requires, are specified under "Data contract" in
validate_vintages(), which also checks an object against them. Use
vintages_long() and vintages_wide() to convert between layouts.
Value
This topic documents a class rather than a function. The functions
that build vintages data, such as get_nth_release(), vintages_long()
and vintages_wide(), return tibbles whose class attribute is
c("tbl_pubdate", "tbl_vintage", "tbl_df", "tbl", "data.frame") or the
same with "tbl_release" in place of "tbl_pubdate".
Examples
df <- dplyr::filter(reviser::gdp, id == "US")
# Release vintages carry the shared parent class.
releases <- get_nth_release(df, n = 0:3)
class(releases)
#> [1] "tbl_release" "tbl_pubdate" "tbl_vintage" "tbl_df" "tbl"
#> [6] "data.frame"
inherits(releases, "tbl_vintage")
#> [1] TRUE
# So do publication-date vintages, in either layout.
class(vintages_wide(df)$US)
#> [1] "tbl_pubdate" "tbl_vintage" "tbl_df" "tbl" "data.frame"
# The print, summary and plot methods are inherited from the parent.
summary(releases)
#>
#> === Vintages Data Summary (Release Format) ===
#>
#> Format: long
#> Time periods: 179
#> Time range: 1980-01-01 to 2024-07-01
#> Number of IDs: 1
#> IDs: US
#>
#> Number of releases: 4
#> Releases: release_0, release_1, release_2, release_3
#>
#> Missing values: 0 of 710 (0%)