tbl_time
objects have a time index that contains information about
which column should be used for time-based subsetting and other time-based
manipulation. Otherwise, they function as normal tibbles.
as_tbl_time(x, index = NULL, ...)
tbl_time(x, index = NULL)
An object to be converted to tbl_time
. This is generally
a tibble::tibble()
, or an object that can first be coerced to a tibble
.
The bare column name of the column to be used as the index.
Arguments passed to tibble::as_tibble()
if coercion is
necessary first.
The information stored about tbl_time
objects are the index_quo
and the
index_time_zone
. These are stored as attributes, with the index_quo
as a
rlang::quosure()
and the time_zone
as a string.
Currently, Date
and POSIXct
classes are fully supported. yearmon
,
yearqtr
, and hms
have experimental support. Due to dplyr's
handling of S3 classes like these 3, the classes are lost when you
manipulate the index columns directly.
# Converting a data.frame to a `tbl_time`
# Using Date index
ex1 <- data.frame(date = Sys.Date(), value = 1)
ex1_tbl_time <- as_tbl_time(ex1, date)
class(ex1_tbl_time)
#> [1] "tbl_time" "tbl_df" "tbl" "data.frame"
attributes(ex1_tbl_time)
#> $class
#> [1] "tbl_time" "tbl_df" "tbl" "data.frame"
#>
#> $row.names
#> [1] 1
#>
#> $names
#> [1] "date" "value"
#>
#> $index_quo
#> <quosure>
#> expr: ^date
#> env: 0x5621cbae4e08
#>
#> $index_time_zone
#> [1] "UTC"
#>
# Converting a tibble to a `tbl_time`
# Using POSIXct index
ex2 <- tibble::tibble(
time = as.POSIXct(c("2017-01-01 10:12:01", "2017-01-02 12:12:01")),
value = c(1, 2)
)
as_tbl_time(ex2, time)
#> # A time tibble: 2 × 2
#> # Index: time
#> time value
#> <dttm> <dbl>
#> 1 2017-01-01 10:12:01 1
#> 2 2017-01-02 12:12:01 2