tsibble (version 0.7.0)

tsibble-package: tsibble: tidy temporal data frames and tools

Description

The tsibble package provides a data class of tbl_ts to represent tidy temporal data. A tsibble consists of a time index, key, and other measured variables in a data-centric format, which is built on top of the tibble.

Index

The time indices are preserved as the essential data component of the tsibble, instead of implicit attribute (for example, the tsp attribute in a ts object). A few index classes, such as Date, POSIXct, and difftime, forms the basis of the tsibble, with new additions yearweek, yearmonth, and yearquarter representing year-week, year-month, and year-quarter respectively. Any arbitrary index class are also supported, including zoo::yearmon, zoo::yearqtr, and nanotime. For a tbl_ts of regular interval, a choice of index representation has to be made. For example, a monthly data should correspond to time index created by yearmonth or zoo::yearmon, instead of Date or POSIXct. Because months in a year ensures the regularity, 12 months every year. However, if using Date, a month contains days ranging from 28 to 31 days, which results in irregular time space. This is also applicable to year-week and year-quarter.

Since the tibble that underlies the tsibble only accepts a 1d atomic vector or a list, a tbl_ts doesn't accept POSIXlt and timeDate columns.

Key

Key variable(s) together with the index uniquely identifies each record, which can be created via the id function as identifiers:

• Empty: an implicit variable id() resulting in a univariate time series.

• One or more variables: explicit variables. For example, data(pedestrian) and data(tourism) use the id(Sensor) & id(Region, State, Purpose) as the key respectively.

Interval

The interval function returns the interval associated with the tsibble.

• Regular: the value and its time unit including "nanosecond", "microsecond", "millisecond", "second", "minute", "hour", "day", "week", "month", "quarter", "year". An unrecognisable time interval is labelled as "unit".

• Irregular: as_tsibble(regular = FALSE) gives the irregular tsibble. It is marked with !.

• Unknown: if there is only one entry for each key variable, the interval cannot be determined (?).

An interval is obtained based on the corresponding index representation:

• integer/numeric: either "unit" or "year"

• yearquarter/yearqtr: "quarter"

• yearmonth/yearmon: "month"

• yearweek: "week"

• Date: "day"

• POSIXct: "hour", "minute", "second", "millisecond", "microsecond"

• nanotime: "nanosecond"

Time zone

Time zone corresponding to index will be displayed if index is POSIXct. ? means that the obtained time zone is a zero-length character "".

Print options

The tsibble package fully utilises the print method from the tibble. Please refer to tibble::tibble-package to change display options.

See Also

Useful links:

• https://tsibble.tidyverts.org

• Report bugs at https://github.com/tidyverts/tsibble/issues

Examples

# NOT RUN {
# create a tsibble w/o a key ----
tsibble(
  date = as.Date("2017-01-01") + 0:9,
  value = rnorm(10)
)

# create a tsibble with one key ----
tsibble(
  qtr = rep(yearquarter("2010-01") + 0:9, 3),
  group = rep(c("x", "y", "z"), each = 10),
  value = rnorm(30),
  key = id(group)
)
# }