zoo_aggregate function

Aggregate Cases in Zoo Time Series

zoo_aggregate(x = NULL, new_time = NULL, f = mean, ...)

Arguments

• x: (required, zoo object) Time series to aggregate. Default: NULL

• new_time: (optional, zoo object, keyword, or time vector) New time to aggregate x to. The available options are:

  • NULL: the highest resolution keyword returned by zoo_time(x)$keywords is used to generate a new time vector to aggregate x.
  • zoo object: the index of the given zoo object is used as template to aggregate x.
  • time vector: a vector with new times to resample x to. If time in x is of class "numeric", this vector must be numeric as well. Otherwise, vectors of classes "Date" and "POSIXct" can be used indistinctly.
  • keyword: a valid keyword returned by zoo_time(x)$keywords, used to generate a time vector with the relevant units.
  • numeric of length 1: interpreted as new time interval, in the highest resolution units returned by zoo_time(x)$units.

• f: (optional, quoted or unquoted function name) Name of a standard or custom function to aggregate numeric vectors. Typical examples are mean, max,min, median, and quantile. Default: mean.

• ...: (optional, additional arguments) additional arguments to f.

Returns

zoo object

Examples

#full range of calendar dates
x <- zoo_simulate(
  rows = 1000,
  time_range = c(
    "0000-01-01",
    as.character(Sys.Date())
    )
)

#plot time series
if(interactive()){
  zoo_plot(x)
}

#find valid aggregation keywords
x_time <- zoo_time(x)
x_time$keywords

#mean value by millennia (extreme case!!!)
x_millennia <- zoo_aggregate(
  x = x,
  new_time = "millennia",
  f = mean
)

if(interactive()){
  zoo_plot(x_millennia)
}

#max value by centuries
x_centuries <- zoo_aggregate(
  x = x,
  new_time = "centuries",
  f = max
)

if(interactive()){
  zoo_plot(x_centuries)
}

#quantile 0.75 value by centuries
x_centuries <- zoo_aggregate(
  x = x,
  new_time = "centuries",
  f = stats::quantile,
  probs = 0.75 #argument of stats::quantile()
)

if(interactive()){
  zoo_plot(x_centuries)
}

See Also

Other zoo_functions: zoo_name_clean(), zoo_name_get(), zoo_name_set(), zoo_permute(), zoo_plot(), zoo_resample(), zoo_smooth_exponential(), zoo_smooth_window(), zoo_time(), zoo_to_tsl(), zoo_vector_to_matrix()