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Extend a CFTime or CFClimatology object

Source: R/api.R
plus-.CFTime.Rd

A CFTime or CFClimatology instance can be extended with this operator, using values from another CFTime or CFClimatology instance, respectively, or a vector of numeric offsets or character timestamps. If the values come from another CFTime or CFClimatology instance, the calendars of the two instances must be compatible. If the calendars of the instances are not compatible, an error is thrown.

Usage

# S3 method for class 'CFTime'
e1 + e2

# S3 method for class 'CFClimatology'
c1 + c2

Arguments

e1

Instance of the CFTime class.

e2

Instance of the CFTime class with a calendar compatible with that of argument e1. This argument may also be a numeric vector with offsets from the origin of argument e1, or a vector of character timestamps in ISO8601 or UDUNITS format.

c1, c2

Instances of the CFClimatology class, having compatible calendars.

Value

A CFTime object with the offsets of argument e1 extended by the values from argument e2.

A CFClimatology object with the offsets of argument c1 extended by the values from argument c2.

Details

The resulting CFTime or CFClimatology instance will have the offsets of the original instance, appended with offsets from argument e2 in the order that they are specified. If the new sequence of offsets is not monotonically increasing a warning is generated (the COARDS metadata convention requires offsets to be monotonically increasing).

There is no reordering or removal of duplicates. This is because the time series are usually associated with a data set and the correspondence between the data in the files and the instance is thus preserved. When merging the data sets described by this time series, the order must be identical to the merging here.

Note that when adding multiple vectors of offsets to a CFTime instance, it is more efficient to first concatenate the vectors and then do a final addition to the CFTime instance. So avoid CFtime(definition, calendar, e1) + CFtime(definition, calendar, e2) + CFtime(definition, calendar, e3) + ... but rather do CFtime(definition, calendar) + c(e1, e2, e3, ...). It is the responsibility of the operator to ensure that the offsets of the different data sets are in reference to the same calendar.

Note also that RNetCDF and ncdf4 packages both return the values of the "time" dimension as a 1-dimensional array. You have to de-class the array to a vector before adding offsets to an existing CFtime instance.

If both operands to this operator are CFTime or CFClimatology instances and both have bounds set, then their bounds will be preserved in the result.

Examples

e1 <- CFTime$new("days since 1850-01-01", "gregorian", 0:364)
e2 <- CFTime$new("days since 1850-01-01 00:00:00", "standard", 365:729)
e1 + e2
#> CF calendar:
#>   Origin  : 1850-01-01T00:00:00
#>   Units   : days
#>   Type    : standard
#> 
#> Time series:
#>   Elements: [1850-01-01 .. 1851-12-31] (average of 1.000000 days between 730 elements)
#>   Bounds  : not set