+,CFtime,numeric-method {CFtime}

Extend a CFtime object with additional offsets

Description

A CFtime instance can be extended by adding additional offsets using this operator.

Usage

## S4 method for signature 'CFtime,numeric'
e1 + e2

Arguments

e1

CFtime. Instance of the CFtime class.

e2

numeric. Vector of offsets to be added to the CFtime instance.

Details

The resulting CFtime instance will have its offsets in the order that they are added, meaning that the offsets from the CFtime instance come first and those from the numeric vector follow. 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 two is thus preserved, if and only if the data sets are merged in the same order.

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 datum.

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

Negative offsets will generate an error.

Any bounds that were set will be removed. Use bounds() to retrieve the bounds of the individual CFtime instances and then set them again after merging the two instances.

Value

A CFtime object with offsets composed of the CFtime instance and the numeric vector.

Examples

e1 <- CFtime("days since 1850-01-01", "gregorian", 0:364)
e2 <- 365:729
e1 + e2