Units Attribute of a Vector

Sets or retrieves the "units" attribute of an object. For units.default replaces the builtin version, which only works for time series objects. If the variable is also given a label, subsetting (using [.labelled) will retain the "units" attribute. For a Surv object, units first looks for an overall "units" attribute, then it looks for units for the time2 variable then for time1. When setting "units", value is changed to lower case and any "s" at the end is removed.

Usage

units(x, ...)
# Default S3 method
units(x, none='', ...)
# S3 method for class 'Surv'
units(x, none='', ...)
# Default S3 method
units(x) <- value

Arguments

x

any object

...

ignored

value

the units of the object, or ""

none

value to which to set result if no appropriate attribute is found

Value

the units attribute of x, if any; otherwise, the units attribute of the tspar attribute of x if any; otherwise the value none. Handling for Surv objects is different (see above).

See also

label

Examples

require(survival)
fail.time <- c(10,20)
units(fail.time) <- "Day"
describe(fail.time)
#> fail.time [Day] 
#>        n  missing distinct     Info     Mean 
#>        2        0        2        1       15 
#>                   
#> Value       10  20
#> Frequency    1   1
#> Proportion 0.5 0.5
S <- Surv(fail.time)
units(S)
#> [1] "Day"

label(fail.time) <- 'Failure Time'
units(fail.time) <- 'Days'
fail.time
#> Failure Time [Dayss] 
#> [1] 10 20