Computes attractive axis breaks for date-time data

pretty_dates() identifies which unit of time the sub-intervals should be measured in to provide approximately n breaks, then chooses a "pretty" length for the sub-intervals and sets start and end points that 1) span the entire range of the data, and 2) allow the breaks to occur on important date-times (i.e. on the hour, on the first of the month, etc.)

Usage

pretty_dates(x, n, ...)

Arguments

x

a vector of POSIXct, POSIXlt, Date, or chron date-time objects

n

integer value of the desired number of breaks

...

additional arguments to pass to function

Value

a vector of date-times that can be used as axis tick marks or bin breaks

Examples

x <- seq.Date(as.Date("2009-08-02"), by = "year", length.out = 2)
pretty_dates(x, 12)
#>  [1] "2009-08-01 UTC" "2009-09-01 UTC" "2009-10-01 UTC" "2009-11-01 UTC"
#>  [5] "2009-12-01 UTC" "2010-01-01 UTC" "2010-02-01 UTC" "2010-03-01 UTC"
#>  [9] "2010-04-01 UTC" "2010-05-01 UTC" "2010-06-01 UTC" "2010-07-01 UTC"
#> [13] "2010-08-01 UTC" "2010-09-01 UTC"