tojulian {CTFS} | R Documentation |
These two functions can be used to convert dates to and from julian formats for computations. There are many functions that do this but these are useful for CTFS. The functions rely upon functions found in the R package survival.
tojulian(x, dateform = "%m/%d/%Y", centurycut = 2020) fromjulian(j, dateform = "%m/%d/%Y")
x |
calendate date in the default format “m/d/yyyy”. The year should be specified with the century included, eg. “12/4/1999” |
j |
the number of days since 1/1/1960 |
dateform |
format for calendar date, see strptime for
format information |
centurycut |
years after this date are assumed to be in the 21st century |
These functions are dependent upon the package survival. They
use the functions mdy.date
and date.mmddyyy
.
The results of tojulian
is a number of days, so it is an integer and can be used for
computation.
|
returns an integer, the number of days since 1/1/1960 formatted as d/m/y where d = day, m = 3 letter abreviation for month eg Jan, Feb, Mar..., and y = year. |
|
returns a calendar date in mm/dd/yyyy format |
Rick Condit
depends on the package survival
## Not run: 1. tojulian() x1="3/5/1987" x2="3/5/2001" y1 <- tojulian(x1) y2 <- tojulian(x2) str(y1) str(y2) y2-y1 2. fromjulian() fromjulian(9925) fromjulian(15039) fromjulian(y1+(y2-y1)) ## End(Not run)