Calculates age in years based on a reference date, which is the system date at default.
Usage
age(x, reference = Sys.Date(), exact = FALSE, na.rm = FALSE, ...)
Arguments
- x
date(s), character (vectors) will be coerced with
as.POSIXlt()
- reference
reference date(s) (default is today), character (vectors) will be coerced with
as.POSIXlt()
- exact
a logical to indicate whether age calculation should be exact, i.e. with decimals. It divides the number of days of year-to-date (YTD) of
x
by the number of days in the year ofreference
(either 365 or 366).- na.rm
a logical to indicate whether missing values should be removed
- ...
arguments passed on to
as.POSIXlt()
, such asorigin
Details
Ages below 0 will be returned as NA
with a warning. Ages above 120 will only give a warning.
This function vectorises over both x
and reference
, meaning that either can have a length of 1 while the other argument has a larger length.
See also
To split ages into groups, use the age_groups()
function.
Examples
# 10 random pre-Y2K birth dates
df <- data.frame(birth_date = as.Date("2000-01-01") - runif(10) * 25000)
# add ages
df$age <- age(df$birth_date)
# add exact ages
df$age_exact <- age(df$birth_date, exact = TRUE)
# add age at millenium switch
df$age_at_y2k <- age(df$birth_date, "2000-01-01")
df
#> birth_date age age_exact age_at_y2k
#> 1 1956-04-16 67 67.23836 43
#> 2 1987-11-01 35 35.69315 12
#> 3 1985-12-13 37 37.57808 14
#> 4 1982-10-28 40 40.70411 17
#> 5 1986-11-14 36 36.65753 13
#> 6 1945-03-15 78 78.32603 54
#> 7 1941-09-14 81 81.82466 58
#> 8 1970-02-09 53 53.41918 29
#> 9 1932-01-25 91 91.46027 67
#> 10 1964-02-08 59 59.42192 35