Age in Years of Individuals

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) (defaults to 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 of reference (either 365 or 366).

na.rm

a logical to indicate whether missing values should be removed

...

arguments passed on to as.POSIXlt(), such as origin

Value

An integer (no decimals) if exact = FALSE, a double (with decimals) otherwise

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  1932-08-03  90  90.21918         67
#> 2  1984-07-10  38  38.28493         15
#> 3  1986-05-06  36  36.46301         13
#> 4  1964-10-20  58  58.00548         35
#> 5  1967-07-23  55  55.24932         32
#> 6  1962-05-31  60  60.39452         37
#> 7  1947-07-30  75  75.23014         52
#> 8  1973-03-03  49  49.63836         26
#> 9  1932-04-29  90  90.48219         67
#> 10 1988-09-07  34  34.12329         11