monkeyshines monkeyshines - 4 months ago 15
R Question

change a column from birth date to age in r

I am using data.table for the first time.

I have a column of about 400,000 ages in my table. I need to convert them from birth dates to ages.

What is the best way to do this?

Answer

From the comments of this blog entry, I found the age_calc function in the eeptools package. It takes care of edge cases (leap years, etc.), checks inputs and looks quite robust.

library(eeptools)
x <- as.Date(c("2011-01-01", "1996-02-29"))
age_calc(x[1],x[2]) # default is age in months

[1] 46.73333 224.83118

age_calc(x[1],x[2], units = "years") # but you can set it to years

[1] 3.893151 18.731507

floor(age_calc(x[1],x[2], units = "years"))

[1] 3 18

For your data

yourdata$age <- floor(age_calc(yourdata$birthdate, units = "years"))

assuming you want age in integer years.