How to convert a numeric value into a Date value

Question

So, I have a data.frame with a column called Date.birth, but I have these values in a numeric format:

Date.birth
43067
43060

Probably is problem format. But I need in a Date format like these:

Date.birth
11/28/17
11/21/17

Actually the above format is the correct. I tried this command:

as.Date(levels(data$Date.birth), format="%d.%m.%Y")

but didn't work. Anyone has a suggestion?

Thanks.

Answer 1

We need to specify the origin if it is a numeric value

as.Date(data$Date.birth, origin = "1899-12-30")

e.g.

as.Date(43067, origin = "1899-12-30")
#[1] "2017-11-28"

After converting to Date class, if it needs to be in a custom format, use format

format(as.Date(43067, origin = "1899-12-30"), "%m/%d/%y")
#[1] "11/28/17"

If your column is factor, do convert to numeric first

as.Date(as.numeric(as.character(data$Date.birth)), origin = "1899-12-30")

Answer 2

If this is an excel numeric date, janitor has a great solution:

library(janitor)

excel_numeric_to_date(data$Date.birth)

Answer 3

It can be simply done by using lubridate package-

lubridate::as_date(as.numeric(dt$Date.birth),origin="1899-12-30")  
[1] "2017-11-28" "2017-11-21"

Sample Data-

dt <- read.table(text="Date.birth
43067
43060",header=T)