calculating number of days between 2 columns of dates in data frame

Question

I have a data frame which has two columns of dates in the format yyyy/mm/dd. I am trying to calculate the number of days between these two dates for each observation within

Answer 1

You need to use the as.Date formats correctly.

Eg.

x = '2012/07/25'
xd = as.Date(x,'%Y/%m/%d')
xd    # Prints "2012-07-25"

R date formats are similary to *nix ones.

Doing a typeof(xd) shows it as a double ie. days since 1970.