Dear R People:
I have a data frame with the two following date columns:
> a.df[1:10,c(1,6)]
DATE DEATH
1207 2009-04-16 2009-05-06
1514 2009-04-16 2009-05-06
2548 2009-04-16 2009-05-08
3430 2009-04-16 2009-05-09
3851 2009-04-16 2009-05-09
3945 2009-04-16 2009-05-09
7274 2009-04-16 2009-05-12
7532 2009-04-16 2009-05-12
7651 2009-04-16 2009-05-12
8495 2009-04-16 2009-05-13
>
I would like to generate a 3rd column which is the difference in days
between the two dates.
I tried
a.df$DEATH - a.df$DATE
but I obtain all NA.
Any help would be much appreciated.
Thanks,
Erin
--
Erin Hodgess
Associate Professor
Department of Computer and Mathematical Sciences
University of Houston - Downtown
mailto: erinm.hodg...@gmail.com
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