Displaying 2 results from an estimated 2 matches for "datecent".
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datacent
2012 Sep 18
2
Data frame divison by another data frame with common groups and different length
Dear all,
I have two different data frames, that have two common variables: date and
sample. Here is a small extract of both of them
> head(traffic)
datet sessiont samplet buddleiat
1 07-08-2012 1 1 1
2 07-08-2012 1 1 1
3 07-08-2012 1 1 1
4 07-08-2012 1 2 3
5 07-08-2012 1 2
2005 Jul 28
4
CSV file and date. Dates are read as factors!
I am using read.csv to read a CSV file (produced by saving an Excel file
as a CSV file). The columns containing dates are being read as factors.
Because of this, I can not compute follow-up time, i.e.
Followup<-postDate-preDate. I would appreciate any suggestion that would
help me read the dates as dates and thus allow me to calculate follow-up
time.
Thanks
John
John Sorkin M.D., Ph.D.
Chief,