Paul Sorenson Paul.Sorenson at vision-bio.com writes:
:
: I have a frame which contains 3 columns:
:
: date defectnum state
:
: And I want to get the most recent state change for a given defect number.
date is POSIXct.
:
: I have tried:
: aggregate(ev$date, by=list(ev$defectnum), max)
I have a frame which contains 3 columns:
date defectnum state
And I want to get the most recent state change for a given defect number. date
is POSIXct.
I have tried:
aggregate(ev$date, by=list(ev$defectnum), max)
Which appears to be working except that the dates seem to come back as
. If it matters,
find the right answer or convince yourself that this code works.
-Original Message-
From: Paul Sorenson [mailto:[EMAIL PROTECTED]
Sent: Monday, 31 January 2005 1:17 PM
To: r-help@stat.math.ethz.ch
Subject: [R] aggregating dates
I have a frame which contains 3 columns
