Message-ID: <201205081951.q48JpKR7008960@hypatia.math.ethz.ch>
Date: 2012-05-08T19:50:47Z
From: Jeff
Subject: Lowest year among several variables
In-Reply-To: <1336474932.90764.YahooMailNeo@web161606.mail.bf1.yahoo.com >
...still new to R and trying to figure this one out.
I have a number of variables x, y, z, etc. in a data frame.
Each contains a 2 digit year (e.g., 80, 81, 82) representing the
first year that something occurred. Each variable represents a
different type of event.
If the event did not occur at all, the variable has the value 0 (zero).
I need to create a new variable having the value of the earliest year
among the set of variables.
If none of the events occurred (all variables = 0), then the new
variable should also be zero.
e.g.,
Original
x y z
80 82 83
85 76 90
90 0 86
0 0 0
New variable
80
76
86
0