You may want to look into the function 'match', which finds the first
occurrence of a value. In your example,
df <- data.frame(j1999=c(0,0,0,0,1,0), j2000=c(NA, 1, 1, 1, 0, 0),
j2001=c(1, 0,
1, 0, 0, 0), year=c(2001, 2000, 2000, 2000, 1999, NA))
apply(df,1,match,x=1)
[1] 3 2 2 2 1 NA
_______________________
Patrick Breheny
Assistant Professor
Department of Biostatistics
Department of Statistics
University of Kentucky
On 05/04/2011 07:52 AM, Albert-Jan Roskam wrote:
Hello,
A simple question perhaps, but how do I, within each row, find the first
occurence of the number 1 in the df below? I want to use this position to
programmatically create the variable 'year'. I'v come up with a solution, but I
find it downright ugly. Is there a simpler way? I was hoping for a useful
built-in function that I don;t yet know about.
df<- data.frame(j1999=c(0,0,0,0,1,0), j2000=c(NA, 1, 1, 1, 0, 0), j2001=c(1, 0,
1, 0, 0, 0), year=c(2001, 2000, 2000, 2000, 1999, NA))
library(gsubfn)
x<- apply(df==1, 1, which)
giveYear<- function(df) { return( as.numeric(gsubfn("^[^0-9]+", "",
names(df)[1])) ) }
df$year2<- sapply(x, giveYear)
Thanks in advance!
Cheers!!
Albert-Jan
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
All right, but apart from the sanitation, the medicine, education, wine, public
order, irrigation, roads, a fresh water system, and public health, what have the
Romans ever done for us?
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