first occurrence of a value?

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another approach is:

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))

years <- as.numeric(gsub("^[^0-9]+", "", names(df)))
ind <- apply(sapply(df, "==", 1), 1, function (x) which(x)[1])
df$year <- years[ind]

I hope it helps.

Best,
Dimitris
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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______________________________________________
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PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.

Dimitris Rizopoulos
Assistant Professor
Department of Biostatistics
Erasmus University Medical Center

Address: PO Box 2040, 3000 CA Rotterdam, the Netherlands
Tel: +31/(0)10/7043478
Fax: +31/(0)10/7043014
Web: http://www.erasmusmc.nl/biostatistiek/
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
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?
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

	[[alternative HTML version deleted]]

______________________________________________
R-help at r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
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