Re: [R] first occurrence of a value?

From: Patrick Breheny <patrick.breheny_at_uky.edu>
Date: Wed, 04 May 2011 08:17:25 -0400

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?
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>
> [[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.



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. Received on Thu 05 May 2011 - 06:25:12 GMT

Archive maintained by Robert King, hosted by the discipline of statistics at the University of Newcastle, Australia.
Archive generated by hypermail 2.2.0, at Thu 05 May 2011 - 07:00:07 GMT.

Mailing list information is available at https://stat.ethz.ch/mailman/listinfo/r-help. Please read the posting guide before posting to the list.

list of date sections of archive