try this, and you will get a clue:
> (today <- Sys.Date())
[1] "2007-08-17"
> class(today)
[1] "Date"
> as.Date("2007-08-17") == today
[1] TRUE
so basically,
your.target = as.Date("1979-12-14")
apply(A, c(1,2), function(x) x==your.target)) # should work. I did not
test though.
HTH,
Weiwei
On 8/17/07, Gonçalo Ferraz <[EMAIL PROTECTED]> wrote:
> Hi,
>
> If I have a data frame A with the following format:
>
> Day1 Day2 Day3 Day4
> 1 1979-11-02 1979-11-03 1979-11-04 <NA>
> 2 1979-12-06 <NA> <NA> <NA>
> 3 1979-12-13 1979-12-14 1979-12-15 1979-12-16
> 4 1979-12-20 <NA> <NA> <NA>
>
> And a date "1979-12-14", for example.
>
> How can I find the row or rows of the data frame were that date can be
> found?
>
> The date is stored in a date format variable called 'day'. I am trying
> commands such as A==day, expecting to see a matrix of logical values, but I
> am only getting error messages such as "(list) object cannot be coerced to
> 'double'".
>
> I am looking for a simple command that would return, in this case, a vector:
>
> FALSE FALSE TRUE FALSE
>
> Thanks for any help!
>
> Gonçalo
>
> [[alternative HTML version deleted]]
>
>
> ______________________________________________
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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.
>
>
--
Weiwei Shi, Ph.D
Research Scientist
GeneGO, Inc.
"Did you always know?"
"No, I did not. But I believed..."
---Matrix III
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