Hi,
I am trying to understand why creating Date variables does not work if I subset
to avoid NAs.
I had problems creating these Date variables in my code and I thought that the
presence of NAs was the cause. So I used a condition to avoid NAs.
It turns out that NAs are not a problem and I do not need to subset, but I'd
like to understand why subsetting causes the problem.
The strange numbers I start with are what I get when I read an Excel sheet with
the function read.xls() from package gdata.
dat1 = c(41327, 41334, 41341, 41348, 41355, 41362, 41369, 41376, 41383, 41390,
41397)
dat2 = dat1
dat2[c(5,9)]=NA
Data = data.frame(dat1,dat2)
keep1 = !is.na(Data$dat1)
keep2 = !is.na(Data$dat2)
Data$Dat1a = as.Date(Data[,"dat1"], origin="1899-12-30")
Data$Dat1b[keep1] = as.Date(Data[keep1,"dat1"], origin="1899-12-30")
Data$Dat2a = as.Date(Data[,"dat2"], origin="1899-12-30")
Data$Dat2b[keep2] = as.Date(Data[keep2,"dat2"], origin="1899-12-30")
Data
dat1 dat2 Dat1a Dat1b Dat2a Dat2b
1 41327 41327 2013-02-22 15758 2013-02-22 15758
2 41334 41334 2013-03-01 15765 2013-03-01 15765
3 41341 41341 2013-03-08 15772 2013-03-08 15772
4 41348 41348 2013-03-15 15779 2013-03-15 15779
5 41355 NA 2013-03-22 15786 <NA> NA
6 41362 41362 2013-03-29 15793 2013-03-29 15793
7 41369 41369 2013-04-05 15800 2013-04-05 15800
8 41376 41376 2013-04-12 15807 2013-04-12 15807
9 41383 NA 2013-04-19 15814 <NA> NA
10 41390 41390 2013-04-26 15821 2013-04-26 15821
11 41397 41397 2013-05-03 15828 2013-05-03 15828
So variables Dat1b and Dat2b are not converted to Date class.
sessionInfo()
R version 2.15.2 (2012-10-26)
Platform: x86_64-apple-darwin9.8.0/x86_64 (64-bit)
locale:
[1] fr_CA.UTF-8/fr_CA.UTF-8/fr_CA.UTF-8/C/fr_CA.UTF-8/fr_CA.UTF-8
attached base packages:
[1] stats graphics grDevices utils datasets methods base
other attached packages:
[1] gdata_2.12.0
loaded via a namespace (and not attached):
[1] gtools_2.7.0
Thanks in advance,
Denis
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