Hi:
 
I do not understand the returned value of NA in the following, which is a simplified version of
my attempt to convert the start column of the data frame AirQual in the SwissAir package.
 
as.POSIXct(paste('04.04.2004 0',0:3,sep=''),format='%d.%m.%Y %H')
[1] "2004-04-04 00:00:00 EST" "2004-04-04 01:00:00 EST"
[3] NA                        "2004-04-04 03:00:00 EDT"
 
My sessionInfo() is
 
 sessionInfo()
R version 2.7.0 (2008-04-22)
i386-pc-mingw32
locale:
LC_COLLATE=English_United States.1252;LC_CTYPE=English_United States.1252;LC_MONETARY=English_United States.1252;LC_NUMERIC=C;LC_TIME=English_United States.1252
attached base packages:
[1] stats     graphics  grDevices utils     datasets  methods
[7] base
 
Thank you,
 
Norm

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