Hello,
Try the following.
mat <- data.matrix(read.table(text="
2011 7 21 15 25 20.609
2011 7 21 15 25 23.265
2011 7 21 15 25 26.000
2011 7 21 15 25 28.671
2011 7 21 15 25 31.343"))
secs <- apply(mat, 1, function(x)
ISOdatetime(x[1], x[2], x[3], x[4], x[5], x[6]))
diff(secs)
# convert to date/time if you need them
dates <- as.POSIXlt(secs, origin="1970-01-01")
diff(dates)
Hope this helps,
Rui Barradas
Em 31-07-2012 13:58, Alaios escreveu:
> Dear all,
> I am having a matrix that stores data information in the following format.
>
>> roofPart1$TimeStamps[1:5,]
> [,1] [,2] [,3] [,4] [,5] [,6]
> [1,] 2011 7 21 15 25 20.609
> [2,] 2011 7 21 15 25 23.265
> [3,] 2011 7 21 15 25 26.000
> [4,] 2011 7 21 15 25 28.671
> [5,] 2011 7 21 15 25 31.343
>
>
> I would like to be able to report some simple statistics based on the time
> differences of two entries. For example to check the time consistency (was my
> device measuring at same intervals ?)
>
> I think the easiest would be to convert the matrix above to pure seconds and
> then just substract them
>
>
> so something like that ...
>
> makeSeconds(roofPart1$TimeStamps[1:5,2])-makeSeconds(roofPart1$TimeStamps[1:5,1])
> makeSeconds(roofPart1$TimeStamps[1:5,3])-makeSeconds(roofPart1$TimeStamps[1:5,2])
> makeSeconds(roofPart1$TimeStamps[1:5,4])-makeSeconds(roofPart1$TimeStamps[1:5,3])
>
>
> Do you know which are the functions for that? A) convert time stamps to
> seconds, B) substract the concecutive elements of the seconds matrix
>
>
> I would like to thank you in advance for your help
>
> B.R
> Alex
> [[alternative HTML version deleted]]
>
>
>
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