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
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