On 10/16/2011 04:13 AM, Alaios wrote:
Dear all
I have the following time stamps (in the following format)

MeasurementSet$TimeStamps
        [,1] [,2] [,3] [,4] [,5]   [,6]
   [1,] 2011    7    2   13   43 48.718
   [2,] 2011    7    2   13   43 54.281
   [3,] 2011    7    2   13   43 59.843
   [4,] 2011    7    2   13   44  5.390
   [5,] 2011    7    2   13   44 10.859
   [6,] 2011    7    2   13   44 16.375
   [7,] 2011    7    2   13   44 21.890
   [8,] 2011    7    2   13   44 27.390
   [9,] 2011    7    2   13   44 33.015
  [10,] 2011    7    2   13   44 38.531
  [11,] 2011    7    2   13   44 44.078
  [12,] 2011    7    2   13   44 49.546
  [13,] 2011    7    2   13   44 55.078
  [14,] 2011    7    2   13   45  0.718
  [15,] 2011    7    2   13   45  6.281
  [16,] 2011    7    2   13   45 11.953
  [17,] 2011    7    2   13   45 17.453
  [18,] 2011    7    2   13   45 22.984


I would like to write a function that will have inputs like that:
         function(data, TimeStamps, timeBegin, timeEnd) {(not fixed though)


and will return the index of start and the end.

I need your help specify how the input arguments should look like  (something 
simple and compatible with the format I have already should be good).
Then based on that two arguments, how I can search for start and end of 
timestamps inside the MeasurementSet$Timestamps and return the indexes of start 
and end of the time block?

Hi Alex,
I think what you are trying to do is this:

TimeStamps<-matrix(
 c(2011,7,2,13,43,48.718,
  2011,7,2,13,43,54.281,
  2011,7,2,13,43,59.843,
  2011,7,2,13,44,5.390,
  2011,7,2,13,44,10.859,
  2011,7,2,13,44,16.375,
  2011,7,2,13,44,21.890,
  2011,7,2,13,44,27.390,
  2011,7,2,13,44,33.015,
  2011,7,2,13,44,38.531,
  2011,7,2,13,44,44.078,
  2011,7,2,13,44,49.546,
  2011,7,2,13,44,55.078,
  2011,7,2,13,45,0.718,
  2011,7,2,13,45,6.281,
  2011,7,2,13,45,11.953,
  2011,7,2,13,45,17.453,
  2011,7,2,13,45,22.984),
 ncol=6,byrow=TRUE)

findBeginEnd<-function(x,timeBegin,timeEnd) {
 bits2date<-function(x) {
  the_date<-strptime(paste(x,c("-","-"," ",":",":",""),
   sep="",collapse=""),format="%Y-%m-%d %H:%M:%S")
  return(the_date)
 }
 dimx<-dim(x)
 timeBegin<-strptime(timeBegin,format="%Y-%m-%d %H:%M:%S")
 timeEnd<-strptime(timeEnd,format="%Y-%m-%d %H:%M:%S")
 start_index<-1
 nextdate<-bits2date(x[1,])
 while(nextdate < timeBegin && start_index < dimx[1]) {
  start_index<-start_index + 1
  nextdate<-bits2date(x[start_index,])
 }
 end_index<-start_index
 while(timeEnd > nextdate && end_index < dimx[1]) {
  end_index<-end_index + 1
  nextdate<-bits2date(x[end_index,])
 }
 return(list(start=start_index,end=end_index))
}

findBeginEnd(TimeStamps,"2011-7-2 13:44:20.0","2011-7-2 13:45:12.0")

Jim

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