Thanks Mark,
[EMAIL PROTECTED] wrote:
# MAKE POSIXct OBJECTS FROM CHARACTER STRINGS
temp1 <- as.POSIXct(strptime("2007-02-02","%Y-%m-%d"))
temp2 <- as.POSIXct(strptime("2007-02-01","%Y-%m-%d"))
# TEMP1 AND TEMP2 ARE SORT OF NUMBERS BUT EACH UNIT IS ONE
# SECOND
result <- difftime(temp1,temp2)
# STILL NOT REALLY A NUMBER
print(result)
print(str(result))
# MAKE IT A NUMBER
numberresult <- unclass(result)
attributes(numberresult) <- NULL
print(numberresult)
This does the trick:
endPeriod<-as.POSIXct(strptime("2008-09-30","%Y-%m-%d"))
startPeriod<-as.POSIXct(strptime("2007-10-01","%Y-%m-%d"))
endProject<-as.POSIXct(strptime("2007-12-31","%Y-%m-%d"))
startProject<-as.POSIXct(strptime("2006-12-01","%Y-%m-%d"))
attributes(endPeriod) <- NULL
attributes(startPeriod) <- NULL
attributes(endProject) <- NULL
attributes(startProject) <- NULL
overlappingDays <-
length(intersect(startPeriod:endPeriod,startProject:endProject))/86400
print(overlappingDays)
[1] 91.04168
But as far as I see here, the method is extremely slow (some seconds for
a single case). It solves the problem now, but taking into account that
I must use the method for a quite large database, I think I must look
for anything faster.
Any new idea will be welcome!!!
Cheers,
Ricardo
--
Ricardo RodrÃguez
Your XEN ICT Team
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