Question about time series
Hi
>>TODAY <- as.POSIXlt('2004-01-17')
>>LYTODAY <- as.POSIXlt('2003-01-17')
>>DAYS <- TODAY-LYTODAY
>>DAYS
Time difference of 365 days
>>DAYS[[1]]
[1] 365
perhaps it helps,
Christian
Dennis Fisher wrote:
I have data in the following format:
DATE
[1] "01/13/2004" In order to find the difference between two data points, I presently use brute force to calculate the day of the year:
strptime(DATE, format="%m/%d/%Y")$yday
[1] 12 Although this works, it may not be robust over different years. I assume that R is sufficiently clever that a much simpler approach exists, e.g., can I calculate the number of days since some fixed time? Unfortunately, the man pages and FAQ did not lead me to an obvious solution. Any help appreciated. Dennis Dennis Fisher MD P < (The "P Less Than" Company) Phone: 1-866-PLessThan (1-866-753-7784) Fax: 1-415-564-2220 www.PLessThan.com
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