[R] Extracting months and years from Dates while keeping order

From: Dimitri Liakhovitski <dimitri.liakhovitski_at_gmail.com>
Date: Fri, 06 May 2011 16:07:19 -0400


Hello!

I'd like to take Dates and extract from them months and years - but so that it sorts correctly. For example:

x1<-seq(as.Date("2009-01-01"), length = 14, by = "month")
(x1)

order(x1) # produces correct order based on full dates

# Of course, I could do "format" - but this way I am losing the "Date" quality of the data:

x2<-format(x1,"%Y.%m")
(x2)

order(x2)

Not sure it's possible at all: But is there some other way to extract just months and years from Dates (while ingoring days) - but so that it's still somehow a Date object?

Thank you very much!

-- 
Dimitri Liakhovitski
Ninah Consulting
www.ninah.com

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Received on Fri 06 May 2011 - 20:09:32 GMT

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