It works great! Thank you so much Gabor Angelo Linardi
-----Messaggio originale----- Da: Gabor Grothendieck [mailto:[EMAIL PROTECTED] Inviato: giovedì 18 settembre 2008 21.16 A: LINARDI ANGELO Cc: r-help@r-project.org Oggetto: Re: [R] Adding 1 month to a dataframe column Try this: # example data - Jan 31/00, Feb 29/00, Mar 31/00, ..., Dec 31/00 d <- seq(as.Date("2000-02-01"), by = "month", length = 12) - 1 d # find beginning of next month nextmon <- function(d) as.Date(cut(as.Date(cut(d, "month")) + 32, "month")) # add number of days from start of current month to next month nextmon(d) + as.POSIXlt(d)$mday - 1 # If all your dates are at month end and you want the plus 1 month # to be at month end too then replace last line with: nextmon(nextmon(d)) - 1 The last one can be done even more easily with as.yearmon from zoo. It converts the dates to a year plus 0 for jan, 1/12 for feb, etc. Also, as.Date.yearmon(..., frac = 1) converts back from yearmon class to Date class using end of month for the result so: library(zoo) as.Date(as.yearmon(d) + 1/12, frac = 1) On Thu, Sep 18, 2008 at 12:24 PM, <[EMAIL PROTECTED]> wrote: > Dear R experts, > I have a problem in modifying one column of a dataframe with a datatime > format using a datetime operator. > Here is my dataframe A: > > DATACONT PROVINCIA VALORE > 1 2007-12-31 MI 1 > 2 2007-12-31 PV 2 > 3 2007-12-31 NA 3 > 4 2007-12-31 MI 4 > 5 2007-12-31 RM 5 > 6 2007-12-31 RM 6 > 7 2007-12-31 MI 7 > 8 2008-12-31 MI 11 > 9 2008-12-31 PV 12 > 10 2008-12-31 NA 13 > 11 2008-12-31 MI 14 > 12 2008-12-31 RM 15 > 13 2008-12-31 RM 16 > 14 2008-12-31 MI 17 > 15 2006-12-31 MI -9 > 16 2006-12-31 PV -8 > 17 2006-12-31 NA -7 > 18 2006-12-31 MI -6 > 19 2006-12-31 RM -5 > 20 2006-12-31 RM -4 > 21 2006-12-31 MI -3 > > Suppose I want to shift all dates by 1 year, obtaining the following > dataframe B: > > DATACONT PROVINCIA VALORE > 1 2008-12-31 MI 1 > 2 2008-12-31 PV 2 > 3 2008-12-31 NA 3 > 4 2008-12-31 MI 4 > 5 2008-12-31 RM 5 > 6 2008-12-31 RM 6 > 7 2008-12-31 MI 7 > 8 2009-12-31 MI 11 > 9 2009-12-31 PV 12 > 10 2009-12-31 NA 13 > 11 2009-12-31 MI 14 > 12 2009-12-31 RM 15 > 13 2009-12-31 RM 16 > 14 2009-12-31 MI 17 > 15 2007-12-31 MI -9 > 16 2007-12-31 PV -8 > 17 2007-12-31 NA -7 > 18 2007-12-31 MI -6 > 19 2007-12-31 RM -5 > 20 2007-12-31 RM -4 > 21 2007-12-31 MI -3 > > I tried with seq.Date: > seq.Date(a$"DATA",by="1 month",len=2)[2] > > but it works only for single values (the "from" must have length=1). > Any hints ? > Thank you in advance > > Angelo Linardi > > ** Le e-mail provenienti dalla Banca d'Italia sono trasmesse in buona fede e > non > comportano alcun vincolo ne' creano obblighi per la Banca stessa, salvo che > cio' non > sia espressamente previsto da un accordo scritto. > Questa e-mail e' confidenziale. Qualora l'avesse ricevuta per errore, La > preghiamo di > comunicarne via e-mail la ricezione al mittente e di distruggerne il > contenuto. La > informiamo inoltre che l'utilizzo non autorizzato del messaggio o dei suoi > allegati > potrebbe costituire reato. Grazie per la collaborazione. > -- E-mails from the Bank of Italy are sent in good faith but they are neither > binding on > the Bank nor to be understood as creating any obligation on its part except > where > provided for in a written agreement. This e-mail is confidential. If you have > received it > by mistake, please inform the sender by reply e-mail and delete it from your > system. > Please also note that the unauthorized disclosure or use of the message or any > attachments could be an offence. Thank you for your cooperation. ** > > ______________________________________________ > R-help@r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code. > ** Le e-mail provenienti dalla Banca d'Italia sono trasmesse in buona fede e non comportano alcun vincolo ne' creano obblighi per la Banca stessa, salvo che cio' non sia espressamente previsto da un accordo scritto. Questa e-mail e' confidenziale. Qualora l'avesse ricevuta per errore, La preghiamo di comunicarne via e-mail la ricezione al mittente e di distruggerne il contenuto. La informiamo inoltre che l'utilizzo non autorizzato del messaggio o dei suoi allegati potrebbe costituire reato. Grazie per la collaborazione. -- E-mails from the Bank of Italy are sent in good faith but they are neither binding on the Bank nor to be understood as creating any obligation on its part except where provided for in a written agreement. This e-mail is confidential. If you have received it by mistake, please inform the sender by reply e-mail and delete it from your system. Please also note that the unauthorized disclosure or use of the message or any attachments could be an offence. Thank you for your cooperation. ** ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
