you are right Jeff and sorry for this I will try to explain what I want.
I have the following dataset dat <- data.frame("country" = c(rep(1,4)), "date" = c("23/11/08","28/12/08","25/01/09","22/02/09"), "price" = c(2,3,4,5)) Normally, prices are observed every 4 weeks (28 days). Each observation that it is published is a 4-week average. In some cases, though, I have jumps (35 days-see from "23/11/08" to "28/12/08"). So some prices that are published are 5-week average I want to interpolate the 4-week average prices to monthly prices so as to have dat <- data.frame("country" = c(rep(1,4)), "date" = c("11/08","12/08","01/09","02/09"), "price" = c(3,2,1,4)) where the "new" "price" = c(3,2,1,4) will contain the interpolated prices. So by starting what I have , that is, - "price" = c(2,3,4,5)) -I want to calculate monthly average prices via interpolation. I hope to have been more explicit. thank you and apologies for one more time, On 6/17/12, Jeff Newmiller <jdnew...@dcn.davis.ca.us> wrote: > stop repeating yourself. and stop asking us to do your work. > > Try reading the posting guide. Give us an example of the output you DO want. > Show us the code you already have. Use the dput function to give us example > data to work with. Learn to use the str function so you know what data you > are really working with. Ask specific questions. > --------------------------------------------------------------------------- > Jeff Newmiller The ..... ..... Go Live... > DCN:<jdnew...@dcn.davis.ca.us> Basics: ##.#. ##.#. Live Go... > Live: OO#.. Dead: OO#.. Playing > Research Engineer (Solar/Batteries O.O#. #.O#. with > /Software/Embedded Controllers) .OO#. .OO#. rocks...1k > --------------------------------------------------------------------------- > > Sent from my phone. Please excuse my brevity. > > > > stef salvez <loggy...@googlemail.com> wrote: > >>Dear R users, >>I have a panel data set (in MS excel) on prices across countries and >>time >> >>country time price >> 1 "23/11/08" 2 >>1 "28/12/08" 3 >>1 "25/01/09" 4 >>1 "22/02/09" 5 >>1 "29/03/09" 6 >>1 "26/04/09" 32 >>1 "24/05/09" 23 >>1 "28/06/09" 32 >>2 "26/10/08" 45 >>2 "23/11/08" 46 >>2 "21/12/08" 90 >>2 "18/01/09" 54 >>2 "15/02/09" 65 >>2 "16/03/09" 77 >>2 "12/04/09" 7 >>2 "10/05/09" 6 >> >> >>As you can see, >> >>1)the start and end date of the time series for countries 1 and 2 are >>different. For example, for country 1 the time series begins on >>"23/11/08" while for country 2 the time series begins on "26-10-2008”. >> >>2)My data on prices are available every 28 days (or equivalently every >>4 >>weeks). So, each observation is a 4-week average. But in some cases I >>have jumps (35 days or 29 days instead of >>28 days). For example from the above table we have such jumps: from >>"28/12/08" to "28/12/08" , from 22/02/09" to "29/03/09", etc >> >>My goal is to have a unified sequence of dates across countries. >>Otherwise I will not be able to do further data/econometric analysis, >>Unless you have different suggestion, I want to take what I have and >>calculate monthly average prices and also report how many prices those >>averages are based on. I suppose that I will still have gaps and may >>well need to interpolate. >> >>Put differently, I want to interpolate the 4-week average prices to >>monthly average prices. >>The problem is also the jumps where I have 5 weeks in some cases and I >>want to find the monthly average of it. >> I do not want something like >> >> country yearmon avg.price freq >>1 1 Nov 2008 2 1 >>2 1 Dec 2008 3 1 >>3 1 Jan 2009 4 1 >>4 1 Feb 2009 5 1 >>5 1 Mar 2009 6 1 >>6 1 Apr 2009 32 1 >>7 1 May 2009 23 1 >>8 1 Jun 2009 32 1 >>9 2 Oct 2008 45 1 >>10 2 Nov 2008 46 1 >>11 2 Dec 2008 90 1 >>12 2 Jan 2009 54 1 >>13 2 Feb 2009 65 1 >>14 2 Mar 2009 77 1 >>15 2 Apr 2009 7 1 >>16 2 May 2009 6 1 >> >> >>Please, I would be grateful to you if you could provide the exact code >>for doing this >> >>thank you >> >>______________________________________________ >>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. > > ______________________________________________ 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.