[R] help with for loop: new column giving count of observation for each SITEID

[William Dunlap]

Your data was, in R-readable format (from dput())
  d <- data.frame(
       RchID = 1:9,
       site = factor(c("A", "A", "A", "B", "B", "B", "C", 
          "C", "C"), levels = c("A", "B", "C")),
       year = c(2002L, 2004L, 2005L, 2003L, 2006L, 2008L, 
          2002L, 2003L, 2004L),
       index = c(1L, 2L, 3L, 1L, 2L, 3L, 1L, 2L, 3L))
and I am assuming that 'index' is the desired result.  You can use
withinGroupIndex to make a new column identical to 'index'.  There
are a variety of ways to add that column to an existing data.frame,
one of which is within():
  > within(d, newIndex <- withinGroupIndex(site))
    RchID site year index newIndex
  1     1    A 2002     1        1
  2     2    A 2004     2        2
  3     3    A 2005     3        3
  4     4    B 2003     1        1
  5     5    B 2006     2        2
  6     6    B 2008     3        3
  7     7    C 2002     1        1
  8     8    C 2003     2        2
  9     9    C 2004     3        3
Or is 'index' not the desired result?

Bill Dunlap
Spotfire, TIBCO Software
wdunlap tibco.com


> -----Original Message-----
> From: Meredith, Christy S -FS [mailto:csmeredith at fs.fed.us]
> Sent: Tuesday, October 30, 2012 12:20 PM
> To: William Dunlap
> Subject: RE: [R] help with for loop: new column giving count of observation for each
> SITEID
> 
> Not quite,
>  I need it like this, a new number for each ordered year in the sequence within each site,
> regardless of what the years are,  and to retain the RchID column.
> 
> RchID	site	year	index
> 1	A	2002	1
> 2	A	2004	2
> 3	A	2005	3
> 4	B	2003	1
> 5	B	2006	2
> 6	B	2008	3
> 7	C	2002	1
> 8	C	2003	2
> 9	C	2004	3
> 
> 
> Thanks so much for you help!
> 
> 
> -----Original Message-----
> From: William Dunlap [mailto:wdunlap at tibco.com]
> Sent: Tuesday, October 30, 2012 1:07 PM
> To: Meredith, Christy S -FS; r-help at R-project.org
> Subject: RE: [R] help with for loop: new column giving count of observation for each
> SITEID
> 
> Is this what you want?
>   > withinGroupIndex <- function(group, ...) ave(integer(length(group)), group, ...,
> FUN=seq_along)
>   > site <- c("A","A","C","D","C","A","B")
>   > data.frame(site, index=withinGroupIndex(site))
>     site index
>   1    A     1
>   2    A     2
>   3    C     1
>   4    D     1
>   5    C     2
>   6    A     3
>   7    B     1
> 
> You can add more arguments if the groups depend on more than one value:
>   > year <- rep(c(1985, 2012), c(4,3))
>   > data.frame(site, year, index=withinGroupIndex(site, year))
>     site year index
>   1    A 1985     1
>   2    A 1985     2
>   3    C 1985     1
>   4    D 1985     1
>   5    C 2012     1
>   6    A 2012     1
>   7    B 2012     1
> 
> Bill Dunlap
> Spotfire, TIBCO Software
> wdunlap tibco.com
> 
> 
> > -----Original Message-----
> > From: r-help-bounces at r-project.org
> > [mailto:r-help-bounces at r-project.org] On Behalf Of Meredith, Christy S
> > -FS
> > Sent: Tuesday, October 30, 2012 11:17 AM
> > To: r-help at R-project.org
> > Subject: [R] help with for loop: new column giving count of
> > observation for each SITEID
> >
> >
> > Hello,
> > I think this is easy, but I can't seem to find a good way to do this
> > in the R help. I have a list of sites, with multiple years of data for
> > each site id. I want to create a new column that gives a number
> > describing whether it is the 1st year ("1" ) the data was collected
> > for the site, the second year ("2"), etc. I have different years for
> > each siteid, but I don't care which year it was collected, just the order that it is in for
> that siteid.  This is what I have so far, but it doesn't do the analysis separately for each
> SiteID.
> >
> > indexi<-indexg[order(indexg$SiteID,indexg$Yr),]
> >
> > obs=0
> > indexi=na.omit(indexi)
> > for(i in 1:length(indexi$SiteID)){
> > obs=obs+1
> > indexi$obs[i]=obs
> > }
> >
> >
> > Thanks for any help you can give.
> >
> > Christy Meredith
> > USDA Forest Service
> > Rocky Mountain Research Station
> > PIBO Monitoring
> > Data Analyst
> > Voice: 435-755-3573
> > Fax: 435-755-3563
> >
> >
> >
> >
> >
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