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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