[19091] in s-news-athena
RE: [S] Question on data manipulation
daemon@ATHENA.MIT.EDU (Abd Rahman Kassim)
Wed Sep 1 20:33:38 1999
Message-Id: <01BEF51C.FD1BCEA0.rahmank@frim.gov.my>
From: Abd Rahman Kassim <rahmank@frim.gov.my>
To: "'S-news@wubios.wustl.edu'" <S-news@wubios.wustl.edu>
Date: Thu, 2 Sep 1999 08:27:25 +0800
Dear S-Plus User,
The question was not to find X/mean.X.
But the sum of X for value greater than the subject X.
e.g. plot =1 x=5 relative.x=7+10+6=23,
plot =1 x=7 relative.x=10
Any helps would be appreciated.
Abd Rahman
-----Original Message-----
From: Abd Rahman Kassim [SMTP:rahmank@frim.gov.my]
Sent: Wednesday, September 01, 1999 2:31 PM
To: 'S-news@wubios.wustl.edu'
Subject: [S] Question on data manipulation
Dear S-plus user,
Hi! I have a question on data manipulation. I have a data set as follows:
Data file name : tree.dat
Plot X Mean.X Relative.X
1 5
1 7
1 10
1 6
2 8
2 9
2 2
2 6
where,
Mean X = mean of subject X for each plot
Relative X = relative position of subject Xi to mean X, i.e. Xi/mean X
I calculated the mean x using the aggregate function;
tree.ag<-aggregate(tree.dat[,c("X")],by=Plot,FUN=mean)
I merge the tree.dat with tree.ag to produce new file to produce file with
PLOT, X and Mean.X variables.
Mean.x<-tree.ag$x
Plot<-tree.ag$x
tree.ag<-data.frame(Plot,Mean.X)
tree.mg<-merge(tree.dat,tree.ag)
But how can I calculate the relative X value?
Kindly note that the actual data set has more than 50,000 records and
several relative value will be calculated for different main variables.
Any helps would be appreciated.
Abd Rahman
Hill Forests Silviculture
FRIM
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