Hi,
Your question is still not clear.
May be this helps:
dat2<- read.table(text="
patient_id t scores
1 0 1.6
1 1 2.6
1 2 2.2
1 3 1.8
2 0 2.3
2 2 2.5
2 4 2.6
2 5 1.5
",sep="",header=TRUE)
library(plyr)
dat2New<-ddply(dat2,.(patient_id),summarize,t=seq(min(t),max(t)))
res<-join(dat2New,dat2,type="full")
res1<-do.call(rbind,lapply(split(res,res$patient_id),function(x)
{x1<-x[x$t!=0,];do.call(rbind,lapply(split(x1,((x1$t-1)%/%3)+1),function(y)
{y1<-if(any(y$t==1)) rbind(x[x$t==0,],y) else y;
data.frame(patient_id=unique(y1$patient_id),scores=mean(y1$scores,na.rm=TRUE))})
) }))
row.names(res1)<-1:nrow(res1)
res1$period<-with(res1,ave(patient_id,patient_id,FUN=seq))
res1
# patient_id scores period
#1 1 2.05 1
#2 2 2.40 1
#3 2 2.05 2
A.K.
________________________________
From: GUANGUAN LUO <guanguan...@gmail.com>
To: arun <smartpink...@yahoo.com>
Sent: Tuesday, May 7, 2013 11:29 AM
Subject: Re: how to calculate the mean in a period of time?
Yes ， as you have said, probably , it's not continuous.
2013/5/7 arun <smartpink...@yahoo.com>
Hi,
>Your question is not clear. You mentioned to calculate the mean of 3 months,
>but infact you added the scores for t=0,1,2,3 as first 3 months, then possibly
>4,5,6 as the next. So, it is not exactly three months. Isn't it?
>
>
>Dear R experts,
>sorry to trouble you again.
>My data is like this now :
>patient_id t scores
>1 0 1.6
>1 1 2.6
>1 2 2.2
>1 3 1.8
>2 0 2.3
>2 2 2.5
>2 4 2.6
>2 5 1.5
>
>I want to calculate the mean of period of 3 months, just get a table like this
>
>patient_id period scores
>1 1 2.05
>(1.6+2.6+2.2+1.8)/4
>2 1 2.4
>(2.3+2.5)/2
>2 2 2.05
>(2.6+1.5)/2
>
>thank you in avance
>
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