Hi,
Try this:
dattrial<-data.frame(a=c(1,NA,rnorm(4,10)), Week=c(3,3,3,4,4,4))
?aggregate(dattrial$a,list(dattrial$Week),function(x) sum(is.na(x)))
#? Group.1 x
#1?????? 3 1
#2?????? 4 0
#or
?ddply(dattrial,.(Week),summarize, sum(is.na(a)))
#? Week ..1
#1??? 3?? 1
#2??? 4?? 0
#or
list1<-split(dattrial,dattrial$Week)
?unlist(lapply(lapply(list1,`[`, 1),function(x) sum(is.na(x))))
#3 4
#1 0
A.K.
----- Original Message -----
From: Tagmarie <Ramgad82 at gmx.net>
To: r-help at r-project.org
Cc:
Sent: Monday, September 17, 2012 6:03 AM
Subject: [R] count NAs per week
Even though I work with R since a year or so I still struggle with simple
problems. I hope someone can help me with this. Been trying for days and am
a little frustrated now.
I have a data frame somewhat like the one bellow:
dattrial<-data.frame(a=c(1,NA,rnorm(4,10)), Week=c(3,3,3,4,4,4))
I want to know how many NAs I have in week 3 and in week 4.
--
View this message in context: http://r.789695.n4.nabble.com/count-NAs-per-week-tp4643351.html
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