[R] Number of NA's in every second column

[Dimitris Rizopoulos]

sorry but I misread the part about every second column of the  
data.frame; in this case you could use:

rowSums(sapply(dfr[seq(1, length(dfr), 2)], is.na))

I hope it helps.

Best,
Dimitris


-- 
Dimitris Rizopoulos
Ph.D. Student
Biostatistical Centre
School of Public Health
Catholic University of Leuven

Address: Kapucijnenvoer 35, Leuven, Belgium
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      http://www.student.kuleuven.be/~m0390867/dimitris.htm


Quoting Lauri Nikkinen <lauri.nikkinen at iki.fi>:

> Hi R-users,
>
> How do I calculate a number of NA's in a row of every second column in my
> data frame?
>
> As a starting point:
> dfr <- data.frame(sapply(x, function(x) sample(0:x, 6, replace = TRUE)))
> dfr[dfr==0] <- NA
>
> So, I would like to count the number of NA in row one, two, three etc. of
> columns X1, X3, X5 etc.
>
> Thanks in advance
> Lauri
>
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>
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