R help - Oct 2013 - How would i sum the number of NA's in multiple vectors

mattbju2013 wrote
> Hi guys this is my first post, i need help summing the number of NA's
in a
> few vectors
> 
> for example..
> 
> c1<-c(1,2,NA,3,4)
> c2<-c(NA,1,2,3,4)
> c3<-c(NA,1,2,3,4)
> 
> how would i get a result that only sums the number of NA's in the
vector?
> the.result.i.want<-c(2,0,1,0,0)
See ?is.na .   
Now, if I can interpret your question correctly, you're actually looking for
the number of NA per *position* in the vectors, so let's make them into a
matrix first.

cmat<-rbind(c1,c2,c3)
then use apply over columns
apply(cmat,2,function(k)sum(is.na(k)))





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Or faster (both computational speed and amount of code):

colSums(is.na(rbind(c1, c2, c3)))


On Thu, Oct 17, 2013 at 4:34 AM, Carl Witthoft <carl@witthoft.com> wrote:
> mattbju2013 wrote
> > Hi guys this is my first post, i need help summing the number of
NA's in
> a
> > few vectors
> >
> > for example..
> >
> > c1<-c(1,2,NA,3,4)
> > c2<-c(NA,1,2,3,4)
> > c3<-c(NA,1,2,3,4)
> >
> > how would i get a result that only sums the number of NA's in the
vector?
> > the.result.i.want<-c(2,0,1,0,0)
>
> See ?is.na .
> Now, if I can interpret your question correctly, you're actually
looking
> for
> the number of NA per *position* in the vectors, so let's make them into
a
> matrix first.
>
> cmat<-rbind(c1,c2,c3)
> then use apply over columns
> apply(cmat,2,function(k)sum(is.na(k)))
>
>
>
>
>
> --
> View this message in context:
>
http://r.789695.n4.nabble.com/How-would-i-sum-the-number-of-NA-s-in-multiple-vectors-tp4678411p4678432.html
> Sent from the R help mailing list archive at Nabble.com.
>
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> PLEASE do read the posting guide
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> and provide commented, minimal, self-contained, reproducible code.
>


-- 
Joshua Wiley
Ph.D. Student, Health Psychology
University of California, Los Angeles
http://joshuawiley.com/
Senior Analyst - Elkhart Group Ltd.
http://elkhartgroup.com

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