A query about na.omit

Dear all,
Say I have the following dataset:

DF
        x     y     z
[1]   1     1     1
[2]   2     2     2
[3]   3     3    NA
[4]   4   NA   4
[5]  NA  5     5

And I want to omit all the rows which have NA, but only in columns X
and Y, so that I get:

 x  y  z
1  1  1
2  2  2
3  3  NA
Roll up your sleeves, and spell out in detail the condition you need:

  DF<-data.frame(x=c(1,2,3,4,NA),y=c(1,2,3,NA,5),z=c(1,2,NA,4,5))
  DF
#    x  y  z
# 1  1  1  1
# 2  2  2  2
# 3  3  3 NA
# 4  4 NA  4
# 5 NA  5  5

  DF[!(is.na(rowSums(DF[,(1:2)]))),]
#   x y  z
# 1 1 1  1
# 2 2 2  2
# 3 3 3 NA

Hoping this helps,
Ted.
If I use na.omit(DF), I would delete the row for which z=NA, obtaining
thus

x y z
1 1 1
2 2 2

But this is not what I want, of course. 
If I use na.omit(DF[,1:2]), then I obtain

x y 
1 1
2 2
3 3

which is OK for x and y columns, but I wouldn't get the corresponding
values for z (ie 1 2 NA)

Any suggestions about how to obtain the desired results efficiently
(the actual dataset has millions of records and almost 50 columns, and
I would apply the procedure on 12 of these columns)?

Sincerely,

Jose Luis 

Jose Luis Iparraguirre
Senior Research Economist 
Economic Research Institute of Northern Ireland

      [[alternative HTML version deleted]]

______________________________________________
R-help at r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
--------------------------------------------------------------------
E-Mail: (Ted Harding) <Ted.Harding at manchester.ac.uk>
Fax-to-email: +44 (0)870 094 0861
Date: 01-Apr-09                                       Time: 18:00:53
------------------------------ XFMail ------------------------------

A query about na.omit

Thread (4 messages)