See ?is.na
Uwe Ligges
Benjamin M. Osborne wrote:
I want to know where all the NAs are in a matrix. The data frame looks like this:
vmc[1:5,]
date year month day snow.new prcp tmin snow.dep tmax 1 01NOV1954 1954 11 1 NA NA -14.44444 NA 12.2222222 2 02NOV1954 1954 11 2 NA NA -13.88889 NA 2.2222222 3 03NOV1954 1954 11 3 NA NA -16.66667 NA -1.1111111 4 04NOV1954 1954 11 4 NA NA NA NA -0.5555556 5 05NOV1954 1954 11 5 NA NA -17.22222 NA -2.7777778 tmean yearmo 1 -1.111111 195411 2 -5.833333 195411 3 -8.888889 195411 4 NA 195411 5 -10.000000 195411
This does not work:
subset(vmc, snow.new==NA)
[1] date year month day snow.new prcp tmin snow.dep [9] tmax tmean yearmo <0 rows> (or 0-length row.names)
Because:
NA==NA
[1] NA
How can I return all rows of this data frame that contain NA in a particular field?
Thanks, Ben Osborne
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