[R] substituting level for NA in factor column

Kurt_Helf at nps.gov Kurt_Helf at nps.gov
Tue Jan 18 23:25:36 CET 2011


Greetings
     I have a bunch of NAs in a column of categorical variables designating
the size classes (e.g., smallest to largest: 1,2,3,4) of cave crickets.
I'd like to substitute "U" (for unknown) for the NAs.  Can anyone give me
an idea how to do this?  Thanks in advance.
Cheers
Kurt

***************************************************************
Kurt Lewis Helf, Ph.D.
Ecologist
EEO Counselor
National Park Service
Cumberland Piedmont Network
P.O. Box 8
Mammoth Cave, KY 42259
Ph: 270-758-2163
Lab: 270-758-2151
Fax: 270-758-2609
****************************************************************
Science, in constantly seeking real explanations, reveals the true majesty
of our world in all its complexity.
-Richard Dawkins

The scientific tradition is distinguished from the pre-scientific tradition
in having two layers.  Like the latter it passes on its theories but it
also passes on a critical attitude towards them.  The theories are passed
on not as dogmas but rather with the challenge to discuss them and improve
upon them.
-Karl Popper

...consider yourself a guest in the home of other creatures as significant
as yourself.
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CUPN Forest Pest Monitoring Website:
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CUPN Cave Cricket Monitoring Website:
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