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Hello All,
I have a tapply problem, which I thought was an easy one, but the solution has nonetheless eluded me (more coffee?).
My dataframe structure is this:
index R1 R2......................R40
A NA 345.6
C non-detect non-detect
B 1.03 NA
B 1.55 NA
A NA 234.5
C non-detect NA
.
.
.
What I need are simultaneous counts of 1) NA's and 2) non-detect's for each column Rx, for each index (n=3), across some 40 columns and some 150K records. My idea is to cbind the results of this query into a dataframe for analysis. I just can't seem to get the correct syntax.
I should say that I have tried flipping between a datatype of factor and character for both the index and the Rx's, but that hasn't helped me, probably since I don't have the syntax of the command correct yet.
A further question is, then, what is the (more?) correct datatype (factor or char) for both index and data columns, for proper input into tapply?
I hope I am clear enough with my explanation.
best regards,
Mike Slattery
Michael W. Slattery
Geologist, Ohio EPA
50 West Town Street, Suite 700
Columbus OH, 43215
michael.slattery@epa.state.oh.us
614-728-1221 (Ph)
614-644-2909 (Fax) |