From: <markleeds_at_verizon.net>

Date: Tue 04 Jul 2006 - 06:37:58 EST

https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html Received on Tue Jul 04 06:42:22 2006

Date: Tue 04 Jul 2006 - 06:37:58 EST

suppose i have a matrix in which some column names are identical so, for example, TEMP

** "AAA", "BBB", "CCC", "DDD","AAA", "BBB"
**

0 2 1 2 0 0 2 3 7 6 0 1 1.5 4 9 9 6 0 1.0 6 10 11 3 3

I didn't even check yet whether identical column names are allowed in a matrix but i hope they are.

assuming that they are, then i would like to be able to take the matrix and make a new matrix with the following requirements.

- whenever there is a unique column name, just take that column for the new matrix
- whenever the column name is not unique, take the one that has the most non zero elements ? ( in the case of ties, i don't care which one is picked ).

so, in this case, the resulting matrix would just be the first 4 columns.

i realize ( or atleast i think ) that

sum( TEMP[(TEMP[,columnname] !=0) ,columnname) will give me the
number of non elements in a column with the name columnmame
but how to use this deal with the non uniqueness to solve my particular problem is beyond me. plus, i think the command will
bomb because columnname will not always be unique ?
Thanks for any help. I realize this is not a trivial problem so I really appreciate it.

Mark ______________________________________________R-help@stat.math.ethz.ch mailing list

https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html Received on Tue Jul 04 06:42:22 2006

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