[R] Merging vector data into one file

Mark Altaweel maltaweel at anl.gov
Mon Feb 1 05:22:32 CET 2010


Hi,

I had another question. If you had say a vector (e.g., called data)  
with 235 elements and each element looked like the following

data[[1]]
Column A-B    Column Z-S    Column A-S....
1	                  2                        5 .......


data[[2]]
Column Z-B    Column A-S    Column A-B....
2	                  1                        3 .......



Anyway, each element consists of one row that lists the names of the  
columns and the second row is the counts of those columns. What I  
wanted to do is merge all the elements from the vector  so that I  
aggregate the counts for every column in the vector elements. So if a  
column name (e.g., Column A-B) is present in two elements, then I  
would want those elements that have the same column name to aggregated  
their counts; however, if the column name is unique then I simply just  
want to integrate that column with the total. The example below shows  
the result of what I mean using the two elements above:


result=data[[1]] + data[[2]].......

Column A-B    Column Z-S    Column A-S    Column Z-B.........
4                        2                        6			      2.......



So what I want would take the 235 elements, aggregate the column names  
and counts, and produce one output  variable (e.g., called result)  
that has all the column names and counts present in the 235 elements.  
I tried using sapply, (e.g., sapply(data,function(.df){sum(.df)}) ),  
but this only just provided aggregate counts without producing the  
column names.  I tried an aggregate() function, but that didnt  
aggregate my data exactly the way I wanted, perhaps I got the syntax  
wrong though. Anyway, is there a better and easier way to do this?

Thanks in a advance again.

Mark



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