Re: Function for summarizing the table to two factors and a frequency

[David L Lorenz <lorenz@usgs.gov>]

Jagadish,
  The tapply() function will produce
a summary table that you want. Note that this version return a matrix if
no more than 1 value is found for n1 or n2. The I() function simply returns
what is passed to it.
Dave
> tapply(Junk$n1, Junk[,1:2], I)
           112  
    114      142       312 342

311  239.87344 166.50672 870.5615 120.39770  
1
313   27.75878  19.03609 197.4086  35.53144
 NA
341 1346.87779 553.11880 969.2233      
 NA  NA

Jagadish Rangrej <jrangrej@yahoo.com>
Sent by: s-news-owner@lists.biostat.wustl.edu

12/07/2005 04:16 PM

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Subject	[S] Function for summarizing the table to two factors and a frequency

Hello,

is there a generic function which can generate the
summary table (like the one generated by 'table'
function in splus/R) based on two factors and a column
of counts

I have a table of n x 4 out of which the 1st two are
factors and other two are counts for case and control
resp.. I need to generate either a table of 3
dimensions f1 x f2 x 2, or two tables of f1 x f2 size
with there dimnames matched for both controls and
cases.

Here is an example:
mydata = 
      f1     f2    n1    
     n2
1     311    112  239.87344  239.829302
2     311    114  166.50672  168.512009
3     311    142  870.56154  869.301191
4     311    312  120.39770  119.280942
5     311    342    1.00000   -1.308982
6     313    112   27.75878   27.834905
7     313    114   19.03609   19.961629
8     313    142  197.40857  198.818765
9     313    312   35.53144   34.929056
10    341    112 1346.87779 1346.927249
11    341    114  553.11880  553.609228
12    341    142  969.22327  969.618471

---------------------------------------
   f2
f1      112 114 142 312 342
   311   1   1   1   1   1
   313   1   1   1   1   0
   341   1   1   1   1   1
   343   1   1   1   1   0
   411   1   1   1   1   0
   413   0   0   1   0   0
   441   1   1   1   1   0
   443   1   0   0   0   0

but instead of '1's in three I need a N1, and N2's.


all help will be greatly appreciated,
Jag




                
                 
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