[R] summary statistics for lists of matrices or dataframes

[Patrick Burns]

You could use 'do.call' with 'bind.array' (from S Poetry) or 'abind'
to convert your list of matrices into a three-dimensional array.

Patrick Burns

Burns Statistics
patrick at burns-stat.com
+44 (0)20 8525 0696
http://www.burns-stat.com
(home of S Poetry and "A Guide for the Unwilling S User")

David Kane wrote:

>Is there a simple way to calculate summary statistics for all the
>matrices or dataframes in a list? For example:
>
>  
>
>>z <- list(matrix(c(2,2,2,2), ncol = 2), matrix(c(4,4,4,4), ncol = 2))
>>z
>>    
>>
>[[1]]
>     [,1] [,2]
>[1,]    2    2
>[2,]    2    2
>
>[[2]]
>     [,1] [,2]
>[1,]    4    4
>[2,]    4    4
>  
>
>
>I would like to calculate, for example, the mean value for each
>cell. I can do that the hard way as:
>
>  
>
>>(z[[1]] + z[[2]]) / 2
>>    
>>
>     [,1] [,2]
>[1,]    3    3
>[2,]    3    3
>  
>
>
>But there must be an easier way. I am also interested in other
>statistics (like median and sd). Since all my matrices have the same
>attributes (especially row and column names), I would like to preserve
>those in the answer.
>
>Thanks,
>
>Dave Kane
>
>In case it matters:
>
>  
>
>>R.version
>>    
>>
>         _                
>platform i686-pc-linux-gnu
>arch     i686             
>os       linux-gnu        
>system   i686, linux-gnu  
>status                    
>major    2                
>minor    1.0              
>year     2005             
>month    04               
>day      18               
>language R                
>  
>
>
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>
>
>
>  
>