[R] summary statistics for lists of matrices or dataframes

[Patrick Burns]

No, you can't.  Because 'bind.array' doesn't take an arbitrary number
of arguments.  Robert's solution does what I had in mind.

Patrick Burns wrote:

> 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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>>
>>
>>
>>  
>>
>
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