[R] Matrix summary

[Bert Gunter]

Yes, but colMeans, rowMeans, pmax, pmin , etc. are *much* faster.

Cheers,
Bert


Bert Gunter

"The trouble with having an open mind is that people keep coming along
and sticking things into it."
-- Opus (aka Berkeley Breathed in his "Bloom County" comic strip )


On Fri, Feb 12, 2016 at 9:15 PM, Jim Lemon <drjimlemon at gmail.com> wrote:
> Hi Ashta,
> Surely you are aware of the "apply" family of functions that return the
> numbers you want:
>
> ashmat<-matrix(c(117,12,13,21,21,32,11,1,65,43,23,7,58,61,78,95 ),
>  nrow=4,byrow=TRUE)
> apply(ashmat,2,mean)
> [1] 65.25 37.00 31.25 31.00
> apply(ashmat,1,which.max)
> [1] 1 2 1 4
>
> Jim
>
>
> On Sat, Feb 13, 2016 at 3:04 PM, Ashta <sewashm at gmail.com> wrote:
>
>> hi all,
>>
>> I have  a square matrix (1000 by 1000),
>> 1. I want calculate  mean,  min and max values for each column and row.
>>
>> 2, I want pick the  coordinate value of the matrix that has the max
>> and min value for each row and column.
>> This an example 4 by 4 square matrix
>>
>>
>>                                               Mean    Min    Max
>>             117   12    13     21    40.75       12    117
>>              21    32    11       1     16.25       1       32
>>              65    43    23       7      34.5        7       65
>>              58    61    78     95        73        58      95
>> Mean    65    25    37   31.25
>> Min        21    12    11    1
>> Max     117    61    78    95
>>
>>
>> Thank you
>>
>> ______________________________________________
>> R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
>> https://stat.ethz.ch/mailman/listinfo/r-help
>> PLEASE do read the posting guide
>> http://www.R-project.org/posting-guide.html
>> and provide commented, minimal, self-contained, reproducible code.
>>
>
>         [[alternative HTML version deleted]]
>
> ______________________________________________
> R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.