[R] matrices call a function element-wise

[Jonathan P Daily]

IIRC, R is perfectly able to call matrices as vectors, so you might be 
able to do this:

FT <- function(i) fisher.test(matrix(c(A[i],B[i],C[i],D[i]),2))
E <- sapply(1:1000000, FT)

Though I don't know how much time you will save.
--------------------------------------
Jonathan P. Daily
Technician - USGS Leetown Science Center
11649 Leetown Road
Kearneysville WV, 25430
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"Is the room still a room when its empty? Does the room,
 the thing itself have purpose? Or do we, what's the word... imbue it."
     - Jubal Early, Firefly

r-help-bounces at r-project.org wrote on 01/03/2011 09:57:14 AM:

> [image removed] 
> 
> [R] matrices call a function element-wise
> 
> zhaoxing731 
> 
> to:
> 
> R-help
> 
> 01/03/2011 01:46 PM
> 
> Sent by:
> 
> r-help-bounces at r-project.org
> 
> Hello
> 
> I have 4 1000*1000 matrix A,B,C,D. I want to use the corresponding 
> element of the 4 matrices. Using the "for loop" as follow:
> 
> E<-o
> for (i in 1:1000)
>     {for (j in 1:1000)
>  {
>          E<-fisher.test(matrix(c(A[i][j],B[i][j],C[i][j],D[i][j]),
> 2))#call fisher.test for every element
>  }
>     }
> 
> It is so time-consuming
> Need vectorization
> 
> Yours sincerely
> 
> 
> 
> 
> ZhaoXing
> Department of Health Statistics
> West China School of Public Health
> Sichuan University
> No.17 Section 3, South Renmin Road
> Chengdu, Sichuan 610041
> P.R.China
> 
>    [[alternative HTML version deleted]]
> 
> 
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