R help - Nov 2007 - How to select rows with identical index from two matrix?

Dear list,

    I have two martix like these, each rows with name in the matrix. 

    I try to select rows with identical name from two matrix and calculate their
correlation.

Matrix1:
2-Sep    9     5.5    1     7.18     10.0    8     139.45
2-Sep    7     4.9    15   8.22     61.68  9     123.62
4-Sep
5-Sep
AAMP
A2M
A2M
.
.
.

Matrix2:

2-Sep     4     7    1     6.8     12    8      19.4
2-Sep      2    8    15   2.2     6.8   12     13.2
4-Sep
AAMP
AAMP
ABCA5
A2M
A2M

I try to select rows with identical name from two matrix and calculate their
correlation.

However, I got trouble when loading these two matrix into R as header=TRUE. 

So I use header=FLASE and these name become character in the first column.  

How do I extract the first column of matrix 1 and compare to the first column of
matrix 2?

And if they are identical I compute their correlation?


SIncerely yours,
Chiahsin Liu

	[[alternative HTML version deleted]]

You can do the following:

set1 <- Matrix1[,1]
set2 <- Matrix2[,1]
common <- intersect(set1,set2)
ind1 <- which(set1 %in% common)
ind2 <- which(set2 %in% common)

A1 <- Matrix1[ind1,-1]
A2 <- Matrix2[ind2,-1]

and if you wish,

rownames(A1) <- common
rownames(A2) <- common

--- "C.S. Liu" <qnerv at stat.sinica.edu.tw> wrote:
> Dear list,
> 
>     I have two martix like these, each rows with
> name in the matrix. 
> 
>     I try to select rows with identical name from
> two matrix and calculate their correlation.
> 
> Matrix1:
> 2-Sep    9     5.5    1     7.18     10.0    8    
> 139.45
> 2-Sep    7     4.9    15   8.22     61.68  9    
> 123.62
> 4-Sep
> 5-Sep
> AAMP
> A2M
> A2M
> .
> .
> .
> 
> Matrix2:
> 
> 2-Sep     4     7    1     6.8     12    8      19.4
> 2-Sep      2    8    15   2.2     6.8   12     13.2
> 4-Sep
> AAMP
> AAMP
> ABCA5
> A2M
> A2M
> 
> I try to select rows with identical name from two
> matrix and calculate their correlation.
> 
> However, I got trouble when loading these two matrix
> into R as header=TRUE. 
> 
> So I use header=FLASE and these name become
> character in the first column.  
> 
> How do I extract the first column of matrix 1 and
> compare to the first column of matrix 2?
> 
> And if they are identical I compute their
> correlation?
> 
> 
> SIncerely yours,
> Chiahsin Liu
> 
> 	[[alternative HTML version deleted]]
> 
> ______________________________________________
> R-help at r-project.org mailing list
> 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.
>