R help - Nov 2005 - Comparing rows of matrices with different dimensions

Hi there,

 

I have a question, which I thought is very easy to solve, but somehow I
can't find a solution. Probably someone could help me quickly?

 

Here it is:

 

I have two matrices:

 

a

     [,1] [,2] [,3]

[1,]    1    4    9

[2,]    2    6   10

[3,]    3    6   11

[4,]    4    8   12

 

 

b

     [,1] [,2]

[1,]    1    4

[2,]    2    5

[3,]    3    6

 

Now I want to find out which rows of b can also be found in a (without its last
column). So the solution must be something like either "TRUE FALSE
TRUE" or the rows where their is a match (rows 1 and 3)

 

Till now I have tried things like b %in% a[,1:2] or so but that doesn't work
because I want to compare the WHOLE row of b with the whole row of a without
column 3.

 

Thank you very much for any help.

 

Regards, Antje


	[[alternative HTML version deleted]]

how about:

a <- cbind(1:4, c(4, 6, 6, 8), 9:12)
b <- cbind(1:3, 4:6)
#####
apply(b, 1, paste, collapse = "") %in% apply(a[, -3], 1, paste, 
collapse = "")


I hope it helps.

Best,
Dimitris

----
Dimitris Rizopoulos
Ph.D. Student
Biostatistical Centre
School of Public Health
Catholic University of Leuven

Address: Kapucijnenvoer 35, Leuven, Belgium
Tel: +32/(0)16/336899
Fax: +32/(0)16/337015
Web: http://www.med.kuleuven.be/biostat/
     http://www.student.kuleuven.be/~m0390867/dimitris.htm



----- Original Message ----- 
From: "Antje D??ring" <Antje.Doering at komdat.com>
To: <r-help at stat.math.ethz.ch>
Sent: Monday, November 21, 2005 4:57 PM
Subject: [R] Comparing rows of matrices with different dimensions

>
>
> Hi there,
>
>
>
> I have a question, which I thought is very easy to solve, but 
> somehow I can't find a solution. Probably someone could help me 
> quickly?
>
>
>
> Here it is:
>
>
>
> I have two matrices:
>
>
>
> a
>
>     [,1] [,2] [,3]
>
> [1,]    1    4    9
>
> [2,]    2    6   10
>
> [3,]    3    6   11
>
> [4,]    4    8   12
>
>
>
>
>
> b
>
>     [,1] [,2]
>
> [1,]    1    4
>
> [2,]    2    5
>
> [3,]    3    6
>
>
>
> Now I want to find out which rows of b can also be found in a 
> (without its last column). So the solution must be something like 
> either "TRUE FALSE TRUE" or the rows where their is a match (rows
1
> and 3)
>
>
>
> Till now I have tried things like b %in% a[,1:2] or so but that 
> doesn't work because I want to compare the WHOLE row of b with the 
> whole row of a without column 3.
>
>
>
> Thank you very much for any help.
>
>
>
> Regards, Antje
>
>
> [[alternative HTML version deleted]]
>
> ______________________________________________
> R-help at stat.math.ethz.ch mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide! 
> http://www.R-project.org/posting-guide.html
> 

Disclaimer: http://www.kuleuven.be/cwis/email_disclaimer.htm

If I understand you correctly, 

## not tested

apply(cbind(a[,-3],b),1,function(x)isTRUE(all.equal(x[1:2],x[3:4])))

or something similar. The basic idea is just to drop the last column of a
and check to see whether rows are the same (possible within numeric fuzz).
This assumes order counts. If the rows must just contain the same values
(possibly replicated different numbers of times, then add calls to unique
(or maybe use setdiff if numeric fuzz is not an issue).

HTH

Cheers,
Bert

-- Bert Gunter
Genentech Non-Clinical Statistics
South San Francisco, CA
 
"The business of the statistician is to catalyze the scientific learning
process."  - George E. P. Box
 
 
> -----Original Message-----
> From: r-help-bounces at stat.math.ethz.ch 
> [mailto:r-help-bounces at stat.math.ethz.ch] On Behalf Of Antje D??ring
> Sent: Monday, November 21, 2005 7:57 AM
> To: r-help at stat.math.ethz.ch
> Subject: [R] Comparing rows of matrices with different dimensions
> 
>  
> 
> Hi there,
> 
>  
> 
> I have a question, which I thought is very easy to solve, but 
> somehow I can't find a solution. Probably someone could help 
> me quickly?
> 
>  
> 
> Here it is:
> 
>  
> 
> I have two matrices:
> 
>  
> 
> a
> 
>      [,1] [,2] [,3]
> 
> [1,]    1    4    9
> 
> [2,]    2    6   10
> 
> [3,]    3    6   11
> 
> [4,]    4    8   12
> 
>  
> 
>  
> 
> b
> 
>      [,1] [,2]
> 
> [1,]    1    4
> 
> [2,]    2    5
> 
> [3,]    3    6
> 
>  
> 
> Now I want to find out which rows of b can also be found in a 
> (without its last column). So the solution must be something 
> like either "TRUE FALSE TRUE" or the rows where their is a 
> match (rows 1 and 3)
> 
>  
> 
> Till now I have tried things like b %in% a[,1:2] or so but 
> that doesn't work because I want to compare the WHOLE row of 
> b with the whole row of a without column 3.
> 
>  
> 
> Thank you very much for any help.
> 
>  
> 
> Regards, Antje
> 
> 
> 	[[alternative HTML version deleted]]
> 
> ______________________________________________
> R-help at stat.math.ethz.ch mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide! 
> http://www.R-project.org/posting-guide.html
>

On Mon, 2005-11-21 at 16:57 +0100, Antje D伱伓ring wrote:
>  
> Hi there,
> 
>  
> 
> I have a question, which I thought is very easy to solve, but somehow
> I can't find a solution. Probably someone could help me quickly?
> 
>  
> 
> Here it is:
> 
>  
> 
> I have two matrices:
> 
>  
> 
> a
> 
>      [,1] [,2] [,3]
> 
> [1,]    1    4    9
> 
> [2,]    2    6   10
> 
> [3,]    3    6   11
> 
> [4,]    4    8   12
> 
>  
> 
> 
> 
> b
> 
>      [,1] [,2]
> 
> [1,]    1    4
> 
> [2,]    2    5
> 
> [3,]    3    6
> 
>  
> 
> Now I want to find out which rows of b can also be found in a (without
> its last column). So the solution must be something like either "TRUE
> FALSE TRUE" or the rows where their is a match (rows 1 and 3)
> 
>  
> 
> Till now I have tried things like b %in% a[,1:2] or so but that
> doesn't work because I want to compare the WHOLE row of b with the
> whole row of a without column 3.
> 
>  
> 
> Thank you very much for any help.
> 
>  
> 
> Regards, Antje

Here is one possible approach, though not tested beyond this example:
> which(apply(matrix(b %in% a, dim(b)), 1, all))
[1] 1 3


The steps are:

# which elements of b are in a
> b %in% a
[1]  TRUE  TRUE  TRUE  TRUE FALSE  TRUE


# Turn that into a matrix the same shape as b
> matrix(b %in% a, dim(b))
     [,1]  [,2]
[1,] TRUE  TRUE
[2,] TRUE FALSE
[3,] TRUE  TRUE


# get T/F for which rows are all TRUE
> apply(matrix(b %in% a, dim(b)), 1, all)
[1]  TRUE FALSE  TRUE


# Now get the indices
> which(apply(matrix(b %in% a, dim(b)), 1, all))
[1] 1 3


HTH,

Marc Schwartz