[R] Comparing two matrices
Dimitris Rizopoulos
dimitris.rizopoulos at med.kuleuven.be
Thu Jul 6 14:43:42 CEST 2006
try something like:
mat1 <- matrix(0, 26, 100, dimnames = list(letters, 1:100))
mat2 <- cbind(sample(letters, 10), sample(100, 10))
###########
mat1[cbind(match(mat2[, 1], rownames(mat1)), match(mat2[, 2],
colnames(mat1)))] <- 1
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://med.kuleuven.be/biostat/
http://www.student.kuleuven.be/~m0390867/dimitris.htm
----- Original Message -----
From: "Srinivas Iyyer" <srini_iyyer_bio at yahoo.com>
To: <r-help at stat.math.ethz.ch>
Sent: Thursday, July 06, 2006 2:18 PM
Subject: [R] Comparing two matrices
> hi:
>
> I have matrix with dimensions(200 X 20,000). I have
> another file, a tab-delim file where first column
> variables are row names and second column variables
> are column names.
>
>
> For instance:
>
>> tmat
> Apple Orange Mango Grape Star
> A 0 0 0 0 0
> O 0 0 0 0 0
> M 0 0 0 0 0
> G 0 0 0 0 0
> S 0 0 0 0 0
>
>
>
>> tb # tab- delim file.
> V1 V2
> 1 Apple S
> 2 Apple A
> 3 Apple O
> 4 Orange A
> 5 Orange O
> 6 Orange S
> 7 Mango M
> 8 Mango A
> 9 Mango S
>
>
> I have to read each line of the 'tb' (tab delim file),
> take the first variable, check if matches any rowname
> of the matrix. Take the second variable of the row in
> and check if it matches any column name. If so, put
> 1 else leave it.
>
>
> The following is a small piece of code that, I felt is
> a solutions. However, since my original matrix and
> tab-delim file is very very huge, I am not sure if it
> is really doing the correct thing. Could any one
> please help me if I am doing this correct.
>
>
>
>> for(i in 1:length(tb[,1])){
> + r = tb[i,1]
> + c = as.character(tb[i,2])
> + tmat[rownames(tmat)==c,colnames(tmat)==r] <-1
> + }
>
>
>
>> tmat
> Apple Orange Mango Grape Star
> A 1 1 1 0 0
> O 1 1 0 0 0
> M 0 0 1 0 0
> G 0 0 0 0 0
> S 1 1 1 0 0
>
>
>
> Thanks.
>
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