[R] Converting Numerical Matrix to List of Strings

[jim holtman]

try this:

> mapping <- c('0'='a', '1'='c', '2'='g', '3'='t')
> x <- matrix(sample(0:3, 30, TRUE), ncol=3)
> x
      [,1] [,2] [,3]
 [1,]    3    1    1
 [2,]    1    3    2
 [3,]    1    1    1
 [4,]    1    1    1
 [5,]    2    1    3
 [6,]    1    3    0
 [7,]    1    3    2
 [8,]    3    1    0
 [9,]    0    3    0
[10,]    3    3    0
> apply(x, 1, function(z){
+     paste(mapping[as.character(z)], collapse='')
+ })
 [1] "tcc" "ctg" "ccc" "ccc" "gct" "cta" "ctg" "tca" "ata" "tta"
>
>


On Sun, Jan 11, 2009 at 10:38 AM, Gundala Viswanath <gundalav at gmail.com> wrote:
> Hi all,
>
> Given a matrix:
>
>> mat
>
>    [,1] [,2] [,3]
> [1,]    0    0    0
> [2,]    3    3    3
> [3,]    1    1    1
> [4,]    2    1    1
>
>
> How can I convert it to a list of strings:
>
>> desired_output
> [1] "aaa" "ttt" "ccc" "gcc"
>
>
> In principle:
>
> 1. Number of Column in matrix = length of string (= 3)
> 2. Number of Row in matrix = length of vector ( = 4).
> 3. Character "a" encode as "0",
>  "c" -> "1",
>  "g" -> "2",
>  "t" -> "3"
>
>
> Length of strings are assumed to be uniform within the vector,
> and it can be greater than 3 (up to 40 characters).
>
>
> - Gundala Viswanath
> Jakarta - Indonesia
>
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>



-- 
Jim Holtman
Cincinnati, OH
+1 513 646 9390

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