r - Matching patterns in a matrix -

my data looks this:

                         s   0101001010000000000000000100111100000000000011101100010101010 1001010000000001100000000100000000000100000010101110101010010 1101010101010010000000000100000000100101010010110101010101011 0000000000000000001000000111000110000000000000000000000000000 

the s indicates column talking. col 26. 4 rows share 1 @ position.

i need able count each row 2 4:

• how many columns left , right same row 1?

for row 2 3 right (as reaches 1/0) , 8 left (as reaches 0/1).

the result every row should entered matrix this:

row2 8 3 row3 11 9 

is there fast , efficient way that? matrix dealing large.

if need fast, use rcpp:

mat <- as.matrix(read.fwf(textconnection("0101001010000000000000000100111100000000000011101100010101010 1001010000000001100000000100000000000100000010101110101010010 1101010101010010000000000100000000100101010010110101010101011 0000000000000000001000000111000110000000000000000000000000000"), widths = rep(1, 61)))   library(rcpp)  cppfunction('     integermatrix countlr(const logicalmatrix& mat, const int s) {        const int nr(mat.nrow()), nc(mat.ncol());        integermatrix res(nr - 1, 2);        for(int i=1; i<nr;i++){          for(int j=s-2; j>=0;j--) {            if (mat(0,j) != mat(i,j)) break;            else res(i-1,0)++;          }          for(int j=s; j<nc;j++) {            if (mat(0,j) != mat(i,j)) break;            else res(i-1,1)++;          }        }        return(res);     }' )    countlr(mat, 26) #     [,1] [,2] #[1,]    8    2 #[2,]   10    2 #[3,]    6    0 

i assumed column 26 doesn't count result. assumed matrix can contain 0/1 (i.e., boolean) values. adjust needed.