[R] help: how to get the position of a value in a matrix

[wu sz]

Hello,

I have a data set matrix of 1200 * 15. How can I get the position of a
specific value in the matrix?

I use "seq(along = x)[x > value]" to look for the position of the
value in the matrix, but "seq" can just find the sequence position row
by row in the matrix, not a real position (like "rowNumber,
colNumber"). Is any function for that?

Thank you,
Shengzhe