sortmc

Purpose

Sorts a matrix on multiple columns.

Format

y = sortmc(x, v)
Parameters:
  • x (NxK matrix) – data to be sorted
  • v (Lx1 vector) – contains integers specifying the columns in order, that are to be sorted. If an element is negative, that column will be interpreted as character data.
Returns:

y (NxK matrix) – sorted matrix

Examples

sortmc() keeps all rows together. After it sorts on the first specified column, it will continue to sort the rows of the matrix using the other specified columns ONLY when there is a tie in the first column. For example:

x = { 9 2 5 6,
      3 6 1 9,
      3 7 4 1,
      1 2 8 9 };

s1 = sortc(x, 1);

sm = sortmc(x, 1|2);

will return:

     1      2      8      9
s1 = 3      7      4      1
     3      6      1      9
     9      2      5      6

     1      2      8      9
sm = 3      6      1      9
     3      7      4      1
     9      2      5      6

In the output above, we see that the difference between s1 and sm is that the second and third rows have been switched. This is because sortmc() first sorted the matrix based upon row one like sortc(). Then sortmc() sorted the rows in which the first column was the same (in our example they are both threes), based upon the values in the second column.

Source

sortmc.src

See also

Functions sortd(), sortc(), sortcc(), sorthc(), sorthcc()