How to sort a matrix based on two columns

Assume matrix A as follows:

A = [
1  1  20
1  2  32
1  3  10
2  1  45
2  2  10
2  3  15
3  1  43
3  2  90
];

I want to sort matrix A based on the third column. However, I want to keep the first column also sorted. Whenever the ID changed, then column 3 is sorted. The output should be something likes:

B = [
1  3  10
1  1  20
1  2  32
2  2  10
2  3  15
2  1  45
3  1  43
3  2  90
];

[Stephen23]

@Zhan: you keep asking questions, but you have not accepted any of the answers to any of your questions. Accepting answers shows which answer solved your question, and is also an easy way for you to say "thank you" for our volunteer effort helping you.

Answer 1

[dpb]

>> sortrows(A,[1 3 2])          % doc sortrows for details...
ans =
   1     3    10
   1     1    20
   1     2    32
   2     2    10
   2     3    15
   2     1    45
   3     1    43
   3     2    90
>>

[pepijn schrage]

Sweet! I hoped it would be something this elegant. Thanks for the answer!

[Muhammad Bilal]

plz anyone can explain sortrows(A,[1 3 2]) ?

thanks

[dpb]

>> help sortrows
 sortrows Sort rows of a matrix.
    B = sortrows(A) sorts the rows of matrix A in ascending order as a
    group. B has the same size and type as A. A must be a 2-D matrix.
 
    B = sortrows(A,COL) sorts the matrix according to the columns specified
    by the vector COL.  If an element of COL is positive, the corresponding
    column in A is sorted in ascending order; if an element of COL is
    negative, the corresponding column in A is sorted in descending order.
    For example, sortrows(A,[2 -3]) first sorts the rows in ascending order
    according to column 2; then, rows with equal entries in column 2 get
    sorted in descending order according to column 3.
    
    ...

So,

sortrows(A,[1 3 2])          % doc sortrows for details...

sorts A in ascending order by column order of first, third, second. This can be seen to be so by inspection of the output.