Search All of the Math Forum:

Views expressed in these public forums are not endorsed by NCTM or The Math Forum.

Topic: Sort data by relative order
Replies: 2   Last Post: Mar 17, 2013 5:36 AM

 Messages: [ Previous | Next ]
 Nasser Abbasi Posts: 6,447 Registered: 2/7/05
Re: Sort data by relative order
Posted: Mar 16, 2013 6:18 PM

On 3/16/2013 3:30 PM, Joshua wrote:
> Hi all,
>
> This is probably an easy question, but I've had a hard time thinking of how to do this
>efficiently. Basically, I had individual users perform a task multiple times, and have
>sample data below defined as:
>
> Column 1 = User number
> Column 2 = Test Number (Overall)
>

>
> 1 3 1
> 1 4 2

...
> 1 10 8
> 13 15 1
> 13 16 2
> 13 17 3
> 13 18 4
> 13 19 5

starting with your suffled version of your original data , but I

-----------------------
B =
48 41 0
13 18 0
14 36 0
1 4 0
1 10 0
14 35 0
1 3 0
1 5 0
13 19 0
13 22 0
48 42 0
14 37 0
1 7 0
48 38 0
13 20 0
48 39 0
1 9 0
1 6 0
13 17 0
48 40 0
13 21 0
13 23 0
14 34 0
48 43 0
13 15 0
1 8 0
13 16 0
-------------------------

Then one way:

-------------------

B = sortrows(B)
U = unique(B(:,1));
for i = 1:length(U)
idx = find(B==U(i));
B(idx,3) = 1:length(idx)
end
------------------

B =

1 3 1
1 4 2
1 5 3
1 6 4
1 7 5
1 8 6
1 9 7
1 10 8
13 15 1
13 16 2
13 17 3
13 18 4
13 19 5
13 20 6
13 21 7
13 22 8
13 23 9
14 34 1
14 35 2
14 36 3
14 37 4
48 38 1
48 39 2
48 40 3
48 41 4
48 42 5
48 43 6

--Nasser

Date Subject Author
3/16/13 Nasser Abbasi
3/17/13 Bruno Luong