grouping elements of a matix according to an increasing order of dates

Hi all,

i have a matrix A which I have sorted according to the command zoi=sortrows(A, 3 ) and the result is zoi=

         'PDL12'    '01-01-2011'    [     -0.0138]

         'PDL13'    '01-01-2011'    [      0.3529]

         'PDL12'    '01-11-2009'    [     -0.0812]

         'PDL13'    '01-11-2009'    [     -0.2377]

             'PDL12'    '04-10-2009'    [     -0.0208]

And I would like to have

             'PDL12'    '04-10-2009'    [     -0.0208]

         'PDL12'    '01-11-2009'    [     -0.0812]

         'PDL13'    '01-11-2009'    [     -0.2377]

        'PDL12'    '01-11-2009'    [     -0.0812]

         'PDL13'    '01-01-2011'    [      0.3529]

In other words, i want to group all the elements that correspond to the earliest date, then all the elements that correspond to the date after the earliest one and so forth. Any suggestions?

thanks

Answer 1

a={         'PDL12'    '01-01-2011'    [     -0.0138]
'PDL13'    '01-01-2011'    [      0.3529]
'PDL12'    '01-11-2009'    [     -0.0812]
'PDL13'    '01-11-2009'    [     -0.2377]
'PDL12'    '04-10-2009'    [     -0.0208]}
d=datenum(a(:,2),'dd-mm-yyyy');
[l,idx]=sortrows(d);
a(idx,:)                     % output

Excellent!