Sort matrix by datenum

I have a 88416 x 13 matrix. Column 1 contains the datenum values. I want to sort the matrix by column 1 keeping the corresponding values. It must be sorted from oldest to newest and keep the corresponding values

Answer 1

[Stephen23]

Where M is your matrix, use sortrows and its second optional argument to select the column:

sortrows(M,1)

Answer 2

[Peter Perkins]

If using MATLAB R2016b or newer, you might consider using a timetable. There are lots of benefits beyond simple sorting by time, but here's how you'd do that:

>> tt = timetable(datetime(2017,5,[1;3;2;5;4]),randn(5,1),randn(5,1),randn(5,1))
tt =
  5×3 timetable
        Time         Var1        Var2        Var3   
    ___________    ________    ________    _________
    01-May-2017     -0.1469    -0.60006      0.96697
    03-May-2017    -0.85955    -0.78089    -0.075429
    02-May-2017     0.69933    -0.74781     -0.58065
    05-May-2017     0.94991     0.62544       1.3161
    04-May-2017     0.41305     -1.3237       1.2532
>> sortrows(tt)
ans =
  5×3 timetable
        Time         Var1        Var2        Var3   
    ___________    ________    ________    _________
    01-May-2017     -0.1469    -0.60006      0.96697
    02-May-2017     0.69933    -0.74781     -0.58065
    03-May-2017    -0.85955    -0.78089    -0.075429
    04-May-2017     0.41305     -1.3237       1.2532
    05-May-2017     0.94991     0.62544       1.3161

Prior to R2016b, you could also use a table that contains a datetime variable. sortrows would also work on that.