how to sort array of time format from min to max time value?

Hi all,

I have a 2-dimension array which its elements are time format, such as 22:13:98. I want to sort each row of this array in the ascending format, I mean from minimum time to maximum time. Any help is appreciated.

[Jan]

To be exact: Most likely "22:13:98" is a string, which means a CHAR vector. Then the "elements" are characters. But perhaps you mean a {N x 1} cell string, and the element is really the string '22:13:98'. So please post the code, which creates a relevant part of your data, such that this important detail is clear.

Answer 1

[Evan]

help sort

Example:

A = magic(5);
sort(A,2)

If you want to convert your time data to a numeric representation for sorting, try datenum.

help datenum

Example:

datenum('22:13:98','hh:mm:ss')

Answer 2

[Jan]

"22:13:98" is a strange example, because times wrap after 59 seconds usually.

I assume these times are stored in a matrix of type CHAR like this:

time = ['22:13:58'; ...
        '22:14:15'; ...
        '21:14:16'];

Then sortrows is sufficient already, because the alphabetical order equals the numerical time order also:

sorted = sortrows(time);

A conversion to the numerical time format would be required and useful only, if you really have mal-formatted times like "22:13:98" and want to compare it with "22:14:37".

[Evan]

Ahhh, that's it. For some reason, I always mistakenly remember being able to pass in 'rows' as an argument to sort instead of the numerical arguments. I had forgotten there was an entirely separate function. This must be what I've been thinking of.

Answer 3

[Azzi Abdelmalek]

A={'22:14:98'  '22:13:98'  '22:15:98';'22:17:98'  '22:18:98'  '22:11:98'}
out=arrayfun(@(x) datestr(x,'HH:MM:SS'),sort(cellfun(@datenum,A),2),'un',0)

[Jan]

Actually I wanted to mention, that CELLFUN and ARRAYFUN can be omitted here, but this does not work at least in R2009a and 2011b:

A = {'22:14:98'  '22:13:98'  '22:15:98';'22:17:98'  '22:18:98'  '22:11:98'};
size(cellfun(@datenum, A))   % [2 x 3] as wanted
size(datenum(A))             % [3 x 1] doe!

But the ARRAYFUN can be omitted:

out = cellstr(datestr(sort(cellfun(@datenum,A),2), 'HH:MM:SS'));
out = reshape(out, size(A));

Anyhow, this isn't substantially nicer or faster. Unfortunately datestr does not reply a cellstring directly.