MATLAB: Sort( ) do not work (or?)

functionMATLAB

Hello, Got a strange problem with the sort( ) function (I tried with sortrows as well, – same problem exist)..

I just attached the result of two different data tests. In both tests, I show the not sorted data, and the sorted data.. Each number is taken from a 1×1 cell.

Why can it be, that it does not sort the second test?

Hope to hear from someone, thanks in advance.

-best

Best Answer

Both are sorted, but as the quotes around the data show the data are stored as cell strings so it's in ASCII order, not numeric. Convert the cellstring array to numeric prior to sorting...

sort(str2num(char(x)))

or equivalent where x is the cell array.

The first looks ok because all are of the same order of magnitude between 0-1 while the latter change. If you note, they're sorted by the first character of the number in order first.

Related Solutions

MATLAB: Unique characters in a cell

Max - is the order in your output important? If you use first convert your cell array of strings to a single string using strjoin and then use unique to determine the unique characters, you would get

 unique(strrep(strjoin(x'),' ',''))
 ans =
    adeiorst

Note that we use strrep to replace/remove all the space characters in the joined string.

MATLAB: Very simple question about strings

"According to the numbers" is ambiguous.

This sorts the strings in ascending order, making the digit in position 3 more significant than the digit in position 4, etc.:

Asorted = sort(A);

Your example is already sorted by this criterion.

This, on the other hand, makes the last digit the least significant, regardless of how many digits there are. It assumes that there are always 2 characters to ignore at the start:

nums = cellfun(@(s) str2double(s(3:end)), A);
[~, indexes] = sort(nums);
Asorted = A(indexes);

Best Answer

Related Solutions

MATLAB: Unique characters in a cell

MATLAB: Very simple question about strings

Related Question