Sort a cell array of char

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New 2011-4-4

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https://ww2.mathworks.cn/matlabcentral/answers/4684-sort-a-cell-array-of-char

Hi,

I have a cell array of chars (some of the cells should be strings while other should be doubles). Now I am trying to sort several of the rows that should be doubles and I get, of course, a sort from the left of the number as : 1001, 112, 14.. Tried to convert to double with both writing sort(double(...)) and cellfun(@double, ...,'Uniformoutput', false) and it won't accept: 1) ??? Error using ==> double Conversion to double from cell is not possible." 2)??? Error using ==> sort Input argument must be a cell array of strings. What can I do to get 14, 112, 1001... Thank you Keren

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Answer 1

Jan 2011-4-4

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The question is not clear. This is a contradiction:

1. "cell array of chars" 2. "(some of the cells should be strings while other should be doubles)"

From the later text I guess, you want to sort a cell vector which contains scalar doubles:

C = {1001, 112, 14};
[dummy, index] = sort([C{:}]);
sortedC = C(index);

CELLFUN(@double, ...) converts each element of the cell to a DOUBLE - therefore it does no change anything here!

EDITED: Now a method to sort a cell string according to the numbers the strings represent:

C = {'1001', '112', '14'};
Str = sprintf('%s,', C{:});
D = sscanf(Str, '%g,');
[dummy, index] = sort(D);
sortedC = C(index);

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Jan 2011-4-4

Does the above added sorting method help?

New 2011-4-4

Yes! Thank you! I would never think of doing something like this.

There is no direct way to sort such cell array?

Anyway, thank you very much.

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Answer 2

Teja Muppirala 2011-4-4

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Instead of just "double" you should use "str2double". I'm pretty sure that does what you want.

A = {'1001', '112', '14'}
B = str2double(A)
[Bsorted,ordering] = sort(B)

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Teja Muppirala 2011-4-4

Wow, that's pretty slick! I wouldn't have thought of that.

Jan 2011-4-4

And SPRINTF still wastes time, because it does not pre-allocate the output. Therefore using http://www.mathworks.com/matlabcentral/fileexchange/26077-cstr2string will make it twice as fast:

tic; e = sscanf(CStr2String(C, ','), '%g,'); toc % 0.005 sec

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