Preallocating a cell array of chars?

38 views (last 30 days)
Is there a better way of preallocating a cell array of empty chars than using a for loop or deal? Cells can contain any data type, yet if I create a empty cell array, it is always type double.
>> A = cell([3,1])
A =
3×1 cell array
{0×0 double}
{0×0 double}
{0×0 double}
>> for i = 1:length(A), A{i} = ''; end
>> A
A =
3×1 cell array
{0×0 char}
{0×0 char}
{0×0 char}

Accepted Answer

Stephen23
Stephen23 on 27 Oct 2020
Edited: Stephen23 on 27 Oct 2020
A = cell(3,1);
A(:) = {''}
This assigns one scalar cell (on the RHS) to all of the cells in the array A:
Or simply use
A = repmat({''},3,1);
  1 Comment
Monika Jaskolka
Monika Jaskolka on 27 Oct 2020
Thanks. Looks like the your first approach is fastest for my case.
>> len = 1000000;
>> A = cell([len, 1]); tic; A(:) = {''}; toc % assignment
Elapsed time is 0.013068 seconds.
>> A = cell([len, 1]); tic; A = repmat({''},len,1); toc % repmat
Elapsed time is 0.024813 seconds.
>> A = cell([len, 1]); tic; for i = 1:length(A), A{i} = ''; end, toc % for loop
Elapsed time is 0.183295 seconds.
>> A = cell([len, 1]); tic; [A{:}] = deal(''); toc % deal
Elapsed time is 0.293894 seconds.

Sign in to comment.

More Answers (0)

Products


Release

R2020a

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!