mtx2charcell

Converts a matrix of numbers into a cell array of strings.

Description

%charcell = mtx2charcell(mtx)
% Converts a matrix of numbers into a cell array of strings of the same
% dimensionality as MTX.
%charcell = mtx2charcell(mtx,fmt)
% Uses the format string FMT (see SPRINTF for details).
%
%This function serves as a shorthand for using the built-in NUM2CELL,
%NUM2STR, and RESHAPE commands together (thanks Urs Schwarz!)
%
%EXAMPLES:
% mtx2charcell([0 1 2]) --> {'0.000000', '1.000000', '2.000000'}
% mtx2charcell([0 1 2], '%d') --> {'0', '1', '2'}
%
%This function can be handy to use in conjunction with the author's JOIN
%function (also available on Matlab Central). For example,
% join('-', mtx2charcell([0 1 2], '%d')) --> '0-1-2'
%
%CHANGES:
% 2006-02-16 6pm: even better performance enhancement, thanks to Urs Schwarz
% 2006-02-16 afternoon: performance enhancement thanks to Jiro Doke.

• MATLAB release: MATLAB 7.0.4 (R14SP2)

[Jiro Doke]

Nice, I've had a need for something like this. But the loop can be sped up by vectorizing and using strread:

%-----------------------
mtx=[1:100000];

fmt='%8.2f';

tic;
charcell1=cell(size(mtx));
for i=1:numel(mtx)
  charcell{i}=sprintf(fmt, mtx(i));
end
toc;

tic;
charcell2=strread(sprintf([fmt ','],mtx),'%s',...
  'delimiter',',','whitespace','');
charcell2=reshape(charcell2,size(mtx));
toc;

%-----------------------

[Jiro Doke]

Sorry, there's a typo in my example. charcell inside the for-loop should read

charcell1{i}=sprintf(fmt, mtx(i));

% forgot the '1' after 'charcell'.

[urs (us) schwarz]

loop-equivalent for the well known siblings NUM2STR and NUM2CELL, eg,

x=0:2;
num2cell(num2str(x','%5.1d'),2)'
% ans = '0' '1' '2'

pointers to these genuine functions should be provided in the help section
us

[Jiro Doke]

There's a difference in the output using US's method. For example, try the following using my and Us's method:

mtx = [1 2 3];
fmt = '%4d';

Notice that num2str strips leading spaces. You need to choose a method based on what you want the code to do.