How to add some symbols into a matrix ?

9 visualizzazioni (ultimi 30 giorni)
Niki
Niki il 30 Ago 2011
In fact , I have a Matrix like X =
0 5.2 4.8 28.8
0 0 1.0 33.8
0 0 0 33.4
0 0 0 0
I would like to create like this
0 5.2 4.8 28.8
NaN 0 1.08 33.8
NaN NaN 0 33.4
NaN NaN NaN 0
I wrote something like this, but it does not work very well. because I would like to keep the first column and first row zero value, the second column second row zero value and so on
[m,n]=size (X) for i=1:m; for j=1:n; if X(i,j)==0 X(i,j)= NaN ; end end end

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Daniel Shub
Daniel Shub il 30 Ago 2011
It depends on what you want to do with this matrix. If you just want it to be displayed nicely:
classdef partmat < double
methods
function obj = partmat(data)
if nargin < 1
data = [];
end
validateattributes(data, {'numeric'}, {'2d'})
obj = obj@double(data);
end
function disp(obj)
for irow = 1:size(obj, 1)
for icolumn = 1:size(obj, 2)
if ~isnan(obj(irow, icolumn))
x = num2str(obj(irow, icolumn));
else
x = '--';
end
fprintf(['\t', x]);
end
fprintf('\n');
end
end
end
end
Example:
>> x = partmat(magic(5))
x =
17 24 1 8 15
23 5 7 14 16
4 6 13 20 22
10 12 19 21 3
11 18 25 2 9
>> x(3) = nan
x =
17 24 1 8 15
23 5 7 14 16
-- 6 13 20 22
10 12 19 21 3
11 18 25 2 9
If you want to get even fancier you could overload subsassgn and allow notation like
x(5) = '--'
  3 Commenti
Daniel Shub
Daniel Shub il 30 Ago 2011
What version of MATLAB are you using? The code needs to be saved into a file called partmat.m.
Niki
Niki il 30 Ago 2011
I have all these versions 6.5 7.1 7.9 and 7.12

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Più risposte (1)

Andrei Bobrov
Andrei Bobrov il 30 Ago 2011
X(tril(true(size(X)),-1))=nan
add
X(bsxfun(@lt,1:4,(1:4)'))=nan
more
only for cell array
Xc = num2cell(X)
Xc(bsxfun(@lt,1:4,(1:4)'))={'-'}
  4 Commenti
Andrei Bobrov
Andrei Bobrov il 30 Ago 2011
I agree with Walter Robenson
Niki
Niki il 30 Ago 2011
In fact both andrei answer are very nice and useful,
Walter no, I do not want to prefix a number by "-",
I just wanted to put "-" instead zero when I copied the output into a xls file
However it seems that Andrei second comment works well .
I put another question , please also take a look at it

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