Find a certain cell in a cell array?

Question

Pooya Ferdosipour 2015-8-23

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编辑： Pooya Ferdosipour 2015-8-24

Hello all,

Suppose we have a a cell array 3x3 there is one matrices in each cell. we already know that if A=[1 0 3 49 5 6 7] then A(4)=49 and also we can easily find the location of 49 in matrices by using find(A==49). But it does not work for cell array! for example if I assume a cell array : I= {[1,2] [2,3] [4,5] ; [6,6] [0.8,8] [2,3] ; [1.1,4] [1,1] [2,2] }

I can not say find I ==[0.8,8] and the answer gives me "5" (the 5th cell). How can I find the locations for a certain value of cell like [0.8,8]?

All the best,

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Answer 1

Azzi Abdelmalek 2015-8-23

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I={  [1,2]   [2,3]   [4,5] ;
[6,6]   [0.8,8] [2,3] ;
[1.1,4] [1,1]   [2,2] }
[ii,jj]=find(cellfun(@(x) isequal(x,[0.8,8]),I))

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Pooya Ferdosipour 2015-8-24

编辑：Pooya Ferdosipour 2015-8-24

thanks alot :) (LIKE)

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Answer 2

Walter Roberson 2015-8-23

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find(cellfun(@(C) isequal(C, [0.8,8]), I)

However, floating point numbers are seldom equal even when they look like they are. 0.8 cannot be represented exactly in binary floating point (just like 1/3 cannot be represented exactly as a finite decimal), and the exact value stored is going to depend on the exact way that the value was calculated.

http://www.mathworks.com/matlabcentral/answers/97069-how-can-i-compare-numbers-for-equality-within-a-tolerance-in-matlab-8-0-r2012b

http://www.mathworks.com/help/matlab/ref/ismembertol.html