Convert logical variable into integer number

Question

Guilherme Roberto 2016-3-8

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https://ww2.mathworks.cn/matlabcentral/answers/272096-convert-logical-variable-into-integer-number

回答： Marcelo Moraes 2022-1-10

Hi! I think my problem is very simple. I have some boolean expressions in my code, which the results will always be 1 or 0 (true or false). Here are some examples:

data=data+(-1*(~mat(i)&&mat(j)&&mat(k)))||(~mat(i)&&~mat(j));

or

data=data+(~mat(i));

I have to convert these logicals 1s and 0s to int values. I've tried using abs() but it is not working.

Btw, I'm on R2015b.

I appreciate the help.

Thanks!

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Answer 1

Ced 2016-3-8

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在 MATLAB Online 中打开

You can usually use logicals and numerical values interchangeably in matlab (for most operations), no need to convert them. But If you do, you can cast them e.g. using int8

a = logical(0); % a is a logical
b = a;          % b is a logical
c = int8(a);    % c is an int8

The same goes for other datatypes (int16, int32, double, ... ), see datatypes for details.

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Jim Morgenstern 2017-3-30

Actually this did not work for me ... which may be a bug in Matlab.

I have a logical array: E = uint8(zeros( ..., )); vcl = edge (A, 'canny', ...); vv = uint8(vcl); E = E + uint8(vcl);

when i do imtool(vcl), i see the pixels with edges. when i do imtool(E) it is all zero. and also imtool(vv) is all zero. I changed uint8 to double and it works correctly. possible bug?

Stephen23 2021-12-21

编辑：Stephen23 2021-12-21

"I changed uint8 to double and it works correctly. possible bug?"

Not at all. MATLAB assumes that UINT8 image data ranges from 0-255 (i.e. the entire 8-bit range) whereas DOUBLE image data ranges from 0-1 (i.e. normalized). This is clearly explained in the MATLAB documentation:

https://www.mathworks.com/help/images/image-types-in-the-toolbox.html

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