double array of 0's and 1's conversion help

I have an array of 0's and 1's

Im trying to convert the 0's to nans and 1's to another value.

A(find(A==1)=256; %this part works
A(find(A==0)=NaN; %this part doesn't

when i try to replace the 0's, it replaces everything in the array with NaN, even though find(A==0) does return only the indices of where that array has a 0 value.

is there technical thing I'm missing here?

Answer 1

[Walter Roberson]

A(A==1) = 256;
A(A==0) = NaN;

If you want to live a life of confusion, and you only have 0 and 1s in the matrix,

A = A ./ A * 256;

[the cyclist]

Walter, I recognize that your syntax avoids the unnecessary find(), but what's the use case in which your syntax works, but David's doesn't? I'm puzzled.

[Tom]

He may have left the bracket off like in the question?

[Walter Roberson]

Reduces the steps that can go wrong ?

[David C]

sorry, i just forgot to put the brackets in while typing, i have them in my actual code

Answer 2

[David C]

just tried

A(A==1) = 256;
A(A==0) = NaN;

and the same thing happened. The A==1 part worked, but as soon as it tried to logical index the ones that were 0, it replaced everything with NaN

[Sean de Wolski]

What happens if you run this:

A = double(rand(10)>0.5);

A(A==1) = 256;

A(A==0) = NaN;

A

[Walter Roberson]

Try breaking it down and do some experiments to see which step is going wrong:

A

T = A == 0

B = A;

A(T) = NaN

B(1) = NaN

C = rand(size(A));

C(T) = NaN