Counting certain values from an array

Suppose we have an array r=(2,2,2) filled with zeros and ones. How to count up how many zeros and how many ones do we have?

Answer 1

[Image Analyst]

Try this:

numOnes = sum(r(:))
numZeros = numel(r) - numOnes

[Vadim Tambovtsev]

No, my array in more complicated. Array (m,n,k), contans "a" and "b" values. How many "a" and "b" are there?

[Image Analyst]

You could have sped this along by two hours by saying that first instead of saying the array is "filled with zeros and ones". So to count the number of a's and b's:

numA = length(find(r==a));
numB = length(find(r==b));

There are other ways, but this is fairly simple and compact.

[Vadim Tambovtsev]

quality control:

dd=[ 3 7; 4 5]
num7=sum(find(dd==7))
output:
num7= 3

Why is it 3? isn't it supposed to be 1, because there is 1 "7" in the array?

[Image Analyst]

Use length() instead of sum().