Compare two columns under 3 conditions

Hi,

I an array (phases) with two vector of the same lenght. I need to compare the two vectors under the following conditios:

phases(:,1) phases(:, 2)

1................................. 2

1................................. 2

1................................. 2

2................................. 2

2................................. 2

2................................. 1

2................................. 1

2................................. 1

2................................. 1

1................................. 1

1................................. 1

1................................. 1

condition 1: I want to know the number of times phases(:,1) and phases(:, 2) are both 2 in the same row. In this case, there are 2 times.

condition 2: I want to know the number of times phases(:, 2) is equals to 2 when phases(:,1) is equals to 1 in the same row. In this case, there are 3 times.

condition 3: I want to know the number of times phases(:, 1) is equals to 2 when phases(:, 2) is equals to 1 in the same row. In this case, there are 4 times.

Thank you!

[madhan ravi]

your 2nd & 3rd conditions are the same?

[Francisco Anaya]

yes, they are same...

following your example below, then it should be....?

nnz(phases(:,2) == 2 & phases(:,2) == 2)

nnz(phases(:,1) == 1 & phases(:,2) == 2)

nnz(phases(:,1) == 2 & phases(:,2) == 1)

[Francisco Anaya]

it works only for condition 2 and 3...

phases= [1 1 1 2 2 2 2 2 2 1 1 1; 2 2 2 2 2 1 1 1 1 1 1 1]';

>> nnz(phases(:,2) == 2 & phases(:,2) == 2)

ans =

5

>> nnz(phases(:,1) == 1 & phases(:,2) == 2)

ans =

3

>> nnz(phases(:,1) == 2 & phases(:,2) == 1)

ans =

4

Answer 1

[Shunichi Kusano]

The following code counts the number of rows which meet the condition 2.

nnz(phases(:,2) == 2 & phases(:,1) == 1)

hope this helps.