Count the number of equal and different occurrences in an array

Good Morning.

In case I have an array with 200 or more rows. In this matrix, I have 3 columns but I need to count the number of equal and different occurrences.

Example:

column 1 column 2 column 3

1 0 0

2 0 0

3 1 1

4 0 1

5 1 1

6 1 0

...

and so on. What I want is to compare column 2 with column 3 and return the number of occurrences as I say below.

What I intend is:

1 1 -> appears 2 times (in the example)

0 1 -> appears 1 time and so on (in the example)

1 0 -> appears 1 time and so on (in the example)

0 0 -> appears 2 times and so on (in the example)

Only this replicated by 200 or more lines..

Any idea?

I think it's something easy but I can't think of anything

Thanks

Answer 1

[Star Strider]

Use unique on the last two columns, then accumarray to sum the occurrences —

A = [1 0 0
     2 0 0
     3 1 1
     4 0 1
     5 1 1
     6 1 0];

[Au23,ia,ix] = unique(A(:,[2 3]), 'rows');
Tally = accumarray(ix,1);
Result = [Au23, Tally]

Result = 4×3

0 0 2 0 1 1 1 0 1 1 1 2

.

[PEDRO ALEXANDRE Fernandes]

Thank you so much!

Wonderfull day for you

[Star Strider]

As always, my pleasure!

You, too!

.