histc problem

Hi, I have a matrix as follows:

I =

     1     1     1     8     8     1     2
     1     8     8     8     8     2     1
     1     8     8     8     2     1     1
     1     8     8     8     1     1     1
     2     2     2     1     1     1     1
     2     2     2     1     1     1     1

then the following code give me a error:

index= I==8; histc(index(:),1)

gives the follwing error.

??? Error using ==> histc First input must be non-sparse numeric array.

How to solve this?

Thanks

Answer 1

[Walter Roberson]

I'm not sure what you think you are going to accomplish with that, but

index = 0 + (I==8);
histc(index(:),1)

[Mohammad Golam Kibria]

your code give the proper output that i want.but why the following syntax is necessary:

index = 0 + (I==8);

[Mohammad Golam Kibria]

actually I have tow matrix I and I1.

I have some values having 1. and I1 is a binary matrix having

0 and 1. I need two know how many 1s are there in I1 where

the values of I have 1s. Is there any easy code