What is the function of find()

Can anyone help me understanding the below code?

 n_actions = find(reward(cs,:)>0); 

Where 'reward' is a matrix. For example,

reward = [1 2 3; 3 4 5; 5 6 7]; cs = 1;

Thank you

Answer 1

[Ameer Hamza]

reward = [1 2 3; 3 4 5; 5 6 7]; cs = 1;

Check the output of your code one part at a time

>> reward(cs,:)
ans =
     1     2     3

The above line output cs=1 row of matrix reward. Next we use compairson operator

>> reward(cs,:)>0
ans =
  1×3 logical array
   1   1   1

This line find which elements are greater than 0. As you can see, all of them are above zero so we get [1 1 1]. Next

>> find(reward(cs,:)>0)
ans =
     1     2     3

The find() function return the index of all elements that are non-zero.

For example,

>> find([1 2 0 1 0])
ans =
     1     2     4

It shows that element number 1, 2, and 4 are non-zero.

[Image Analyst]

An excellent, very thorough, and instructive answer! 😊 👍🏻

[Ameer Hamza]

Thanks Image Analyst :)

[feit feit]

Many thanks, Hamza!