How to count how many numbers are prime in each column

I have a 100x10 matrix that goes from 1-1000 , and each set of hundreds is in its own column.

onethousand = reshape(1:1000, 100, 10)

I need to find how many prime numbers are in each column. I know that I have to use the function isprime, but I do not know how. Any suggestions?

Answer 1

[Akira Agata]

How about using isprime function?

sum(isprime(onethousand))

It returns:

>> sum(isprime(onethousand))
ans =
  25    21    16    16    17    14    16    14    15    14