Equivalent of count_nonzero()

[Sergiy Radyakin]

Dear, All,

just wanted to confirm with you whether there exists a built-in function in Mata to calculate the equivalent of python's count_nonzero(), which reports the number (count) of the elements of a matrix that are different from zero.

No problem implementing this with nested loops. Just looking for a built-in function if available.

Thank you, Sergiy

[Mike Lacy]

Would count0 = sum(A:!=0) work for you?

[Sergiy Radyakin]

Yes, Mike, thank you very much!
This is perfect!

mata
A=1,2,0,0,7 \ 2,0,0,1,0
sum(A:!=0)
sum(A[1,.]:!=0)
sum(A[2,.]:!=0)
end

. mata
------------------------------------------------- mata (type end to exit) ------------------------------------------------------------------------------------------------
: A=1,2,0,0,7 \ 2,0,0,1,0

: sum(A:!=0)
  5

: sum(A[1,.]:!=0)
  3

: sum(A[2,.]:!=0)
  2

: end