How to perform element-wise tests on a vector in Mata

Question

Suppose I have a vector foo defined in Mata thus:

mata: foo = (1,2,1,3,1,4)

How do I perform an element-wise test on foo? For example, in R, if I define foo thus:

foo = c(1,2,1,3,1,4)

I can simply type:

foo == 1 

and I obtain as a result a vector of boolean values for the element-wise test == 1:

TRUE FALSE TRUE FALSE TRUE FALSE

which I can then assign or perform operations on (e.g. count up the number of TRUE or FALSE values).

I could, of course take several lines of code to loop over each element, but wonder if the language has an elegant syntax for this task already.

Answer 1

Use the colon (:) operator for element-by-element calculations.

mata

V = (1 \ 2 \ 3 \ 4)
V

V :== 1

end

See help [M-2] op_colon for details.