How do I convert a stereo wav to mono

Question

If I already have the wav data in two arrays (left channel & right channel) how does one go about to converting them to a single mono array?

Is there a function f so that Mono[x] = f(L[x],R[x]) ?

Answer 1

Mixing is the average of the two channels.

f_mono = function(l, r) {  
   return (l + r) / 2;
}

Answer 2

Just take an average of both value.