Findnearest function?

General Usage
5

Like @cormullion, I’ve had need for such a function many times, and here is my personal solution for it. Unlike @Dan’s version, this doesn’t care about ties and returns just a single index. Also, as it works on sorted arrays, the function name should be searchsortednearest to be consistent with Julia’s function names (I would expect findnearest to work on any array).

function searchsortednearest(a,x)
   idx = searchsortedfirst(a,x)
   if (idx==1); return idx; end
   if (idx>length(a)); return length(a); end
   if (a[idx]==x); return idx; end
   if (abs(a[idx]-x) < abs(a[idx-1]-x))
      return idx
   else
      return idx-1
   end
end
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