[julia-users] Stepping Average

[paul analyst]

I have meny lonng vectors (like a)and need avg for intervals (f.e. 100 ) in 
second new vecotr (b)

julia> a=rand(10^7);

julia> b=zeros(a);

julia> tic();for i in  [1:100:10^7;]
       b[i:i+99]=mean(a[i:i+99])
      end;toc()
elapsed time: 0.138522318 seconds
0.138522318

Is shorter way to compute this ?
Paul