[Julia usage] How to get 2D indexes from 1D index when accessing a 2D array?

[fedoroff]

Take a look at CartesianIndices:

x = rand((7, 10))
CI = CartesianIndices((7, 10))
for i in 1:length(x)
    r = CI[i][1]
    c = CI[i][2]
    @assert x[i] == x[r, c]
end