Project Euler Problem 11
If LIST were a two-dimensional numpy array, you could use 
LIST[i,:] to get the ith row,
LIST[:,i] to get the ith column,
numpy.diagonal(LIST, i) to get the diagonal i places above the main diagonal (where -17 &lt; i and i &lt; 17 in order to restrict to diagonals containing at least four cells),
and numpy.diagonal(numpy.flipud(LIST), i) to get the left diagonal i places below the main left diagonal.

Each of the four operations in the previous paragraph returns either an array or an array view.
Every set of four numbers that you wanted to look at will show up as four consecutive values in one of these arrays or array views,
so you just need to look at each product of four consecutive integers
within each array or array view.