On Fri, 25 May 2018 15:30:36 +1000, Cameron Simpson wrote: > So, how to various forms of multidimensional lists play out as code?
With my suggestion, we get: x = [0]**3 # one-dimensional y = [[0]**3]**3 # two-dimensional z = [[[0]**3]**3]**3 # three-dimensional Or there's MRAB's suggestion of using @ instead of the ** operator. The one-dimensional case can be optimized by using regular * replication instead of ** duplication, but that's an optimization for immutable objects. Its pretty much harmless to write ** instead of * for the common case of a list filled with immutable ints or None. Here's a subclass that implements a simple version of this for testing: class ML(list): def __pow__(self, other): import copy L = [] for i in range(other): L.extend(copy.deepcopy(obj) for obj in self) return ML(L) And in use to generate a 3-D list: py> z = ML([ML([ML([0])**3])**3])**3 py> z[0][0][0] = 1 py> z[1][1][1] = 2 py> z[2][2][2] = 3 py> z [[[1, 0, 0], [0, 0, 0], [0, 0, 0]], [[0, 0, 0], [0, 2, 0], [0, 0, 0]], [[0, 0, 0], [0, 0, 0], [0, 0, 3]]] The repeated calls to ML() are ugly and are only there because the [] syntax creates ordinary lists, not my subclass. -- Steve -- https://mail.python.org/mailman/listinfo/python-list