On May 27, 11:19 am, Peter Otten <__pete...@web.de> wrote: > colin.hank...@touit.com wrote: > > Disclaimer: I'm learning python and would like to use it in a > > project. > > > The project will have many large matricies. In one particular instance > > I need to reference a smaller submatrix of the larger matrix. I don't > > want to create a new copy or even change any of the values, I just > > want to quickly and easily be able to look at this sub matrix. > > > So I am using lists of lists for the matricies (I am also playing with > > NumPy) and is there anyway to create a pointer to an offset in a > > list? > > > I know you can have A = B = [] which would be the same. > > > And I know I can simply do a B[x + offset to submatrix]. > > > But I was hoping there may be a way to just have a pointer? Or is > > there another more efficient method to do this in python? > > What you describe is what numpy does: > > """ > Therefore, a regular indexing expression on an ndarray can always produce an > ndarray object without copying any data. This is sometimes referred to as > the “view” feature of array indexing, and one can see that it is enabled by > the use of striding information in the underlying ndarray object. The > greatest benefit of this feature is that it allows indexing to be done > very rapidly and without exploding memory usage (because no copies of the > data are made). > """- Hide quoted text - > > - Show quoted text -
Thank you. That certainly did the trick! -- http://mail.python.org/mailman/listinfo/python-list
