I have a very large list of integers representing data needed for a histogram that I'm going to plot using pylab. However, most of these values (85%-95%) are zero and I would like to remove them to reduce the amount of memory I'm using and save time when it comes to plotting the data. To do this, I'm trying to find the best way to remove all of the zero values and produce a list of indices of where the non-zero values used to be.
For example, if my original list is [0,0,1,2,1,0,0] I would like to produce the lists [1,2,1] (the non zero values) and [2,3,4] (indices of where the non-zero values used to be). Removing non-zero values is very easy but determining the indicies is where I'm having difficulty. Thanks in advance for any help -- http://mail.python.org/mailman/listinfo/python-list