Question

I have a very large NumPy array: a = np.array. From this array I want to get the min, max and average which can be easily done with np.min(a), np.max(a) and np.mean(a).

However, I want also to have the min, max and average of a portion (begin part or end part) of this array. Are there some functions for this without creating a new array/list (because that would really result in a bad performance penalty)?

Answer 1

All arrays generated by basic slicing are always views of the original array.

http://docs.scipy.org/doc/numpy/reference/arrays.indexing.html

So, yes, just use slices.