Change numpy array indexes (not values)-CodePudding

I have a numpy array, and i want see if it's possible to modify the index values (not the array values) with a custom sequence of numbers.

Let's say the array lengh is 10, it's possible to change the indexes so instead of accessing it's elements with the indexes 0-9 it can be accesed with.. let's say.. 50-59?

Basically like changing the rownames/colnames but in a np array instead of a pandas df.

CodePudding user response：

Not sure if there is ever a need for it and I'm sure there are other ways but one way would be to create a class for it. Working on your example of 50-59:

class UnnaturalList(list):
    def __getitem__(self, index):
        if type(index) == int and index > 0:
            index -= 50
        if type(index) == slice:
            start, stop = index.start, index.stop
            if start and start > 0:
                start -= 50
            if stop and stop > 0:
                stop -= 50
            index = slice(start, stop, index.step)
        return super().__getitem__(index)

    def __setitem__(self, index, val):
        super().__setitem__(index - 50, val)

Then you can create a list with this class and use indexing and slicing

a_list = UnnaturalList(range(1,6))
a_list --> [1,2,3,4,5]
a_list[50] --> 1
a_list[51] --> 2
a_list[50:53] --> [1,2,3]

I would think there is a way to do something similar for arrays, or something cleaner, but this is one method for you.