Python Forum

I am trying to implement getters and setters in a class using a numpy array as the base instance value, but I am not able to pass an array index argument to the getter function (and probably not to the setter function, but it never gets that far).

The code is as follows:

import numpy as np

class Matrix:
    def __init__(self, msize):
        self.msize = msize
        self.mvalues = np.full([msize + 2, msize + 2, msize + 2], -1,
                               dtype=np.int32)
        self.mvalues[1:-1, 1:-1, 1:-1] = 0
        self.visited = np.zeros([msize + 2, msize + 2, msize + 2],
                                dtype=np.int32)

    @property
    def visits(self, coord):
        return self.visited[coord[0], coord[1], coord[2]]

    @visits.setter
    def incr_visits(self, coord, incr):
        self.visited[coord[0], coord[1], coord[2]] += incr


def Coord(x, y, z):
    return np.full([3,], (x, y, z), dtype=np.int32)

mycoord = Coord(1, 2, 3)
print("mycoord={}".format(mycoord))

mygal = Matrix(10)
print("Before set:{}".format(mygal.visits(mycoord)))

mygal.incr_visits(mycoord, 10)
print("After  set:{}".format(mygal.visits(mycoord)))

And this is the output I get:

Output:
mycoord=[1 2 3]
Traceback (most recent call last):
  File "C:\Users\MyUser\Test\clstest4.py", line 28, in <module>
    print("Before set:{}".format(mygal.visits(mycoord)))
TypeError: visits() missing 1 required positional argument: 'coord'

Please tell me what I am doing wrong here.

Peter

Not sure what are you trying to achieve, but please execute the following code:

import numpy as np


class Matrix:
    def __init__(self, msize):
        self.msize = msize
        self.mvalues = np.full([msize + 2, msize + 2, msize + 2], -1,
                               dtype=np.int32)
        self.mvalues[1:-1, 1:-1, 1:-1] = 0
        self.visited = np.zeros([msize + 2, msize + 2, msize + 2],
                                dtype=np.int32)

    @property
    def visits(self, coord):
        return self.visited[coord[0], coord[1], coord[2]]

    @visits.setter
    def incr_visits(self, coord, incr):
        self.visited[coord[0], coord[1], coord[2]] += incr


def Coord(x, y, z):
    return np.full([3, ], (x, y, z), dtype=np.int32)


mycoord = Coord(1, 2, 3)
print("mycoord={}".format(mycoord))
mygal = Matrix(10)
print('This is what is created inside Matrix object: ')
print(type(mygal.visited))
print(mygal.visited)
print('This is how mycoord looks like: ')
print(type(mycoord))
print(mycoord)

Attribute visited is very strange to me.

I added your code and reduced the Matrix size from 10 to to 3 so output would be shorter. Below is the output.

The arrays in the class and the Coord() value are NUMPY arrays, not regular python arrays.

My question is still whether I am off-base in thinking that property methods and getter/setters can take additional positional parameters as in my example.

Peter

Output:
mycoord=[1 2 3]
This is what is created inside Matrix object:
<class 'numpy.ndarray'>
[[[0 0 0 0 0]
  [0 0 0 0 0]
  [0 0 0 0 0]
  [0 0 0 0 0]
  [0 0 0 0 0]]

 [[0 0 0 0 0]
  [0 0 0 0 0]
  [0 0 0 0 0]
  [0 0 0 0 0]
  [0 0 0 0 0]]

 [[0 0 0 0 0]
  [0 0 0 0 0]
  [0 0 0 0 0]
  [0 0 0 0 0]
  [0 0 0 0 0]]

 [[0 0 0 0 0]
  [0 0 0 0 0]
  [0 0 0 0 0]
  [0 0 0 0 0]
  [0 0 0 0 0]]

 [[0 0 0 0 0]
  [0 0 0 0 0]
  [0 0 0 0 0]
  [0 0 0 0 0]
  [0 0 0 0 0]]]
This is how mycoord looks like:
<class 'numpy.ndarray'>
[1 2 3]