Python – properties of ctypes.py_object

properties of ctypes.py_object… here is a solution to the problem.

properties of ctypes.py_object

I’m trying to create a python array but have the following code issue

def __init__(self, size):
    assert size>0, "Array size must be > 0"
    self._size = size
    # Create the array structure using the ctypes module.

arraytype = ctypes.py_object * size
    self._elements = arraytype()

In initialization, it creates an array using ctypes, the last two lines I don’t quite understand. I tried changing them to one line

self._elements = ctypes.py_object() * size

But it doesn’t work and gives me the error

TypeError: unsupported operand type(s) for *: 'py_object' and 'int'

Can anyone help me explain?


  • ctypes.py_object is a type
  • ctypes.py_object * size is a type
  • ctypes.py_object() is an instance of a type

What you have to do is first get the ctypes.py_object * size type and then instantiate it:

self._elements = (ctypes.py_object * size)()

While you might want to use a Python list, I’m not sure if you need a ctypes array. Example:

self._elements = [None] * size

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