How do you make class to iterate by its internal numpy array : Just idea which does not work :
class ABC:
def __init__(self):
self.ary = np.zeros(50)
def __iter__(self): return np.nditer(self.ary)
def next(self): ...??..
Also how to make assignment work too :
abc = ABC()
abc[5] = 12
abc[7:9] 0
From documentation,
iterator.__next__():
Return the next item from the container. If there are no further items, raise the StopIteration exception. This method corresponds to the tp_iternext slot of the type structure for Python objects in the Python/C API.
For setting and getting values for container class, you need to implement __getitem__ and __setitem__.
For your sample code
class ABC():
def __init__(self):
self.ary = np.zeros(50)
self.index = self.ary.shape[0]
def __iter__(self):
return np.nditer(self.ary)
def next(self):
if self.index == 0:
raise StopIteration
self.index = self.index - 1
return self.data[self.index]
def _check_indx(self, idx):
if abs(idx) >= self.ary.shape[0]:
raise IndexError(f"Invalid Index {idx} for array with shape {self.ary.shape}")
def __setitem__(self, idx, value):
self._check_indx(idx)
self.ary[idx] = value
def __getitem__(self, idx):
self._check_indx(idx)
return self.ary[idx]
return np.diter(self.ary) in __iter__(self):, If you are planning to use this for 1-d array, you can change the return statement to return iter(self.ary) which will give the expected behaviour. For, Multi-dimensional cases np.diter would be better choice
next. Your class should work, so if it isn't working, you need to be specific about what doesn't work. "It doesn't work" isn't an adequate problem description. To make a class iterable you need to define__iter__. You only define__next__(note, it is__next__notnextin Python 3) only if you want your class to be an iterator, in which case,__iter__must returnself. You don't want to define an iterator, I think, but an iterable. Which you have. As to item-based assignment, please, also, avoid asking multiple questions.nditer. It's too difficult to use right, and doesn't offer any speed benefits.list?