Method key_iterator

monai/transforms/transform.py:468–489

Iterate across keys and optionally extra iterables. If key is missing, exception is raised if `allow_missing_keys==False` (default). If `allow_missing_keys==True`, key is skipped. Args: data: data that the transform will be applied to extra_iterables

(self, data: Mapping[Hashable, Any], *extra_iterables: Iterable | None)

        raise NotImplementedError(f"Subclass {self.__class__.__name__} must implement this method.")

    def key_iterator(self, data: Mapping[Hashable, Any], *extra_iterables: Iterable | None) -> Generator:
        """
        Iterate across keys and optionally extra iterables. If key is missing, exception is raised if
        `allow_missing_keys==False` (default). If `allow_missing_keys==True`, key is skipped.

        Args:
            data: data that the transform will be applied to
            extra_iterables: anything else to be iterated through
        """
        # if no extra iterables given, create a dummy list of Nones
        ex_iters = extra_iterables or [[None] * len(self.keys)]

        # loop over keys and any extra iterables
        _ex_iters: list[Any]
        for key, *_ex_iters in zip(self.keys, *ex_iters):
            # all normal, yield (what we yield depends on whether extra iterables were given)
            if key in data:
                yield (key,) + tuple(_ex_iters) if extra_iterables else key
            elif not self.allow_missing_keys:
                raise KeyError(
                    f"Key `{key}` of transform `{self.__class__.__name__}` was missing in the data and allow_missing_keys==False."
                )

    def first_key(self, data: dict[Hashable, Any]):
        """