Class DeleteItemsd

monai/transforms/utility/dictionary.py:671–706

Delete specified items from data dictionary to release memory. It will remove the key-values and copy the others to construct a new dictionary.

class DeleteItemsd(MapTransform):
    """
    Delete specified items from data dictionary to release memory.
    It will remove the key-values and copy the others to construct a new dictionary.
    """

    backend = [TransformBackends.TORCH, TransformBackends.NUMPY]

    def __init__(self, keys: KeysCollection, sep: str = ".", use_re: Sequence[bool] | bool = False) -> None:
        """
        Args:
            keys: keys of the corresponding items to delete, can be "A{sep}B{sep}C"
                to delete key `C` in nested dictionary, `C` can be regular expression.
                See also: :py:class:`monai.transforms.compose.MapTransform`
            sep: the separator tag to define nested dictionary keys, default to ".".
            use_re: whether the specified key is a regular expression, it also can be
                a list of bool values, mapping them to `keys`.
        """
        super().__init__(keys)
        self.sep = sep
        self.use_re = ensure_tuple_rep(use_re, len(self.keys))

    def __call__(self, data):

        def _delete_item(keys, d, use_re: bool = False):
            key = keys[0]
            if len(keys) > 1:
                d[key] = _delete_item(keys[1:], d[key], use_re)
                return d
            return {k: v for k, v in d.items() if (use_re and not re.search(key, f"{k}")) or (not use_re and k != key)}

        d = dict(data)
        for key, use_re in zip(cast(Sequence[str], self.keys), self.use_re):
            d = _delete_item(key.split(self.sep), d, use_re)

        return d


class SelectItemsd(MapTransform):