Method __init__

tensorpack/dataflow/common.py:338–348

Args: ds (DataFlow): input DataFlow which produces either list or dict. func (TYPE -> TYPE|None): takes ``dp[index]``, returns a new value for ``dp[index]``. Return None to discard/skip this datapoint. index (int or str): index or key of t

(self, ds, func, index=0)

            ds = MapDataComponent(ds, lambda img: img * 255, 0)  # map the 0th component
    """
    def __init__(self, ds, func, index=0):
        """
        Args:
            ds (DataFlow): input DataFlow which produces either list or dict.
            func (TYPE -> TYPE|None): takes ``dp[index]``, returns a new value for ``dp[index]``.
                Return None to discard/skip this datapoint.
            index (int or str): index or key of the component.
        """
        self._index = index
        self._func = func
        super(MapDataComponent, self).__init__(ds, self._mapper)

    def _mapper(self, dp):
        r = self._func(dp[self._index])