datasets_fetch_lif_people源码阅读以及代码运行错误问题

1.datasets.fetch_lfw_people源码阅读笔记

def fetch_lfw_people(data_home=None, funneled=True, resize=0.5,
                     min_faces_per_person=0, color=False,
                     slice_=(slice(70, 195), slice(78, 172)),
                     download_if_missing=True):
    """Loader for the Labeled Faces in the Wild (LFW) people dataset

    This dataset is a collection of JPEG pictures of famous people
    collected on the internet, all details are available on the
    official website:

        http://vis-www.cs.umass.edu/lfw/

    Each picture is centered on a single face. Each pixel of each channel
    (color in RGB) is encoded by a float in range 0.0 - 1.0.

    The task is called Face Recognition (or Identification): given the
    picture of a face, find the name of the person given a training set
    (gallery).

    The original images are 250 x 250 pixels, but the default slice and resize
    arguments reduce them to 62 x 74.

    Parameters
    ----------
    data_home : optional, default: None
        Specify another download and cache folder for the datasets. By default
        all scikit learn data is stored in '~/scikit_learn_data' subfolders.

    funneled : boolean, optional, default: True
        Download and use the funneled variant of the dataset.

    resize : float, optional, default 0.5
        Ratio used to resize the each face picture.

    min_faces_per_person : int, optional, default None
        The extracted dataset will only retain pictures of people that have at
        least `min_faces_per_person` different pictures.

    color : boolean, optional, default False
        Keep the 3 RGB channels instead of averaging them to a single
        gray level channel. If color is True the shape of the data has
        one more dimension than the shape with color = False.

    slice_ : optional
        Provide a custom 2D slice (height, width) to extract the
        'interesting' part of the jpeg files and avoid use statistical
        correlation from the background

    download_if_missing : optional, True by default
        If False, raise a IOError if the data is not locally available
        instead of trying to download the data from the source site.

    Returns
    -------
    dataset : dict-like object with the following attributes:

    dataset.data : numpy array of shape (13233, 2914)
        Each row corresponds to a ravelled face image of original size 62 x 47
        pixels. Changing the ``slice_`` or resize parameters will change the
        shape of the output.

    dataset.images : numpy array of shape (13233, 62, 47)
        Each row is a face image corresponding to one of the 5749 people in
        the dataset. Changing the ``slice_`` or resize parameters will change
        the shape of the output.

    dataset.target : numpy array of shape (13233,)
        Labels associated to each face image. Those labels range from 0-5748
        and correspond to the person IDs.

    dataset.DESCR : string
        Description of the Labeled Faces in the Wild (LFW) dataset.
    """