Python读取CIFAR-10数据集教程

import numpy as np  
import os  
import cPickle as pickle  
import glob  
import matplotlib.pyplot as plt     
you_dir='C:\cifar-10-batches-py'
class_names_cifar10 = np.load(os.path.join(you_dir, "batches.meta"))  
#class_names_cifar100 = np.load(os.path.join(you_dir, "meta")) 
def one_hot(x, n):  
    """ 
    convert index representation to one-hot representation 
    """  
    x = np.array(x)  
    assert x.ndim == 1  
    return np.eye(n)[x]  
  
def _load_batch_cifar10(filename, dtype='float64'):  
    """ 
    load a batch in the CIFAR-10 format 
    """  
    path = os.path.join(you_dir, filename)  
    batch = np.load(path)  
    data = batch['data'] / 255.0 # scale between [0, 1]  
    labels = one_hot(batch['labels'], n=10) # convert labels to one-hot representation  
    return data.astype(dtype), labels.astype(dtype)  
  
  
def _grayscale(a):  
    print a.reshape(a.shape[0], 3, 32, 32).mean(1).reshape(a.shape[0], -1)  
    return a.reshape(a.shape[0], 3, 32, 32).mean(1).reshape(a.shape[0], -1)