CPU 密集型任务和 IO 密集型任务分别选择多进程multiprocessing.Pool.map

和多线程库multiprocessing.dummy.Pool.map

import os import PIL from multiprocessing import Pool from PIL import ImageSIZE = (75,75)SAVE_DIRECTORY = 'thumbs'def get_image_paths(folder):    return (os.path.join(folder, f)             for f in os.listdir(folder)             if 'jpeg' in f)def create_thumbnail(filename):     im = Image.open(filename)    im.thumbnail(SIZE, Image.ANTIALIAS)    base, fname = os.path.split(filename)     save_path = os.path.join(base, SAVE_DIRECTORY, fname)    im.save(save_path)if __name__ == '__main__':    folder = os.path.abspath(        '11_18_2013_R000_IQM_Big_Sur_Mon__e10d1958e7b766c3e840')    os.mkdir(os.path.join(folder, SAVE_DIRECTORY))    images = get_image_paths(folder)    pool = Pool()    pool.map(creat_thumbnail, images)    pool.close()    pool.join()