第一题（Windows）：

def my_ls(filename):    if os.path.isdir(filename):        filetype = '<DIR>'        size = '    '    else:        filetype = '    '        size = str(os.path.getsize(filename))    print(        time.strftime(            "%Y/%m/%d %H:%M\t", time.localtime(os.path.getmtime(filename))),        filetype,        '\t',        '%10s' % size,        ' ',        filename)if __name__ == '__main__':    for filename in ['.'] + ['..'] + os.listdir('.'):        my_ls(filename)

第二题（递归）：

def my_search(dirname, key):    for filename in os.listdir(dirname):        path = os.path.join(dirname, filename)        if os.path.isdir(path):            my_search(path, key)        if key in filename:            print(os.path.abspath(path))if __name__ == '__main__':    my_search('.', '.py')