Question

Bellow是我目前的代码，我对Python很陌生。我正在尝试创建一个Photo实例列表，其中每个Photo实例使用tups_list中每个元组的数据。并将该列表保存在变量photo_insts中。目前我没有收到错误，字面上，当我尝试运行该文件时，终端中没有发生任何事情。

photo_insts = []
tups_list = [("Portrait 2","Gordon Parks",["chicago", "society"]),("Children in School","Dorothea Lange",["children","school","1930s"]),("Airplanes","Margaret Bourke-White",["war","sky","landscape"])]
class Photo2(object):
    def __init__(self, title_str, photo_by,tags_list):
        self.title = title_str
        self.artist = photo_by
        self.tags = tags_list
        for i in tups_list:
            photo_tuple = (i[0],i[1],i[2])
            photo_insts.append(photo_tuple)
            print i

以下是运行以检查不同值的测试：

class Phototest(unittest.TestCase):
    def test_photo_insts1(self):
        self.assertEqual(type(photo_insts),type([]))
    def test_photo_insts2(self):
        self.assertEqual(type(photo_insts[0]),type(Photo("Photo2","Photo Student",["multiple","tags"])))
    def test_photo_insts3(self):
        self.assertEqual([x.title for x in photo_insts],["Portrait 2", "Children in School", "Airplanes"])
    def test_photo_insts4(self):
        self.assertEqual([x.artist for x in photo_insts],["Gordon Parks","Dorothea Lange","Margaret Bourke-White"])
    def test_photo_insts5(self):
        self.assertEqual([x.tags for x in photo_insts],[["chicago","society"],["children", "school","1930s"],["war","sky","landscape"]])

Answer 1

我猜这是一个错字：

photo_tuple = (i[0],i[1],i[2])

=＆GT;

photo_tuple = Photo2 (i[0],i[1],i[2])

在创建实例__init__时调用函数Photo2。如果你在函数Photo2 ()中调用__init__，那么你会得到一个递归！

=＆GT;代码应如下所示：

class Photo2(object):
    def __init__(self, title_str, photo_by, tags_list):
        self.title  = title_str
        self.artist = photo_by
        self.tags   = tags_list
# end class
tups_list = [
     ("Portrait 2","Gordon Parks",["chicago", "society"])
    ,("Children in School","Dorothea Lange",["children","school","1930s"])
    ,("Airplanes","Margaret Bourke-White",["war","sky","landscape"])
    ]
photo_insts = []
for i in tups_list :
    photo_tuple = Photo2 (i[0],i[1],i[2])
    photo_insts.append(photo_tuple)
    print i[0]
for p in photo_insts :
    print repr (p)

控制台输出：

Portrait 2
Children in School
Airplanes
<__main__.Photo2 object at 0xb7082cac>
<__main__.Photo2 object at 0xb7082ccc>
<__main__.Photo2 object at 0xb7082cec>

变量实例列表

1 个答案: