Python-打印特定對象列表屬性

Question

如何從對象列表中打印特定的對象屬性。 我以為可以提供特定的列表索引，但嘗試嘗試時會出現以下錯誤： AttributeError: 'list' object has no attribute 'grade'

class tests():

    def __init__(self,grade):
         self.grade = grade


test_list = []

for x in range(1,6):
    test_object = tests(x)
    test_list.append(test_object)


print (test_list[1].grade)

Answer 1

您這里有一些錯誤。

class tests():

    def __init__(self,grade):
         self.grade = grade


test_list = []

for x in range(1,6):
    test_object = tests(x)
    test_list.append(test_object)

list_a = [5,3,2,1,4]

# THIS LINE BELOW IS THE PROBLEM    
for x in [test_list]:
    # in this line below X = test_list and indeed test_list.grade doesn't make sense.
    test_list.append(sorted(x.grade,key=list_a.index))


print (test_list[1].grade)