我是 python 的新手，我正在阅读 python 文档和给定的示例 http://docs.python.org/2/howto/sorting.html#key-functions我被卡住了，我不明白它是如何工作的。
我正在使用 eclipse Pydev 来运行这段代码..
class Student:
student_object = [
('john', 'a', 15),
('as', 'C', 12),
('dave', 'B', 10)
]
def __init__(self, name, grade, age):
self.name = name
self.grade = grade
self.age = age
def __repr__(self):
return repr((self.name, self.grade, self.age))
print sorted(Student.student_object, key=lambda Student: Student.age)
错误
Traceback (most recent call last):
File "C:\Users\user1\workspace\demPython\src\ru.py", line 26, in <module>
print sorted(Student.student_object, key=lambda Student: Student.age)
File "C:\Users\user1\workspace\demPython\src\ru.py", line 26, in <lambda>
print sorted(Student.student_object, key=lambda Student: Student.age)
AttributeError: 'tuple' object has no attribute 'age'
类和方法在 python 中是如何工作的？为什么这段代码不起作用？？
编辑
But i changein last line and replace with given line
print sorted(Student.student_object, key=lambda student: student[0])
它正在工作并给我输出 [('as', 'C', 12), ('dave', 'B', 10), ('john', 'a', 15)]
请您参考如下方法:
它不起作用，因为 student_object 中的项目不是您的 Student 类的实例，它们只是普通的元组。这就是错误是 'tuple' object has no attribute 'age' 的原因。
您需要先创建学生对象:
class Student(object):
def __init__(self, name, grade, age):
self.name = name
self.grade = grade
self.age = age
def __repr__(self):
return '{0.name} {0.grade} {0.age}'.format(self)
students = [Student('john','a',15), Student('as','C',12), Student('dave','B',10)]
print sorted(students, key=lambda x: x.age)
