my_list = [3, 5, 1, 4, 2]
my_list.sort()
print (my_list)
#输出： [1, 2, 3, 4, 5]

my_list = [3, 5, 1, 4, 2]
result = sorted(my_list)
print (result)
#输出： [1, 2, 3, 4, 5]

my_dict = {"a":"1", "c":"3", "b":"2"}
result = sorted(my_dict)
print (result)
#输出: ['a', 'b', 'c']

student_tuples = [
    ('john', 'A', 15),
    ('jane', 'B', 12),
    ('dave', 'B', 10),
]
result = sorted(student_tuples, key=lambda student: student[2])
print (result)
#输出 [('dave', 'B', 10), ('jane', 'B', 12), ('john', 'A', 15)]

lambda student:student[2] 等价于
def f(student):
  return student[2]

my_dict = {"a":"2", "c":"5", "b":"1"}
result = sorted(my_dict)
print (result)
#默认对dict排序，不指定key参数,会默认对dict的key值进行比较排序
#result输出: ['a', 'b', 'c']
result2 = sorted(my_dict, key=lambda x:my_dict[x])
print (result2)
#指定key参数，根据dict的value排序
#result2输出:['b', 'a', 'c']

> sorted("This is a test string from Andrew".split(), key=str.lower)
['a', 'Andrew', 'from', 'is', 'string', 'test', 'This']

> student_tuples = [
...   ('john', 'A', 15),
...   ('jane', 'B', 12),
...   ('dave', 'B', 10),
... ]
> sorted(student_tuples, key=lambda student: student[2])  # sort by age
[('dave', 'B', 10), ('jane', 'B', 12), ('john', 'A', 15)]

> class Student:
...   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))
>
> student_objects = [
...   Student('john', 'A', 15),
...   Student('jane', 'B', 12),
...   Student('dave', 'B', 10),
... ]
> sorted(student_objects, key=lambda student: student.age)  # sort by age
[('dave', 'B', 10), ('jane', 'B', 12), ('john', 'A', 15)]