我有一个单向链表，其中数据是我创建的一个自定义对象，名为“Patient”，我根据“Patient.points”对链表进行排序。
但是，如果被比较的两个患者具有相同的点数，我还想按“Patient.bmi”对列表进行排序，作为辅助过滤器。
我希望通过 BMI 过滤器对患者进行排序的方式是让 bmi 最差的患者按升序排列。我有四种“状况”，“肥胖、超重、体重不足和正常”。我希望肥胖、超重和正常按降序排列，体重不足按升序排列。
这是我的链表：
class Node:
def __init__(self):
self.data = None
self.next = None
class LinkedList:
def __init__(self):
self.head = None
def addNode(self, data):
curr = self.head
if curr is None:
n = Node()
n.data = data
self.head = n
return
if curr.data.points == data.points and curr.data.condition == 'underweight':
if curr.data.bmi > data.bmi:
n = Node()
n.data = data
n.next = curr
self.head = n
return
elif curr.data.points == data.points and curr.data.condition != 'underweight':
if curr.data.bmi < data.bmi:
n = Node()
n.data = data
n.next = curr
self.head = n
return
if curr.data.points < data.points:
n = Node()
n.data = data
n.next = curr
self.head = n
return
while curr.next is not None:
if curr.next.data.points < data.points:
break
curr = curr.next
n = Node()
n.data = data
n.next = curr.next
curr.next = n
return
def __str__(self):
data = []
curr = self.head
while curr is not None:
data.append(curr.data)
curr = curr.next
return "[%s]" %(', '.join(str(i) for i in data))
def __repr__(self):
return self.__str__()
这是返回的数据：
Paitent name: BDF237 age: 79 Years 2 Months 14 Days BMI: 37.960398071201396 weight classification: obese
Paitent name: ABE127 age: 20 Years 6 Months 20 Days BMI: 34.54054238911118 weight classification: obese
Paitent name: ABD721 age: 73 Years 4 Months 25 Days BMI: 31.217481789802285 weight classification: obese
Paitent name: DED567 age: 58 Years 5 Months 5 Days BMI: 32.74416118146279 weight classification: obese
Paitent name: DEF444 age: 24 Years 11 Months 25 Days BMI: 31.462672275229988 weight classification: obese
Paitent name: BDF777 age: 93 Years 10 Months 11 Days BMI: 14.705367459122582 weight classification: underweight
Paitent name: BDF098 age: 86 Years 0 Months 13 Days BMI: 13.863739248528747 weight classification: underweight
Paitent name: DDC345 age: 54 Years 3 Months 19 Days BMI: 16.45600644235146 weight classification: underweight
Paitent name: DDD222 age: 73 Years 9 Months 0 Days BMI: 18.166204254194742 weight classification: underweight
Paitent name: DDD555 age: 66 Years 10 Months 0 Days BMI: 17.632653061224488 weight classification: underweight
Paitent name: DEF666 age: 65 Years 10 Months 22 Days BMI: 17.68978885166924 weight classification: underweight
Paitent name: ABE123 age: 69 Years 6 Months 19 Days BMI: 28.010411951109102 weight classification: overweight
Paitent name: ABD111 age: 72 Years 8 Months 0 Days BMI: 26.122448979591837 weight classification: overweight
Paitent name: ABE165 age: 23 Years 3 Months 9 Days BMI: 26.491508201480624 weight classification: overweight
Paitent name: ABE329 age: 82 Years 0 Months 7 Days BMI: 25.46401086464464 weight classification: overweight
Paitent name: DDD124 age: 44 Years 6 Months 27 Days BMI: 27.15271058955713 weight classification: overweight
Paitent name: DED675 age: 45 Years 6 Months 29 Days BMI: 28.735632183908045 weight classification: overweight
Paitent name: DED879 age: 22 Years 9 Months 1 Days BMI: 28.73469387755102 weight classification: overweight
Paitent name: DEF555 age: 27 Years 1 Months 24 Days BMI: 25.847768218818715 weight classification: overweight
Paitent name: ABC234 age: 19 Years 7 Months 19 Days BMI: 23.057725694444446 weight classification: normal
Paitent name: ABD221 age: 50 Years 11 Months 0 Days BMI: 21.872422819032593 weight classification: normal
Paitent name: ABD176 age: 55 Years 11 Months 3 Days BMI: 21.132713440405748 weight classification: normal
Paitent name: ABD231 age: 55 Years 11 Months 29 Days BMI: 20.9572742022715 weight classification: normal
Paitent name: ABD321 age: 59 Years 11 Months 9 Days BMI: 20.429418362441915 weight classification: normal
Paitent name: ABD444 age: 57 Years 5 Months 6 Days BMI: 20.820939916716245 weight classification: normal
Paitent name: ABD401 age: 63 Years 9 Months 22 Days BMI: 21.513858510523864 weight classification: normal
Paitent name: ABD007 age: 22 Years 2 Months 17 Days BMI: 21.62964876033058 weight classification: normal
Paitent name: ABC008 age: 83 Years 1 Months 19 Days BMI: 19.77769866698311 weight classification: normal
Paitent name: ABC101 age: 86 Years 0 Months 13 Days BMI: 18.556773222226116 weight classification: normal
Paitent name: ABC201 age: 26 Years 10 Months 7 Days BMI: 20.303697560696612 weight classification: normal
我认为问题出在 while 类中的链表类中：
while curr.next is not None:
if curr.next.data.points < data.points:
break
但是，我不确定我需要将其调整为什么，尽管我知道它需要调整
非常感谢！
答案 0 :(得分：1)
您不希望您的链表担心如何比较患者。只需覆盖患者类别的 < 运算符，这样比较两个患者就会自动给出您想要的顺序。
现在你的链表类不关心所有那些花哨的规则，因为它们应该由 Patient 类处理。链表只是检查
while curr.next is not None:
if curr.next.data < data:
break
这样做的方法是在 Patient 类上定义一个名为 __lt__ 的函数。字母“lt”是“小于”的缩写，在代码中使用“<”时会用到。同样，它会自动在排序中被引用。
另见Is it possible to overload the multiple comparison syntax in python?
这是一个快速演示：
import random
class Patient:
def __init__(self, points, bmi):
self.points = points
self.bmi = bmi
def __str__(self):
return '{}, {}'.format(self.points, self.bmi)
def __lt__(self, other):
if self.points < other.points:
return True
if self.bmi < 18.5:
if self.bmi > other.bmi:
return True
else:
if self.bmi < other.bmi:
return True
return False
patients = [
Patient(32, 25),
Patient(32, 24),
Patient(32, 18),
Patient(32, 15),
Patient(20, 25),
Patient(20, 24),
Patient(20, 18),
Patient(20, 15),
]
random.shuffle(patients)
patients.sort()
for patient in patients:
print(patient)
20、18
20、15
20、24
20、25
32、18
32、24
32、15
32、25
答案 1 :(得分：0)
定义 __lt__ 以按顺序比较条件：
def __lt__(self, other):
if self.Points < other.Points:
return True
elif self.Points == other.Points:
if self.bmi < other.bmi:
return True
else:
return False
else: # self.Points > other.Points
return False