再次python未绑定方法

Question

这让我陷入了困境（对不起，我对 python 还是很陌生） 感谢您的任何帮助。

错误

print Student.MostFrequent() TypeError: unbound method

MostFrequent() 必须使用 学生实例作为第一个参数 （一无所获）

这个Student.MostFrequent()在最后（最后一行）被调用，def是类中的最后一个def

已编辑 - 命名约定

我的长代码

import csv
class Student:
    sports = []
    ftopics = []
    stopics = []
    choice_list = []
    choice_dict = {}
    def __init__(self, row):
       self.lname, self.fname, self.ID, self.gender, self.sport, self.movie, self.movieyr, self.country, self.ftopic, self.stopic = row
       self.sports.append(self.sport)
       self.ftopics.append(self.ftopic)
       self.stopics.append(self.stopic)
    def print_information(self):
       return (self.lname, self.fname, self.ID, self.gender)
    def print_first(self):
       return (self.lname, self.fname, self.sport)
    def print_second(self):
        return (self.lname, self.fname, self.movie, self.movieyr)
    def print_third(self):
        return (self.lname, self.fname, self.country)
    def print_fourth(self):
        return (self.lname, self.fname, self.ftopic, self.stopic)
    def most_frequent(self):
        for choice in self.choice_list:
                self.choice_dict[choice] = self.choice_dict.get(choice, 0) + 1
        self.mostFrequent = sorted([(v, k) for k, v in self.choice_dict.items()], reverse=True)
        print self.mostFrequent

reader = csv.reader(open('new_mondy_csc_data_revise.csv'), delimiter=',', quotechar='"')
header = tuple(reader.next())
print "%-17s|%-10s|%-6s|%s" %header[:4]
print "-" * 45
students = list(map(Student, reader)) # read all remaining lines
for student in students:
    print "%-17s|%-10s|%-6s|%3s" % student.print_information()

print "%-17s|%-10s|%s" %(header[0],header[1],header[4])
print "-" * 45
for student in students:
    print "%-17s|%-10s|%s" %student.print_first()

print "%-17s|%-10s|%-16s|%s" %(header[0],header[1],header[5],header[6])
print "-" * 45
for student in students:
    print "%-17s|%-10s|%-16s|%s" % student.print_second()

print "%-17s|%-10s|%s" %(header[0],header[1],header[7])
print "-" * 45
for student in students:
    print "%-17s|%-10s|%s" %student.print_third()

print "%-17s|%-10s|%-15s|%s" %(header[0],header[1],header[8],header[9])
print "-" * 45
for student in students:
    print "%-17s|%-10s|%-16s|%s" % student.print_fourth()

k = len(students)    
# Printing all sports that are specified by students
for s in set(Student.sports): # class attribute
    print s, Student.sports.count(s), round(((float(Student.sports.count(s)) / k) *100),1)

# Printing sports that are not picked 
allsports = ['Basketball','Football','Other','Baseball','Handball','Soccer','Volleyball','I do not like sport']
allsports.sort()
for s in set(allsports) - set(Student.sports):
    print s, 0, '0%'
Student.choice_list = Student.sports
X = Student()
X.most_frequent()

#class Search(Student):
#    def __init__(self):
#        Student.__init__

Answer 1

首先阅读PEP-8关于命名约定：

方法名称和实例变量

  Use the function naming rules: lowercase with words separated by
  underscores as necessary to improve readability.

second您在 Student 类上调用 mostFrequest，而不是它的实例。改为在实例上使用该方法：

student = Student(row)
student.MostFrequent()

Answer 2

使用Student().MostFrequent()

编辑：

注意你使用类属性，这是危险的。这里是一个例子：

>>> class Person:
...  name = None
...  hobbies = []
...  def __init__(self, name):
...   self.name = name
... 
>>> a = Person('marco')
>>> b = Person('francesco')
>>> a.hobbies.append('football')
>>> b.hobbies
['football']
>>> a.name
'marco'
>>> b.name
'francesco'
>>> a.name = 'mario'
>>> b.name
'francesco'
>>> a.name
'mario'
>>> 

如你所见，我修改了 marco 的爱好，而 francesco 的爱好也随之改变。

Answer 3

您可能想要的是将most_frequent 定义为classmethod：

@classmethod
def most_frequent(cls):
    for choice in cls.choice_list:
        cls.choice_dict[choice] = cls.choice_dict.get(choice, 0) + 1
    cls.mostFrequent = sorted([(v, k) for k, v in cls.choice_dict.items()], reverse=True)
    return cls.mostFrequent

Answer 4

首先，我建议只将函数名称设为小写。

使用MostFrequent 作为静态方法导致的错误。为此，您需要显式传递Student 的实例作为第一个参数。

如果直接在Student 的实例上调用，该实例将作为第一个参数隐式传递。

考虑使用 staticmethod 装饰器来静态使用函数。

Answer 5

您很少在类定义上调用方法 (Student)

几乎总是你创建一个类的实例

someStudent = Student(someRow)

然后调用实例（“对象”）上的方法someStudent。

someStudent.MostFrequent()

Answer 6

Student.MostFrequent 表示您正在尝试使用静态方法，而不是实例方法。所以你必须先调用 Student() 创建实例，然后调用 MostFrequent() 。

P.S.：如果这不是某个神秘项目的一部分，我敦促您遵循 PEP 8 并使用 most_frequent 作为方法名称。

Answer 7

在你的类定义中，方法定义

def MostFrequent(self,mostFrequent):

具有您可能不希望出现的额外变量 mostFrequent。尝试更改为：

def MostFrequent(self):