再次使用python未绑定方法
这让我陷入了困境(对不起,我对python还是很陌生) 谢谢你的帮助 错误 MostFrequent()必须与一起调用 学生实例作为第一个参数 (却一无所获) 这个Student.MostFrequent()在末尾(最后一行)一直被调用,该def是类中的最后一个def再次使用python未绑定方法,python,class,Python,Class,这让我陷入了困境(对不起,我对python还是很陌生) 谢谢你的帮助 错误 MostFrequent()必须与一起调用 学生实例作为第一个参数 (却一无所获) 这个Student.MostFrequent()在末尾(最后一行)一直被调用,该def是类中的最后一个def someStudent = Student(someRow) 编辑命名约定 我的长代码 import csv class Student: sports = [] ftopics = [] stopics
someStudent = Student(someRow)
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__
使用Student().MostFrequent()
编辑:
注意使用类属性,这很危险。这里有一个例子:
>>> 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'
>>>
正如您所见,我修改了marco的嗜好,francesco的嗜好也随之修改。在您的类def中,方法定义
def MostFrequent(self,mostFrequent):
有一个额外的变量mostFrequent,您可能不希望它出现。尝试更改为:
def MostFrequent(self):
您很少对类定义调用方法(
Student
)
几乎总是创建类的实例
someStudent = Student(someRow)
然后调用实例(“对象”)上的方法,someStudent
someStudent.MostFrequent()
首先阅读命名约定: 方法名称和实例变量 second您正在调用类
Student
上的mostFrequest
,而不是它的实例。改为在实例上使用该方法:
student = Student(row)
student.MostFrequent()
MostFrequent表示您试图使用静态方法,而不是实例方法。所以您必须首先通过调用Student()创建实例,然后对其调用MostFrequent()
注:如果这不是某个神秘项目的一部分,我建议您遵循PEP 8,使用最常用的方法名。首先,我建议将函数名改为小写 将
MostFrequent
用作静态方法会导致出现错误。为此,需要显式地传递Student
的实例作为第一个参数
如果直接对学生
的实例调用,该实例将作为第一个参数隐式传递
考虑使用
staticmethod
decorator静态使用函数。您可能想要的是将最常见的定义为:
这是否适用于像:def uu init uuu(self,row)这样的构造函数?steve说如何从方法定义中删除最频繁的参数,但是您得到的错误与您不使用实例的事实有关class@TheMYYN:没有。也许我匆忙回答了这个问题,但他犯了那个错误,因为他调用了类上的方法,而不是对象。要在类上调用方法,有classmethod
和staticmethod
修饰符。查看文档了解它们的用法。这正是我在django validator字段中所需要的,我不想在该字段中创建validator类的实例,但validators=[ValidatorClass().function\u name]
正是我需要做的!我想在这种情况下,这会抱怨错误的论点数量,还是没有?总是很高兴看到一个CS毕业生在一个嘶嘶适合
student = Student(row)
student.MostFrequent()
@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