【Python实战14】继承Python内置的list

"定义Atylete类"
class Atylete:
def __init__(self,a_name,a_birthday=None,a_time=[]):
self.name=a_name
self.birthday=a_birthday
self.time=a_time
def top3(self):
return(sorted(set([sanitize(t) for t in self.time]))[0:3])
def add_time(self,time_value):
self.time.append(time_value)
def add_times(self,list_of_time):
self.time.extend(list_of_time)
"""转换时间格式"""
def sanitize(time_string):
if ‘-‘ in time_string:
splitter=‘-‘
elif ‘:‘ in time_string:
splitter=‘:‘
else:
return(time_string)
(mins,secs)=time_string.split(splitter)
return(mins+‘.‘+secs)
"""读取文件内容，并按逗号进行拆分"""
def get_coach_data(filename):
try:
with open(filename) as file:
data = file.readline()
temp=data.strip().split(‘,‘)
return(Atylete(temp.pop(0),temp.pop(0),temp))
except IOError as error:
print(‘File Error:‘+str(error))
return(None)
"""读取文件的内容"""
james = get_coach_data(‘james.txt‘)
julie = get_coach_data(‘julie.txt‘)
mikey = get_coach_data(‘mikey.txt‘)
sarah = get_coach_data(‘sarah.txt‘)
"""打印姓名、生日和最快的三个时间"""
print(james.name+"的生日是："+james.birthday+"，最快的三个时间是："+str(james.top3()))
print(julie.name+"的生日是："+julie.birthday+"，最快的三个时间是："+str(julie.top3()))
print(mikey.name+"的生日是："+mikey.birthday+"，最快的三个时间是："+str(mikey.top3()))
print(sarah.name+"的生日是："+sarah.birthday+"，最快的三个时间是："+str(sarah.top3()))

在进行代码修改之前，我们首先了解下如何继承一个类，这里以继承list类为例：

>>> class NameList(list):
def __init__(self,a_name):
list.__init__([])
self.name=a_name这里定义了一个NameList类，继承自list类，接下来实例化一个NameList类的实例：

>>> john=NameList(‘john‘)
>>> type(john)

>>>
>>> dir(john)
[‘__add__‘, ‘__class__‘, ‘__contains__‘, ‘__delattr__‘, ‘__delitem__‘, ‘__dict__‘, ‘__dir__‘, ‘__doc__‘, ‘__eq__‘, ‘__format__‘, ‘__ge__‘, ‘__getattribute__‘, ‘__getitem__‘, ‘__gt__‘, ‘__hash__‘, ‘__iadd__‘, ‘__imul__‘, ‘__init__‘, ‘__iter__‘, ‘__le__‘, ‘__len__‘, ‘__lt__‘, ‘__module__‘, ‘__mul__‘, ‘__ne__‘, ‘__new__‘, ‘__reduce__‘, ‘__reduce_ex__‘, ‘__repr__‘, ‘__reversed__‘, ‘__rmul__‘, ‘__setattr__‘, ‘__setitem__‘, ‘__sizeof__‘, ‘__str__‘, ‘__subclasshook__‘, ‘__weakref__‘, ‘append‘, ‘clear‘, ‘copy‘, ‘count‘, ‘extend‘, ‘index‘, ‘insert‘, ‘name‘, ‘pop‘, ‘remove‘, ‘reverse‘, ‘sort‘]通过dir函数我们可以看到john对象具有的所有的功能，可以看到这些功能都是继承自list类的

>>> john
[]
>>> john.name
‘john‘
>>> john.append(‘Bass player‘)
>>> john
[‘Bass player‘]
>>> john.extend([‘Composer‘,‘Musician‘])
>>> john
[‘Bass player‘, ‘Composer‘, ‘Musician‘]可以看到john可以随意的使用list的所有功能。

下面就让我们修改之前的代码吧，修改后的代码如下：

"定义Atylete类"
class AtyleteList(list):
def __init__(self,a_name,a_birthday=None,a_time=[]):
list.__init__([])
self.name=a_name
self.birthday=a_birthday
self.extend(a_time)
def top3(self):
return(sorted(set([sanitize(t) for t in self]))[0:3])
def add_time(self,time_value):
self.time.append(time_value)
def add_times(self,list_of_time):
self.time.extend(list_of_time)
"""转换时间格式"""
def sanitize(time_string):
if ‘-‘ in time_string:
splitter=‘-‘
elif ‘:‘ in time_string:
splitter=‘:‘
else:
return(time_string)
(mins,secs)=time_string.split(splitter)
return(mins+‘.‘+secs)
"""读取文件内容，并按逗号进行拆分"""
def get_coach_data(filename):
try:
with open(filename) as file:
data = file.readline()
temp=data.strip().split(‘,‘)
return(AtyleteList(temp.pop(0),temp.pop(0),temp))
except IOError as error:
print(‘File Error:‘+str(error))
return(None)
"""读取文件的内容"""
james = get_coach_data(‘james.txt‘)
julie = get_coach_data(‘julie.txt‘)
mikey = get_coach_data(‘mikey.txt‘)
sarah = get_coach_data(‘sarah.txt‘)
"""打印姓名、生日和最快的三个时间"""
print(james.name+"的生日是："+james.birthday+"，最快的三个时间是："+str(james.top3()))
print(julie.name+"的生日是："+julie.birthday+"，最快的三个时间是："+str(julie.top3()))
print(mikey.name+"的生日是："+mikey.birthday+"，最快的三个时间是："+str(mikey.top3()))
print(sarah.name+"的生日是："+sarah.birthday+"，最快的三个时间是："+str(sarah.top3()))
运行结果如下：

>>> ================================ RESTART ================================
>>>
James Lee的生日是：2002-3-14，最快的三个时间是：[‘2.01‘, ‘2.16‘, ‘2.22‘]
Julie Jones的生日是：2002-8-17，最快的三个时间是：[‘2.11‘, ‘2.23‘, ‘2.59‘]
Mikey McManus的生日是：2002-2-24，最快的三个时间是：[‘2.22‘, ‘2.31‘, ‘2.38‘]
Sarah Sweeney的生日是：2002-6-17，最快的三个时间是：[‘2.18‘, ‘2.21‘, ‘2.22‘]

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