python基礎入門之python的類
阿新 • • 發佈：2018-12-22
類
類的例項方法
例項方法的第一個引數必須是”self”。例項方法只能通過類例項進行呼叫，這時候”self”就代表這個類例項本身。通過”self”可以直接訪問例項的屬性，有了init方法，在建立例項的時候，就不能傳入空的引數了，必須傳入與init方法匹配的引數，但self不需要傳。 ?
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class A(object):
# 類的初始化
def __init__(self, name):
self.name = name
print("init class A")
def hello(self):
print("hello {0}".format(self.name))
a = A("shan")
a.hello()
# 輸出
init class A
hello shan
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繼承
繼承
在Python中，同時支援單繼承與多繼承，實現繼承之後，子類將繼承父類的屬性。
一般語法如下：
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class SubClassName(ParentClass1 [, ParentClass2, ...]):
class_suite
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class Animal(object):
def __init__(self, name):
print("你現在正在初始化一個Animal")
def run(self):
print("Animal can run.")
class Bird(Animal): #繼承Animal
def __init__(self):
print("bird")
def fly(self):
print("Bird can fly.")
class Cat(Animal): #繼承Animal
def __init__(self, name, sex):
self.name = nameself.sex = sex
super(Cat, self).__init__(self.name)
print("我是一隻貓，啦啦啦啦")
def jiao(self):
print("miao miao miao miao")
def run(self):
print("我是一隻貓，會上樹來會跑路.")
class BianYi(Cat, Bird): #繼承Cat,Bird
pass
cat = Cat("mao", "man")
# 輸出
你現在正在初始化一個Animal
我是一隻貓，啦啦啦啦
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類中的呼叫方法
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class DbArgs(object):
# 只有類本身才可以呼叫
__host = str("1.1.1.1")
__port = str()
__username = str()
__password = str()
__dbname = str()
# 任何人可以呼叫
name = "ajing"
# 只能例項自己呼叫
_host = "asdlfjasdl"
def getHost(self):
return self.__host
def setHost(self, host):
self.__host = host
dbArgs = DbArgs()
print(dbArgs.getHost())
dbArgs.name = "就是要改你，怎麼的"
print(dbArgs.name)
print(dbArgs._host)
# 輸出
1.1.1.1
就是要改你，怎麼的
asdlfjasdl
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類的應用例子
本例項主要是結合類的初始化，例項化，也使用了之前學的開啟檔案和寫檔案。 ?| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 |
import codecs
class Student(object):
def __init__(self, id, name, score): #初始化 id，name，score
self.id = id
self.name = name
self.score = score
class InitStduents():
def __init__(self): # 初始化中定義一個list，執行init方法，init方法中新增list資料
self.students = list()
self.init()
def init(self):
self.students.append(Student(1001, "aaa", 59))
self.students.append(Student(1002, "bbb", 96))
self.students.append(Student(1003, "ccc", 87))
self.students.append(Student(1004, "ddd", 89))
self.students.append(Student(1005, "eee", 33))
self.students.append(Student(1006, "fff", 85))
self.students.append(Student(1007, "ggg", 78))
self.students.append(Student(1008, "hhh", 97))
self.students.append(Student(1009, "iii", 31))
self.students.append(Student(1010, "jjj", 93))
def sort(self): # 類中的sort方法(list的排序)
return sorted(self.students, key=lambda student: student.score)
def writeFile(self, newStudents): # 類中writeFile方法(把內容寫進檔案)
with codecs.open("sortStudent.txt", "w")as f:
for i in newStudents:
f.write("id = {0}".format(i.id))
f.write("\t")
f.write("name = {0}".format(i.name))
f.write("\t")
f.write("score = {0}".format(i.score))
f.write("\n")
def main():
students = InitStduents()
newStudents = students.sort() http://cz.qwangxiao.com/
students.writeFile(newStudents)
if __name__ == "__main__":
main()
# 檢視newStudents
id = 1009 name = iii score = 31
id = 1005 name = eee score = 33
id = 1001 name = aaa score = 59
id = 1007 name = ggg score = 78
id = 1006 name = fff score = 85
id = 1003 name = ccc score = 87
id = 1004 name = ddd score = 89
id = 1010 name = jjj score = 93
id = 1002 name = bbb score = 96
id = 1008 name = hhh score = 97
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class JinCinCount(object):
def __init__(self, n):
self.n = n
def jc(self, n):
result = 1
if n == 0:
return result
else:
for i in range(1, n+1):
result *= i
return result
def count(self):
count = 0
for i in range(0, int(self.n) + 1):
count += self.jc(i)
print("count = {0}".format(count))
def main():
n = input("Please inpurt a number: ")
jinCinCount = JinCinCount(int(n))
jinCinCount.count()
if __name__ == "__main__":
main()
# 輸出
Please inpurt a number: 5
count = 154
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