python基础5

2021-11-13 03:12:20

模块

什么是模块：所有以.py结尾的都可以认为是一个模块

例：编写一个.py结尾的文件实现四则运算，再用另一个.py文件去导入

###cacl.py文件，实现四则运算###

#!/usr/bin/env python

#coding:utf-8

from __future__ import division###__future__该模块中含有python3.x的方法，导入就可以使用这些方法###

def add(x,y):

return x + y

def sub(x,y):

return x -y

def multi(x,y):

return x*y

def divi(x,y):

return x/y

###hello.py文件，导入cacl.py文件###

#!/usr/bin/env python

#coding:utf-8

import cacl

print cacl.add(2,5)

print cacl.divi(5,2)

执行结果：

2.5

####导入模块的三种方法###

1 import cacl###导入cacl模块，使用时一定要加上cacl

例：

import cacl

print cacl.add(2,5)

print cacl.divi(5,2)

2 from cacl import add###导入cacl模块中的add方法，使用时不用加cacl，可以直接使用###

例：

from cacl import add

print add(2,5)

3 from cacl import add as myadd###如果当前py代码包含add方法，但仍然想要使用cacl中的add方法，只需将cacl中的add方法重命名即可###

例：

from cacl import add as myadd

def add(x,y):

return x+y+1

print add(2,5)

print myadd(2,5)

执行结果：

###导入模块的灵活应用####

1 导入模块的多个方法

from cacl import sub,multi###导入加法，减法###

from cacl import add as myadd

def add(x,y):

return x+y+1

print add(2,5)

print sub(2,5)

print multi(2,5)

print myadd(2,5)

####路径搜索，搜索路径###

添加一路径，让路径搜索时导入相应的自定义模块

路径搜索：重点是在搜索

搜索路径：重点是在路径，即sys.path显示出来的路径

搜索路径：当你写了一个.py文件，想要在任何时刻的的都可以导入该模块，则需将该.py文件加入搜索路径中

In [3]: sys.path

Out[3]:

['',

'/usr/bin',

'/usr/lib64/python27.zip',

'/usr/lib64/python2.7',

'/usr/lib64/python2.7/plat-linux2',

'/usr/lib64/python2.7/lib-tk',

'/usr/lib64/python2.7/lib-old',

'/usr/lib64/python2.7/lib-dynload',

'/usr/lib64/python2.7/site-packages',

'/usr/lib64/python2.7/site-packages/gtk-2.0',

'/usr/lib/python2.7/site-packages',

'/usr/lib/python2.7/site-packages/IPython/extensions',

'/home/kiosk/.ipython']

In [4]: sys.path.append('/home/kiosk/PycharmProjects/pythonbasic/day05/')

In [5]: sys.path

Out[5]:

['',

'/usr/bin',

'/usr/lib64/python27.zip',

'/usr/lib64/python2.7',

'/usr/lib64/python2.7/plat-linux2',

'/usr/lib64/python2.7/lib-tk',

'/usr/lib64/python2.7/lib-old',

'/usr/lib64/python2.7/lib-dynload',

'/usr/lib64/python2.7/site-packages',

'/usr/lib64/python2.7/site-packages/gtk-2.0',

'/usr/lib/python2.7/site-packages',

'/usr/lib/python2.7/site-packages/IPython/extensions',

'/home/kiosk/.ipython',

'/home/kiosk/PycharmProjects/pythonbasic/day05/']

In [6]: import decorate###加入搜索路径后，则可以导入###

hello....

1.00119495392

hello1....

None

hello2....

2.00213503838

hello3....

In [7]: sys.path.pop()

Out[7]: '/home/kiosk/PycharmProjects/pythonbasic/day05/'###一旦弹出，搜索路径中没有该路径时，就无法导入###

In [9]: sys.path

Out[9]:

['',

'/usr/bin',

'/usr/lib64/python27.zip',

'/usr/lib64/python2.7',

'/usr/lib64/python2.7/plat-linux2',

'/usr/lib64/python2.7/lib-tk',

'/usr/lib64/python2.7/lib-old',

'/usr/lib64/python2.7/lib-dynload',

'/usr/lib64/python2.7/site-packages',

'/usr/lib64/python2.7/site-packages/gtk-2.0',

'/usr/lib/python2.7/site-packages',

'/usr/lib/python2.7/site-packages/IPython/extensions',

'/home/kiosk/.ipython']

In [10]: import decorate

---------------------------------------------------------------------------

ImportError Traceback (most recent call last)

<ipython-input-10-96bbe2666044> in <module>()

----> 1 import decorate

ImportError: No module named decorate

###在day05下有一个hello.py文件，day06下也有一个hello.py文件，则是读取第一次导入的内容####

In [11]: sys.path.append('/home/kiosk/PycharmProjects/pythonbasic/day05/')

In [14]: import hello

In [15]: hello.hello1()

hello1.....inday05###day05下hello.py文件的内容###

In [16]: sys.path.append('/home/kiosk/PycharmProjects/pythonbasic/day06/')###将day06也加入搜索路径###

In [17]: import hello

In [18]: hello.hello1()

hello1.....inday05###显示的仍是day05的内容####

In [19]: sys.path

Out[19]:

['',

'/usr/bin',

'/usr/lib64/python27.zip',

'/usr/lib64/python2.7',

'/usr/lib64/python2.7/plat-linux2',

'/usr/lib64/python2.7/lib-tk',

'/usr/lib64/python2.7/lib-old',

'/usr/lib64/python2.7/lib-dynload',

'/usr/lib64/python2.7/site-packages',

'/usr/lib64/python2.7/site-packages/gtk-2.0',

'/usr/lib/python2.7/site-packages',

'/usr/lib/python2.7/site-packages/IPython/extensions',

'/home/kiosk/.ipython',

'/home/kiosk/PycharmProjects/pythonbasic/day05/',

'/home/kiosk/PycharmProjects/pythonbasic/day06/']

In [20]: sys.path.pop()

Out[20]: '/home/kiosk/PycharmProjects/pythonbasic/day06/'

In [21]: sys.path.insert(0,'/home/kiosk/PycharmProjects/pythonbasic/day06/')###就算将day06加到最前面，读取的仍然是day05的内容###

In [22]: import hello

In [23]: hello.hello1()

hello1.....inday05

####在还没有导入模块时，导入相同名字的模块，则，哪个路径在前，就先读取哪个，之后就算更改路径，仍然读取最初的模块####

In [2]: sys.path

Out[2]:

['',

'/usr/bin',

'/usr/lib64/python27.zip',

'/usr/lib64/python2.7',

'/usr/lib64/python2.7/plat-linux2',

'/usr/lib64/python2.7/lib-tk',

'/usr/lib64/python2.7/lib-old',

'/usr/lib64/python2.7/lib-dynload',

'/usr/lib64/python2.7/site-packages',

'/usr/lib64/python2.7/site-packages/gtk-2.0',

'/usr/lib/python2.7/site-packages',

'/usr/lib/python2.7/site-packages/IPython/extensions',

'/home/kiosk/.ipython']

In [3]: sys.path.insert(0,'/home/kiosk/PycharmProjects/pythonbasic/day06/')

In [4]: sys.path.append('/home/kiosk/PycharmProjects/pythonbasic/day06/')

In [5]: sys.path

Out[5]:

['/home/kiosk/PycharmProjects/pythonbasic/day06/',

'',

'/usr/bin',

'/usr/lib64/python27.zip',

'/usr/lib64/python2.7',

'/usr/lib64/python2.7/plat-linux2',

'/usr/lib64/python2.7/lib-tk',

'/usr/lib64/python2.7/lib-old',

'/usr/lib64/python2.7/lib-dynload',

'/usr/lib64/python2.7/site-packages',

'/usr/lib64/python2.7/site-packages/gtk-2.0',

'/usr/lib/python2.7/site-packages',

'/usr/lib/python2.7/site-packages/IPython/extensions',

'/home/kiosk/.ipython',

'/home/kiosk/PycharmProjects/pythonbasic/day05/']

In [6]: import hello

In [7]: hello.hello1()###读取day06的模块的内容###

hello1......in day06

In [8]: sys.path.pop()###弹出day05###

Out[8]: '/home/kiosk/PycharmProjects/pythonbasic/day05/'

In [9]: sys.path.insert(0,'/home/kiosk/PycharmProjects/pythonbasic/day05/')###将day05的路径加到最前面###

In [10]: sys.path

Out[10]:

['/home/kiosk/PycharmProjects/pythonbasic/day05/',

'/home/kiosk/PycharmProjects/pythonbasic/day06/',

'',

'/usr/bin',

'/usr/lib64/python27.zip',

'/usr/lib64/python2.7',

'/usr/lib64/python2.7/plat-linux2',

'/usr/lib64/python2.7/lib-tk',

'/usr/lib64/python2.7/lib-old',

'/usr/lib64/python2.7/lib-dynload',

'/usr/lib64/python2.7/site-packages',

'/usr/lib64/python2.7/site-packages/gtk-2.0',

'/usr/lib/python2.7/site-packages',

'/usr/lib/python2.7/site-packages/IPython/extensions',

'/home/kiosk/.ipython']

In [11]: import hello###导入hello模块###

In [12]: hello.hello1()###读取的仍然是day06下的内容###

hello1......in day06

####创建包###

import test.cacl as cacl

def add(x,y):

return x+y+1

print add(2,5)

print cacl.sub(2,5)

####若是只导入test包，则需要在__init__.py文件里导入模块###

保存包的一些信息，其实是在解释执行test包里面的__init__.py文件

###类class###

编程：

面向过程

面向对象

面向函数

class Animals(object)###定义一个类，关键字class，类的名称的第一个字母一定要大写###

#!/usr/bin/env python

#coding:utf-8

class Animals(object):###定义类###

cn = 'china' ###类变量###

def __init__(self,name,age):###构造函数，后面跟你要传递的参数

self.name = name###self就是实例化的变量名，此时，self指的是haha，self.name是实例化属性，静态属性

self.age = age

def eating(self):###方法，与函数唯一的区别时self，动态属性###

print "%s is eating..."%self.name

def drink(self):

print "%s is drinking..."%self.name

haha = Animals("fentiao",5)###实例化###

haha.eating()

haha.drink()

执行结果:

/usr/bin/python2.7 /home/kiosk/PycharmProjects/pythonbasic/day06/test/myclass.py

fentiao is eating...

fentiao is drinking...

Process finished with exit code 0

定义一个类变量和在构造函数__init__()内写入参数的区别，每次实例化的时候，都会执行构造函数，因此，若是执行次数很多的时候，构造函数里的参数就也执行很多次，因此，定义一个类变量会更方便

若是想要传递的参数不想要改变，可以加双下划线

###可以改变###

class Animals(object):

cn = 'china' ###类变量###

def __init__(self,name,age,gender):

self.name = name

self.age = age

self.gender = gender

def eating(self):

print "%s is eating..."%self.name

def drink(self):

print "%s is drinking..."%self.name

fentiao = Animals("fentiao",5,'male')

fentiao.eating()

fentiao.drink()

print fentiao.gender,fentiao.name

fentiao.gender = "female"

print fentiao.gender

###不可以改变###

class Animals(object):

cn = 'china' ###类变量###

def __init__(self,name,age,gender):

self.name = name

self.age = age

self.__gender = gender###以双下划线开头的变量是私有变量，在类外不可以访问，因为python编译器会将双下划线开头的变量进行更改，因此要打印双下划线开头的变量会报错（因为已经发生了改变，找不到）###

def eating(self):

print "%s is eating..."%self.name

def drink(self):

print "%s is drinking..."%self.name

fentiao = Animals("fentiao",5,'male')

fentiao.eating()

fentiao.drink()

print fentiao.__gender###打印不出，会报错###

想要打印，在类里再添加一个打印私有变量的方法：

class Animals(object):

cn = 'china' ###类变量###

def __init__(self,name,age,gender):

self.name = name

self.age = age

self.__gender = gender

def eating(self):

print "%s is eating..."%self.name

def drink(self):

print "%s is drinking..."%self.name

def got_gender(self):

return self.__gender

fentiao = Animals("fentiao",5,'male')

fentiao.eating()

fentiao.drink()

fentiao.__gender = "female"

print fentiao.__gender

print fentiao.got_gender()

执行结果：

/usr/bin/python2.7 /home/kiosk/PycharmProjects/pythonbasic/day06/test/myclass.py

fentiao is eating...

fentiao is drinking...

female

male###会发现没有改变###

Process finished with exit code 0

###私有方法###

class Animals(object):

cn = 'china' ###类变量###

def __init__(self,name,age,gender):

self.name = name

self.age = age

self.__gender = gender

def eating(self):

print "%s is eating..."%self.name

def drink(self):

print "%s is drinking..."%self.name

def got_gender(self):

self.__hello()

return self.__gender

def __hello(self):###定义私有方法###

print "hello..."

fentiao = Animals("fentiao",5,'male')

print fentiao.got_gender()

print fentiao.__hello()###无法调用，会报错###

执行结果：

/usr/bin/python2.7 /home/kiosk/PycharmProjects/pythonbasic/day06/test/myclass.py

hello...

male

Traceback (most recent call last):

File "/home/kiosk/PycharmProjects/pythonbasic/day06/test/myclass.py", line 84, in <module>

print fentiao.__hello()

AttributeError: 'Animals' object has no attribute '__hello'

Process finished with exit code 0

###若是有不想被人访问的方法，则可以把它定义成私有方法###

面向对象的特性：

1 封装性：私有方法和私有属性

2 继承：继承父类的方法和属性

3 多态

###多态###

class Animals(object):###定义类###

def __init__(self,name,age):###构造函数，后面跟你要传递的参数

self.name = name###self就是实例化的变量名，此时，self指的是haha，self.name是实例化属性，静态属性

self.age = age

def eating(self):###方法，与函数唯一的区别时self，动态属性###

print "%s is eating..."%self.name

def drink(self):

print "%s is drinking..."%self.name

haha = Animals("fentiao",5)###实例化###

haha.eating()

haha.drink()

class Cat(Animals):

def eating(self):

print '%s eating fish...'%(self.name)

class Dog(Animals):

def eating(self):

print "%s eating gutou......"%(self.name)

a1 = Animals('animals1',2)

a1.eating()

c1 = Cat('cat1',5)

c1.eating()

d1 = Dog('dog1',4)

d1.eating()

执行结果：

/usr/bin/python2.7 /home/kiosk/PycharmProjects/pythonbasic/day06/test/myclass.py

fentiao is eating...

fentiao is drinking...

animals1 is eating...

cat1 eating fish...

dog1 eating gutou......

###析构函数###

class Animals(object):###定义类###

def __init__(self,name,age):###构造函数，后面跟你要传递的参数

self.name = name###self就是实例化的变量名，此时，self指的是haha，self.name是实例化属性，静态属性

self.age = age

def eating(self):###方法，与函数唯一的区别时self，动态属性###

print "%s is eating..."%self.name

def drink(self):

print "%s is drinking..."%self.name

def __del__(self):

print "that's all,game over"

haha = Animals("fentiao",5)###实例化###

haha.eating()

haha.drink()

class Cat(Animals):

def eating(self):

print '%s eating fish...'%(self.name)

class Dog(Animals):

def eating(self):

print "%s eating gutou......"%(self.name)

a1 = Animals('animals1',2)

a1.eating()

c1 = Cat('cat1',5)

c1.eating()

d1 = Dog('dog1',4)

d1.eating()

执行结果：

/usr/bin/python2.7 /home/kiosk/PycharmProjects/pythonbasic/day06/test/myclass.py

fentiao is eating...

fentiao is drinking...

animals1 is eating...

cat1 eating fish...

dog1 eating gutou......

that's all,game over

Process finished with exit code 0

###或者####

class Animals(object):###定义类###

def __init__(self,name,age):###构造函数，后面跟你要传递的参数

self.name = name###self就是实例化的变量名，此时，self指的是haha，self.name是实例化属性，静态属性

self.age = age

def eating(self):###方法，与函数唯一的区别时self，动态属性###

print "%s is eating..."%self.name

def drink(self):

print "%s is drinking..."%self.name

def __del__(self):

print "that's all,game over"

haha = Animals("fentiao",5)###实例化###

haha.eating()

haha.drink()

class Cat(Animals):

def eating(self):

print '%s eating fish...'%(self.name)

class Dog(Animals):

def eating(self):

print "%s eating gutou......"%(self.name)

a1 = Animals('animals1',2)

a1.eating()

del(a1)

c1 = Cat('cat1',5)

c1.eating()

del(c1)

d1 = Dog('dog1',4)

d1.eating()

del(d1)

执行结果：

/usr/bin/python2.7 /home/kiosk/PycharmProjects/pythonbasic/day06/test/myclass.py

fentiao is eating...

fentiao is drinking...

animals1 is eating...

that's all,game over

cat1 eating fish...

that's all,game over

dog1 eating gutou......

that's all,game over

Process finished with exit code 0

######Animals.__init__(self,name,age)####

class Animals(object):###定义类###

def __init__(self,name,age):###构造函数，后面跟你要传递的参数

self.name = name###self就是实例化的变量名，此时，self指的是haha，self.name是实例化属性，静态属性

self.age = age

def eating(self):###方法，与函数唯一的区别时self，动态属性###

print "%s is eating..."%self.name

def drink(self):

print "%s is drinking..."%self.name

def __del__(self):

print "that's all,game over"

haha = Animals("fentiao",5)###实例化###

haha.eating()

haha.drink()

class Cat(Animals):

def __init__(self,name,age,color):

Animals.__init__(self,name,age)

self.color = color

def eating(self):

print '%s eating fish...'%(self.name)

def info(self):

print '''

cat info

name:%s

age:%d

color:%s

'''%(self.name,self.age,self.color)

c1 = Cat('cat1',5,'black')

c1.info()

执行结果：

/usr/bin/python2.7 /home/kiosk/PycharmProjects/pythonbasic/day06/test/myclass.py

fentiao is eating...

fentiao is drinking...

cat info

name:cat1

age:5

color:black

that's all,game over

Process finished with exit code 0

#####super(Cat,self).__init__(name,age)####

class Animals(object):###定义类###

def __init__(self,name,age):###构造函数，后面跟你要传递的参数

self.name = name###self就是实例化的变量名，此时，self指的是haha，self.name是实例化属性，静态属性

self.age = age

def eating(self):###方法，与函数唯一的区别时self，动态属性###

print "%s is eating..."%self.name

def drink(self):

print "%s is drinking..."%self.name

def __del__(self):

print "that's all,game over"

haha = Animals("fentiao",5)###实例化###

haha.eating()

haha.drink()

class Cat(Animals):

def __init__(self,name,age,color):

# Animals.__init__(self,name,age)

super(Cat,self).__init__(name,age)

self.color = color

def eating(self):

print '%s eating fish...'%(self.name)

def info(self):

print '''

cat info

name:%s

age:%d

color:%s

'''%(self.name,self.age,self.color)

c1 = Cat('cat1',5,'black')

c1.info()

执行结果：

/usr/bin/python2.7 /home/kiosk/PycharmProjects/pythonbasic/day06/test/myclass.py

fentiao is eating...

fentiao is drinking...

cat info

name:cat1

age:5

color:black

that's all,game over

Process finished with exit code 0

####两个类之间建立联系，继承多个类####

class Realtion(object):

def make_firends(self,obj):

print "%s is %s friends"%(self.name,obj.name)

class Animals(object):###定义类###

def __init__(self,name,age):###构造函数，后面跟你要传递的参数

self.name = name###self就是实例化的变量名，此时，self指的是haha，self.name是实例化属性，静态属性

self.age = age

def eating(self):###方法，与函数唯一的区别时self，动态属性###

print "%s is eating..."%self.name

def drink(self):

print "%s is drinking..."%self.name

def __del__(self):

print "that's all,game over"

haha = Animals("fentiao",5)###实例化###

haha.eating()

haha.drink()

class Cat(Animals,Realtion):

def __init__(self,name,age,color):

# Animals.__init__(self,name,age)

super(Cat,self).__init__(name,age)

self.color = color

def eating(self):

print '%s eating fish...'%(self.name)

def info(self):

print '''

cat info

name:%s

age:%d

color:%s

'''%(self.name,self.age,self.color)

class Dog(Animals,Realtion):

def eating(self):

print "%s eating gutou......"%(self.name)

c1 = Cat('cat1',5,'black')

d1 = Dog("dog1",5)

c1.make_firends(d1)

执行结果:

/usr/bin/python2.7 /home/kiosk/PycharmProjects/pythonbasic/day06/test/myclass.py

fentiao is eating...

fentiao is drinking...

cat1 is dog1 friends

that's all,game over

Process finished with exit code 0

####继承策略###

广度优先策略（效率高）python3

深度优先策略：一直找父类的方法，如果没有找到相应的方法，再去找和c在同一层的类

本文转自blueclo51CTO博客，原文链接： http://blog.51cto.com/12774272/1947897，如需转载请自行联系原作者

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