python—實例3
In [2]: sys.path Out[2]: ['', '/usr/bin', '/usr/lib64/python2.7/site-packages/MySQL_python-1.2.5-py2.7-linux-x86_64.egg', '/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/lib/python2.7/site-packages', '/usr/lib/python2.7/site-packages/python_memcached-1.58-py2.7.egg', '/usr/lib/python2.7/site-packages/IPython/extensions', '/root/.ipython']
2.自定義模塊目錄
方法一:sys.path.append(),一般加在目錄列表最後
In [3]: sys.path.append("/root/python/") In [4]: sys.path Out[4]: ['', '/usr/bin', '/usr/lib64/python2.7/site-packages/MySQL_python-1.2.5-py2.7-linux-x86_64.egg', '/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/lib/python2.7/site-packages', '/usr/lib/python2.7/site-packages/python_memcached-1.58-py2.7.egg', '/usr/lib/python2.7/site-packages/IPython/extensions', '/root/.ipython', '/root/python/']
方法二:修改環境變量,一般加在目錄列表前面
vim /root/.bashrc # 加入 export PYTHONPATH=/root/python source /root/.bashrc # 刷新
例子:統計一個文件,行數、單詞數、字符數(和wc命令相同效果)
說明:為了避免使用split切割之後,最後多出一個空字符串,而使用count()
#/usr/bin/env python def count(s): char = len(s) words = len(s.split()) lines = s.count("\n") print lines,words,char file1 = open("/etc/passwd","r") s = file1.read() count(s)
3.腳本形式,導入模塊,腳本名字不能是數字,會產生一個編譯文件
例子:
#!/usr/bin/env python import wc
說明:目錄下生產編譯文件:wc.pyc
4.py和wc.py的__name__內置變量不一樣,前者是wc,或者是__main__,修改wc.py,執行自己時,輸出自己的結果,被調用時,執行不顯示源結果:
wc.py:
#/usr/bin/env python def count(s): char = len(s) words = len(s.split()) lines = s.count("\n") print lines,words,char if __name__ == "__main__": file1 = open("/etc/passwd","r") s = file1.read() count(s)
test.py:
#!/usr/bin/env python import wc s = open("/root/python/10.py","r").read() wc.count(s)
5.包的形式,導入模塊
四種導入方法:在包目錄dir下創建一個__init__.py空文件
方法一:
from dir import wc wc.count("abc")
方法二:
import dir.wc dir.wc.count("abc")
方法三:
from dir.wc import count count("abc")
方法四:別名
from dir.wc import count as count count("abc")
6.面向對象編程:python、java、C++;面向過程編程:C、函數式編程、shell
類的(靜態)屬性:(人類的五官,理解為變量)
類的(動態)方法:(人類吃穿住行,理解為一個函數)
對象:類的實例化,之後才能有屬性和方法
7.類的創建
類的方法中,至少有一個參數self
調用屬性時,不帶括號
調用方法時,使用括號;方法調用屬性時,至少有一個self參數
屬性調用其他方法:類名.屬性名
例子:
class People(): color = "yellow" def think(self): self.color = "black" print ("My color is %s "% (self.color)) ren = People() # 類的實例化 print ren.color # 類的屬性外部調用 ren.think() # 類的方法外部調用,如加上print,則多一個默認return值none
運行結果:
yellow
My color is black
8.私有屬性在定義的類中的內部函數中被調用
例子:
class People(): color = "yellow" __age = 27 def think(self): self.color = "black" print self.__age # 內部函數調用類的私有屬性,外部函數不能直接調用 print ("My color is %s "% (self.color)) ren = People() print ren.color ren.think()
9.外部調用私有屬性(格式:實例化名._類名屬性名),一般只是測試用
例子:
class People(): color = "yellow" __age = 27 def think(self): self.color = "black" print self.__age print ("My color is %s "% (self.color)) ren = People() print ren.color ren.think() print ren._People__age # 外部調用私有屬性
10.類的方法
公有方法:內部和外部都可以調用
私有方法:內部函數調用
動態方法:classmethod()函數處理,沒有被調用的類的其他參數不會加載進內存中
靜態方法:
方法的定義和函數一樣,但是需要把self作為第一個參數,如果還是有其他參數,繼續加上;類實例化之後,采用“類名.方法名()”調用
例子1:私有方法調用
class People(): color = "yellow" __age = 27 def __think(self): self.color = "black" print self.__age print ("My color is %s "% (self.color)) def test(self): self.__think() # 類的私有方法調用 ren = People() ren.test() # 類的私有方法調用
例子2:動態方法調用
class People(): color = "yellow" __age = 27 def __think(self): self.color = "black" print self.__age print ("My color is %s "% (self.color)) def test(self): print ("Testing...") cm = classmethod(test) # 動態方法定義 ren = People() ren.cm() # 動態方法調用
例子3:靜態方法調用:
類函數不帶self參數,該函數使用staticmethod()函數處理(如果不處理,缺少self,,調用時會報錯),加載關於這個類的所有東西
class People(): color = "yellow" __age = 27 def __think(self): self.color = "black" print self.__age print ("My color is %s "% (self.color)) def test(): # 內部函數,不帶self print ("Testing...") #print People.color # 因為沒有self,不能調用該類的屬性 cm = staticmethod(test) # 靜態方法定義 ren = People() ren.cm() # 靜態方法調用
例子4:加裝飾器,只對下面的一個函數起作用,就可以使用類的方法調用了
class People(): color = "yellow" __age = 27 def __think(self): self.color = "black" print self.__age print ("My color is %s "% (self.color)) @classmethod # 加裝飾器 def test(self): # 帶self print ("Testing...") @staticmethod # 加裝飾器 def test1(): # 不帶self print ("Testing1..") ren = People() People.test() # 類的方法調用 People.test1() # 類的方法調用
python—實例3