• python自动化开发2


    1.python的数据类型之列表

      列表是Python开发语言中最常见的数据类型之一,通过列表可以实现对数据的增删改等常用操作。

      列表的定义:例子

        names = ["Lucy","Lily","jack"]

      列表的常用功能

        1)取出列表中的元素:例子

          

          取出列表的第二个元素:通过下标的方式,下标从0开始计数。

            

          取出列表的最后一个元素:

            

        2)切片:例子 注意列表在切片的时候是包头不包尾。     

          例一:
          names = ["Lucy","Lily","jack","rain"]
          print (names[0:3])
          运行结果如下:
          ['Lucy', 'Lily', 'jack']
          例二:     
          datas = ["jack","john","rain","lily"]
          print(datas[-1])
          运行结果:lily
        3)追加:例子      
          datas = ["jack","john","rain","lily"]
          datas.append("新人")
          print(datas)
          运行结果:['jack', 'john', 'rain', 'lily', '新人']
        4)插入:例子      
          datas = ["jack","john","rain","lily"]
          datas.insert(1,"插入到下标为1的位置上")
          print(datas)
          运行结果:['jack', '插入到下标为1的位置上', 'john', 'rain', 'lily']
        5)修改;例子      
          datas = ["jack","john","rain","lily"]
          datas[2]="lilei"
          print(datas)
          运行结果:['jack', 'john', 'lilei', 'lily']
        6)删除:例子     
          datas = ["jack","john","rain","lily"]
          del datas[2]
          print(datas)
          运行结果:['jack', 'john', 'lily']
          
          
          datas = ["jack","john","rain","lily"]
          datas.remove("jack")
          print(datas)
          运行结果:['john', 'rain', 'lily']
        7)拷贝:例子      
          datas = ["jack","john","rain","lily"]
          data = datas.copy()
          print(data)
          运行结果:['jack', 'john', 'rain', 'lily']
        8)统计:例子      
          datas = ["jack","john","rain","lily","john"]

          print(datas.count("john"))
          运行结果:2
        9)排序和反转:例子
        排序:
          
          datas = ["jack","john","rain","lily","john","1","2"]

          datas.sort()
          print(datas)
          运行结果:['1', '2', 'jack', 'john', 'john', 'lily', 'rain']
        反转:
          
          datas = ["jack","john","rain","lily","john","1","2"]

          datas.reverse()
          print(datas)
          运行结果:['2', '1', 'john', 'lily', 'rain', 'john', 'jack']
        10)获取列表里某个元素的下标位置:例子
          
          datas = ["jack","john","rain","lily","john","1","2"]

          print(datas.index("lily"))
          运行结果:3


    2.python的数据类型之元组
      元组与列表类似,也是存一组数,但是元组一旦创建,便不能再修改,所以又叫只读列表。
      元组只有两个方法,一个是count,另一个是index。
      例子1:    
        datas = ("jack","john","rain","lily","john","1","2")

        print(datas.index("rain"))
        运行结果:2
      例子2:    
        datas = ("jack","john","rain","lily","john","1","2")

        print(datas.count("john"))
        运行结果:2

    3.python的数据类型之字符串
      字符串的特性就是不可修改。
      字符串的一些功能如下:
        1)首字母大写      
          datas = "far across the distance and spaces between us"

          print(datas.capitalize())
          运行结果:Far across the distance and spaces between us

         2)大写全部变小写      
          datas = "Far Across The Tistance And Spaces Between Us"

          print(datas.casefold())
          运行结果:far across the tistance and spaces between us

         3)输出方式      
          datas = "Far Across The Tistance And Spaces Between Us"

          print(datas.center(50,"-"))
          运行结果:--Far Across The Tistance And Spaces Between Us---

         4)统计      
          datas = "Far Across The Tistance And Spaces Between Us Us"

          print(datas.count("Us"))
          运行结果:2

         5)判断字符串是否以...结尾      
          datas = "Far Across The Tistance And Spaces Between Us Us"

          print(datas.endswith("s"))
          运行结果:True

         6)查找字符,找到返回其索引, 找不到返回-1      

          datas = "Far Across The Tistance And Spaces Between Us"

          print(datas.find("d"))
          运行结果:26      
          datas = "Far Across The Tistance And Spaces Between Us"

          print(datas.find("D"))
         运行结果:-1

         7)format使用方式      
          datas = "you are {} yeras old,your are {}."

          print(datas.format(25,"Lily"))
          运行结果:you are 25 yeras old,your are Lily.      
          
          datas = "you are {age} yeras old,your are {name}."

          print(datas.format(name="Lucy",age=28))
          运行结果:you are 28 yeras old,your are Lucy.
        
         8)isdigit():是否整数
           print("9".isdigit())
           运行结果:True
           
           print("9a".isdigit())
           运行结果:False
        
         9)返回某字符所在字符串的索引      
          datas = "you are 22 yeras old,your are lily."

          print(datas.index("s"))
          运行结果:15


    4.python的数据类型之字典
      字典主要有两个特性:a.无序;b.key必须是唯一的。
      字典的常用功能如下:
        1)增加
         
    datas = {"name":"lily","age":"23"}
           datas["job"]="IT"
           print(datas)
           运行结果:{'age': '23', 'name': 'lily', 'job': 'IT'}

         2)修改      
          datas = {"name":"lily","age":"23"}

          datas["name"]="jack"     
          print(datas)
         运行结果:{'age': '23', 'name': 'jack'}
        3)删除      
          datas = {"name":"lily","age":"23","job":"IT"}

          datas.pop("name")
          print(datas)
          运行结果:{'age': '23', 'job': 'IT'}
          
          
          datas = {"name":"lily","age":"23","job":"IT"}

          del datas["age"]
          print(datas)
          运行结果:{'name': 'lily', 'job': 'IT'}
        
         4)查找      
          datas = {"name":"lily","age":"23","job":"IT"}
          print("name" in datas)
          运行结果:True     
          
          datas = {"name":"lily","age":"23","job":"IT"}
          print(datas.get("age"))
          运行结果:23

         5)字典的循环     
          
         
    datas = {"name":"lily","age":"23","job":"IT"}
          for i in datas:
          print(i,datas[i])
          运行结果:     

            job IT
            name lily
            age 23

    5.文件

     1) 打开文件

        打开文件时,需要指定文件路径和以哪种方式打开文件,打开后,就可以获取该文件句柄并且把它赋值给一个变量,以后通过此文件句柄对该文件操作,对文件操作结束后,要关闭文件。

        

        打开文件的主要模式如下:

          r ,只读模式【默认】

          w,只写模式【不可读;不存在则创建;存在则清空内容;】

          x, 只写模式【不可读;不存在则创建,存在则报错】

          a, 追加模式【可读;   不存在则创建;存在则只追加内容;】

          "+" 表示可以同时读写某个文件

          r+, 读写【可读,可写】

          w+,写读【可读,可写】

          x+ ,写读【可读,可写】

          a+, 写读【可读,可写】

      2)对文件进行操作

     

        文件句柄 = open('文件路径''模式'):例子  

         例子1: f = open("test.txt",mode="r",encoding="utf-8")  #以只读方式打开test.txt文件
         
         例子2:
           test.txt文件内容如下:       
              abcde
              ABCDE
              opqrst

            程序代码内容如下:      
              f = open("test.txt","r",encoding="utf-8") #以只读方式打开文件且获取文件句柄
              Files = f #把文件句柄赋值给变量Files
              a = Files.read() #读取文件内容,并且把它赋值给一个变量
              print(a)                    #输出或者打印文件内容
              运行结果:          

                abcde
                ABCDE
                opqrst

          例子3:        

            test.txt文件内容如下:       
              abcde
              ABCDE
              opqrst

            程序代码如下:       
              #!/usr/bin/env python
              # _*_ coding:utf-8 _*_
              f = open("test.txt","r",encoding="utf-8")
              Files = f
              a = Files.readline() #读取文件的一行内容
              print(a) 

              f.close()

              运行结果如下:
                abcde




     
          




          

        
      

      


           
    
    
          
     
    
    


    
    

      
      

      

        

          

          

          

          
            

          
          
          

          

          

          

            

          

          

            

          

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  • 原文地址:https://www.cnblogs.com/renyongbin/p/6287824.html
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