Python学习---基础篇

###打开文件并打印：

 #!/usr/bin/python3

 f = open('F://myproject/test.txt', encoding='utf-8',mode='r')
 content = f.read()
 print(content)
 f.close()

###使用os模块的walk() 遍历文件目录：

 #!/usr/bin/python3
 import os
 import os.path

 dir = "f:/project/"                         

 for dirpath,dirnames,filenames in os.walk(dir):
     for dirname in  dirnames:
         print("dirpath is:" + dirpath)
         print("dirname is:" + dirname)

     for filename in filenames:
         print ("dirpath is:" + dirpath)
         print ("filename is:" + filename)
         print ("the full name of the file is:" + os.path.join(dirpath,filename))

遍历目录下的每一个文件夹(包含它自己), 产生3-元组 (dirpath, dirnames, filenames)【文件夹路径, 文件夹名字, 文件名】

### 冒泡排序

 #!/usr/bin/python3
 # coding:utf-8

 def bubbleSort(nums):
     for i in range(len(nums)-1):
         for j in range(len(nums)-i-1):
             if nums[j] > nums[j+1]:
                 nums[j], nums[j+1] = nums[j+1], nums[j]
     return nums
 nums = [9,2,45,67,32,7,87,28,6]
 print(bubbleSort(nums))

range() 函数可创建一个整数列表，range(1,10)表示从[1, 2, 3, 4, 5, 6, 7, 8, 9]

### 插入排序

 #!/usr/bin/python3
 # coding:utf-8

 def insert_sort(lists):
     count = len(lists)
     for i in range(1, count):
         key = lists[i]
         j = i - 1
         while j >= 0:
             if lists[j] > key:
                 lists[j + 1] = lists[j]
                 lists[j] = key
             j -= 1
     return lists

### 选择排序

 #!/usr/bin/python3
 # coding:utf-8

 def select_sort(lists):
     count = len(lists)
     for i in range(0, count):
         cnt = i
         for j in range(i + 1, count):
             if lists[cnt] > lists[j]:
                 cnt = j
         lists[cnt], lists[i] = lists[i], lists[cnt]
     return lists

### 输出乘法表

  print('\n'.join(['\t'.join(['%d * %d = %d'%(y,x,x*y) for y in range(1,x+1)])for x in range(1,10)]))

join() 方法用于将序列中的元素以指定的字符连接生成一个新的字符串。‘\t’.join(parameter) 表示用'\t'连接元素序列parameter中的各元素

### 删除列表重复元素

  list = [1,1,2,3,6,8,9,6,6,7,8]
2  set(list)

### 反转字符串

 str = "string"
 str[::-1]

### 切割字符串

 #!/usr/bin/python3
 # coding:utf-8

 str="1:a$2:b$3:c$4:d"
 str_list=str.split('$')
 res={}
 for l in str_list:
     key,value=l.split(':')
     res[key]=value
 print(res)