（二）colletions模块总结，跳出3重循环代码总结，替换文件中某一字段代码总结

# -*- coding:utf-8 -*-from collections import Counter, OrderedDict, defaultdict, namedtuple, deque# Counter是对字典类型的补充，用于追踪值的出现次数。# ps：具备字典的所有功能 + 自己的功能print("Counter".center(50, "-"))c = Counter('abcdeabcdabcaba')print(c.most_common(3))print(''.join(c.elements()))print(''.join(sorted(c.elements())))print(''.join(sorted(c)))print(c['b'])c['b'] -= 3print(c['b'])print(''.join(c.elements()))# orderdDict是对字典类型的补充，他记住了字典元素添加的顺序# 见博客http://blog.csdn.net/liangguohuan/article/details/7088304，写的已经足够好了print("orderDict".center(50, "-"))d1 = {}d1['a'] = 'A'd1['b'] = 'B'd1['c'] = 'C'd2 = OrderedDict()d2['a'] = 'A'd2['b'] = 'B'd2['c'] = 'C'print(d1 == d2)d3 = OrderedDict()d3['b'] = 'B'd3['a'] = 'A'd3['c'] = 'C'print(d2 == d3)# Python collections.defaultdict() 与 dict的使用和区别# http://www.pythontab.com/html/2013/pythonjichu_1023/594.htmlprint('defaultdict'.center(50, '-'))values = [11, 22, 33, 44, 55, 66, 77, 88, 99, 90]my_dict1 = defaultdict(list)for value in values:    if value > 66:        my_dict1['k1'].append(value)    else:        my_dict1['k2'].append(value)print(my_dict1)my_dict2 = {}for value in values:    if value > 66:        my_dict2.setdefault('k1', []).append(value)    else:        my_dict2.setdefault('k2', []).append(value)print(my_dict2)print(my_dict1['x'])print(my_dict1)s = 'mississippi'd = defaultdict(int)for k in s:    d[k] += 1print(list(d.items()))# 根据nametuple可以创建一个包含tuple所有功能以及其他功能的类型。# 博客地址http://blog.csdn.net/wukaibo1986/article/details/8188906print("nametuple".center(50, "-"))Bob = ('bob', 30, 'male')Jane = ('Jane', 29, 'female')for people in[Bob, Jane]:    print("%s is %d years old %s" % people)Person = namedtuple('Person', 'name age gender')print('Type of Person:', type(Person))Bob = Person(name='Bob', age=30, gender='male')print('Representation:', Bob)Jane = Person(name='Jane', age=29, gender='female')print('Field by Name:', Jane.name)for people in[Bob, Jane]:    print("%s is %d years old %s" % people)# 双向队列(deque)# 一个线程安全的双向队列print("deque".center(50, "-"))q = deque('abaacdefgh')print(q)q.append('x')print(q)q.appendleft(3)print(q)print(q.count('a'))q.extend(['a','b'])print(q)q.extendleft(['a', 'b', 'c'])print(q)print(q.pop())print(q.popleft())print(q)q.remove(3)print(q)q.reverse()print(q)# 单向队列,是先进先出（FIFO），使用了queue模块，其中单项和双项队列均有。# Queue是一个队列的同步实现。队列长度可为无限或者有限。# 可通过Queue的构造函数的可选参数maxsize来设定队列长度。如果maxsize小于1就表示队列长度无限。import queueprint("Queue".center(50, "-"))q = queue.Queue(maxsize = 2)q.put(1)q.put(2)# q.put('a', block=False)  # 如果队列当前已满且block为True(默认)，put()方法就使调用线程暂停,直到空出一个数据单元。如果block为False，put方法将引发Full异常。# q.put_nowait(3)  #  相当q.put(3, block=False)print(q.get())print(q.get())# print(q.get(block=False))  # 调用队列对象的get()方法从队头删除并返回一个项目。可选参数为block，默认为True。如果队列为空且block为True，get()就使调用线程暂停，直至有项目可用。如果队列为空且block为False，队列将引发Empty异常。# print(q.get(timeout=2))  # 等待2秒后仍然为空则报异常,常用于多线程

输出

---------------------Counter----------------------[('a', 5), ('b', 4), ('c', 3)]bbbbecccaaaaaddaaaaabbbbcccddeabcde41becccaaaaadd--------------------orderDict---------------------TrueFalse-------------------defaultdict--------------------defaultdict(<class 'list'>, {'k1': [77, 88, 99, 90], 'k2': [11, 22, 33, 44, 55, 66]}){'k1': [77, 88, 99, 90], 'k2': [11, 22, 33, 44, 55, 66]}[]defaultdict(<class 'list'>, {'k1': [77, 88, 99, 90], 'k2': [11, 22, 33, 44, 55, 66], 'x': []})[('i', 4), ('s', 4), ('p', 2), ('m', 1)]--------------------nametuple---------------------bob is 30 years old maleJane is 29 years old femaleType of Person: <class 'type'>Representation: Person(name='Bob', age=30, gender='male')Field by Name: JaneBob is 30 years old maleJane is 29 years old female----------------------deque-----------------------deque(['a', 'b', 'a', 'a', 'c', 'd', 'e', 'f', 'g', 'h'])deque(['a', 'b', 'a', 'a', 'c', 'd', 'e', 'f', 'g', 'h', 'x'])deque([3, 'a', 'b', 'a', 'a', 'c', 'd', 'e', 'f', 'g', 'h', 'x'])3deque([3, 'a', 'b', 'a', 'a', 'c', 'd', 'e', 'f', 'g', 'h', 'x', 'a', 'b'])deque(['c', 'b', 'a', 3, 'a', 'b', 'a', 'a', 'c', 'd', 'e', 'f', 'g', 'h', 'x', 'a', 'b'])bcdeque(['b', 'a', 3, 'a', 'b', 'a', 'a', 'c', 'd', 'e', 'f', 'g', 'h', 'x', 'a'])deque(['b', 'a', 'a', 'b', 'a', 'a', 'c', 'd', 'e', 'f', 'g', 'h', 'x', 'a'])deque(['a', 'x', 'h', 'g', 'f', 'e', 'd', 'c', 'a', 'a', 'b', 'a', 'a', 'b'])----------------------Queue-----------------------12

跳出三重循环（一般也没人会去跳出三重循环。。。算是一种技巧吧）：

# -*- coding:utf-8 -*-# don't make your programs have too many layers# if you do have that many layers, try to use the funciton feature.break_flag1 = Falsebreak_flag2 = Falsebreak_flag3 = Falsewhile not break_flag1:    print('the first layer is running...')    option = input(">>>[b:back, q:quit, c:continue]")    if option == 'q':        break_flag1 = True    elif option == 'b':        break_flag1 = True    else:        break_flag2, break_flag3 = False, False  # continue    while not (break_flag2 or break_flag1):        print('the second layer is running...')        option = input(">>>[b:back, q:quit, c:continue]")        if option == 'b':            break_flag2 = True        elif option == 'q':            break_flag1 = True        else:            break_flag3 = False  # continue        while not (break_flag1 or break_flag2 or break_flag3):            print('the third layer is running...')            option = input(">>>[b:back, q:quit, c:continue]")            if option == 'b':                break_flag3 = True            elif option == 'q':                break_flag1 = True

修改文件中某个字段方法（建立一个新文件，把旧文件的内容一行一行写到新文件里去即可）：

old.txt:

yangkaialexnihaook

将alex替换为ALEX LI...

import os# 替换原文件中的某个字段,方法是新写一个文件f = open('old.txt', 'r')f_new = open('new.txt', 'w')for line in f:    if line.startswith('alex'):        new_line = line.replace('alex', "ALEX LI...")        f_new.write(new_line)    else:        f_new.write(line)f.close()f_new.close()os.rename('new.txt', 'old.txt')