python实现队列 FIFO

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先进先出的队列，比较简单的数据结构，直接贴代码

queue=[]def enQ():    queue.append(raw_input(' enter new string: ').strip())def deQ():    if len(queue)==0:        print 'cannot pop from an empty queue'    else:        print queue.pop(0)def viewQ():    print queueCMDs = {'e': enQ, 'd' : deQ, 'v' : viewQ}def showmenu():    pr="""    (E)nqueue    (D)equeue    (V)iew    (Q)uit    Enter choice:    """    while True:        while True:            try:                choice = raw_input(pr).strip()[0].lower()            except (EOFError, KeyboardInterrupt, IndexError):                choice = 'q'            print '\nYou picked: [%s]' % choice            if choice not in 'devq':                print 'Invalid option. try again'            else:                break        if choice == 'q':            break        CMDs[choice]()if __name__ == '__main__':    showmenu()

参考自python核心编程p148

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