python模拟队列和堆栈（列表练习）

##################################queue##########################################!/usr/bin/env python'use list as a queue'#define a void list as a void queuequeue = []#define in queue functiondef enQ():    queue.append(raw_input('Enter New String: ').strip())#define out queue functiondef deQ():    #judge queue whether viod    if len(queue) == 0:        print('Can not pop from an empty queue!')    else:        print('Removed' ,queue.pop(0))#define show queue functiondef viewQ():    print(queue)#define a dictionary to chose opration functioncmds = {'e':enQ,'d':deQ,'v':viewQ}#define a funtion to show menudef showMenu():    pr = '''    (E)nqueue    (D)equeue    (V)iew    (Q)uit        Enter choice:'''    #double while circle make program always run    while True:        while True:            try:                #use to print menu information and get valid choice number(no space, just one bit , lower)                choice = raw_input(pr).strip()[0].lower()            except(EOFError,KeyboardInterrupt,IndexError):                #if get a invalid value,return 'q'                choice = 'q'                            print('You picked: %s '% choice)            if choice not in 'devq':                print('Invalid option, try again!')            else:                break        if choice == 'q':            break        #call functions by dictionary        cmds[choice]()#main functionif __name__ == '__main__':    showMenu()         ##################################stack###################################### #!/usr/bin/env python'this program use list as a stack'stack = []def pushit():    'input stack '    stack.append(raw_input('Enter New Strings: ').strip())def popit():    'output stack'    if len(stack) == 0:        print('Can not pop from an empty stack!')    else:        print('removed [',stack.pop(),']')def viewStack():    print(stack)CMDs = {'u': pushit, 'o': popit, 'v': viewStack}def showMenu():    pr = '''    p(U)sh    p(O)p    (V)iew    (Q)uit    Enter Choice: '''    while True:        while True:            try:                choice = raw_input(pr).strip()[0].lower()                print(choice)            except(EOFError.KeyboardInterrupt,IndexError):                choice = 'q'            print('you picked: %s ' % choice)             if choice not in 'uovq':                print('Invalid option, try again')            else:                break        if choice == 'q':            break        CMDs[choice]()if __name__ == '__main__':    showMenu()