比較簡單的資料結構，直接貼程式碼

stack=[]

def pushit ():
    stack.append(raw_input('enter new string:').strip())

def popit ():
    if len(stack)==0:
        print 'Cannot pop from an empty stack'
    else:
        print 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()
            except (EOFError,KeyboardInterrupt,IndexError):
                choice='q'

            print '\nYou 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()