stack = []def push_it(): item = input('item to push: ') stack.append(item) def pop_it(): if stack: print("from stack popped %s" % stack.pop()) def view_it(): print(stack) def show_menu(): cmds = { '0': push_it, '1': pop_it, '2': view_it} # 将函数存入字典 prompt = """(0) push it (1) pop it (2) view it (3) exit Please input your choice(0/1/2/3): """ while True: # input()得到字符串，用strip()去除两端空白，再取下标为0的字符 choice = input(prompt).strip()[0] if choice not in '0123': print('Invalid input. Try again.') continue if choice == '3': break cmds[choice]() if __name__ == '__main__': show_menu()