如何在 def 函数之后运行 for 循环？

Question

我试图在 def 函数之后运行最后一个 for 循环，但它并没有像我想的那样运行。lst = [] print(lst)print('The queue is now empty...')MaxQueue = int(input('\nSet The Maximum Queue to: '))for i in range(0, MaxQueue):     print(lst)    inn = input('Enter Name: ')    lst.append(inn)  print('')   print(lst) print('The Queue is full..')   def get_answer(prompt):    while True:        answer = input(prompt)        if answer not in ('yes','no'):            answer = input(prompt)                if answer in ('yes'):            break                 if answer in ('no'):            exit()    print(get_answer('Do you want to start seriving? '))for i in range(MaxQueue,0):    print(lst)    de = input('press (enter) to serve')    print(lst.pop(0))

Answer 1

你的大问题是range函数写错了，你在较低的值之前输入了较高的值，这是错误的。与这个问题相比，您的其他问题可能是次要的，但仍然非常重要！确保始终检查您的输入以避免意外行为，例如负数或零。修复方法是：

lst = [] 

print(lst)

print('The queue is now empty...')

MaxQueue = int(input('\nSet The Maximum Queue to: '))

# A loop to ensure the user will never be able to insert a value lower than 1.

while MaxQueue <= 0:

    print('Cannot receive a length lower than 1!')

    MaxQueue = int(input('\nSet The Maximum Queue to: '))

for i in range(0, MaxQueue): 

    print(lst)

    inn = input('Enter Name: ')

    lst.append(inn)

print('\n')   

print(lst) 

print('The Queue is full..')   

def get_answer(prompt):

    while True:

        answer = input(prompt)

        if answer not in ('yes','no'):

            answer = input(prompt)        

        if answer in ('yes'):

            break         

        if answer in ('no'):

            exit()

    

print(get_answer('Do you want to start seriving? (yes/no):'))

for i in range(0, MaxQueue):

    print(lst)

    input('press (enter) to serve') # no need to save input.

    print(lst.pop(0))

Answer 2

起点超过终点的范围是空的。您get_answer还包含一些错误。

lst = [] 

print(lst)

print('The queue is now empty...')

MaxQueue = int(input('\nSet The Maximum Queue to: '))

for i in range(MaxQueue): 

    print(lst)

    inn = input('Enter Name: ')

    lst.append(inn)  

print('')   

print(lst) 

print('The Queue is full..')   

def get_answer(prompt):

    answer = None # set initial value to make sure the loop runs at least once

    while answer not in ('yes', 'no'):

        answer = input(prompt)

    if answer == 'no': 

        exit()

    

get_answer('Do you want to start serving? ')

for i in range(MaxQueue):

    print(lst)

    input('press (enter) to serve')

    print(lst.pop(0))

对于较大的程序，放在中间通常不是一个好主意exit()，因为您可能想做其他事情，所以我们可以改用布尔逻辑并做类似的事情

def get_answer(prompt):

    answer = None # set initial value to make sure the loop runs at least once

    while answer not in ('yes', 'no'):

        answer = input(prompt)

    return answer == 'yes'

    

if get_answer('Do you want to start serving? '):

    for i in range(MaxQueue):

        print(lst)

        input('press (enter) to serve')

        print(lst.pop(0))