使用计数器的 While 循环答案

【问题标题】：While Loop using a counter使用计数器的 While 循环
【发布时间】：2019-09-10 09:02:19
【问题描述】：

我试图让它在用户使用 while 循环和中断函数输入客人姓名的地方，当循环结束时，我希望列表按编号顺序打印出来，例如

詹姆斯
卡尔
丽莎
布莱恩

但是对于可以输入多少个名字没有设置限制

我已经尝试过 while true 循环，但是当我使用

print("\nMy Wedding Attendees are: "  "\n", extra)

它只打印出我的婚礼参加者是：但不是名字

print("Now enter the names of other people you are inviting to your wedding\n")
counter = 1
extra = input("Guest's Name(or press Enter to quit): ")
while counter >= 1:       #WHILE loop
    extra = input("Guest's Name(or press Enter to quit): ")
    counter = counter + 1
    if extra == "":
        break     #break Statement
print("\nMy Wedding Attendees are: "  "\n", extra)

我希望它看起来像

我的婚礼参加者是： 1.名称 2.名称 3.名称 4. 姓名

【问题讨论】：

请在您的代码中添加缩进。
您实际上并没有存储extra 输入，因此在循环之后它将始终是空字符串。考虑存储要打印的响应。

标签： python python-3.x

【解决方案1】：

您可以使用以下代码完成它：

counter = 1
extra=[' ']  #initializing a random value for extra at the start.
a=[]

while extra != '':     
     extra = input("Guest's Name(or press Enter to quit): ")
     a.append(extra)
     counter += 1

print("\nMy Wedding Attendees are: "  "\n")
a.pop(-1) #removing the '' from the list, as we do not need it 

j=1
for i in range(0,len(a)):
    print(str(j)+'. '+a[i])
    j+=1

【讨论】：

【解决方案2】：

您基本上会在每次循环迭代中覆盖extra，这就是不打印名称的原因。我建议您将所有客人姓名（带有指定的柜台）收集在一个列表中，然后打印出来。例如：

print("Now enter the names of other people you are inviting to your wedding\n")

counter = 0

guest_names = list()

while True:
    guest_name = input("Guest's name (or press Enter to quit): ")
    if guest_name == "":
        break
    counter += 1
    guest_names.append(str(counter) + ". " + guest_name)  # record all names
print("\nMy wedding attendees are:\n" + " ".join(guest_names))

输出将是（在 Jupyter notebook 中测试）：

Now enter the names of other people you are inviting to your wedding

Guest's name (or press Enter to quit): John
Guest's name (or press Enter to quit): Marie
Guest's name (or press Enter to quit): Sebbe
Guest's name (or press Enter to quit): David
Guest's name (or press Enter to quit): 

My Wedding Attendees are:
1. John 2. Marie 3. Sebbe 4. David

如果你想在名称之间换行，你应该使用带有join()的换行分隔符：

print("\nMy wedding attendees are:\n" + "\n".join(guest_names))

在这种情况下，输出将是：

My wedding attendees are:
1. John
2. Marie
3. Sebbe
4. David

希望对你有帮助。

【讨论】：

【解决方案3】：

如 cmets 中所述，您不会将数据保存在任何地方。我已经使用 enumerate 编写了一个代码，它消除了您对 count 变量的需求。您可以在文档中阅读有关它的信息。代码是

代码

print("Now enter the names of other people you are inviting to your wedding\n")

attendes = []  # Keep names of guest

flag = True  # To keep loop control

while flag is True:
    name = input("Guest's Name(or press Enter to quit): ")
    if name is not "":  # If not empty then add to list
        attendes.append(name)
    else:  # stop the loop
        flag = False

print("\nMy Wedding Attendees are: "  "\n")

# No need for count when using enumerate
for no, name in enumerate(attendes, 1):
    print('{}. {}'.format(no, name), end=', ')
    # If you don't want the , in output just use end=' '

输出

Now enter the names of other people you are inviting to your wedding

Guest's Name(or press Enter to quit): A
Guest's Name(or press Enter to quit): B
Guest's Name(or press Enter to quit): C
Guest's Name(or press Enter to quit): D
Guest's Name(or press Enter to quit):

My Wedding Attendees are:

1. A, 2. B, 3. C, 4. D,

【讨论】：