python - Python while 循环

Question

我在 python 3 中有这段代码，用于检查输入错误，但我需要确定输入是否为整数，如果不是则打印错误消息。

谁能帮我找出我的while循环中的代码。谢谢

price = 110;

ttt = 1;

while price < 0 or price > 100:

    price = input('Please enter your marks for Maths:');
    ttt =ttt +1;
    if ttt >= 2:
        print( 'This is an invalid entry, Please enter a number between 0 and 100')

Answer 1

使用该int()函数转换为整数。这将在无法进行转换时引发 ValueError ：

try:
    price = int(price)
except ValueError as e:
    print 'invalid entry:', e

Answer 2

你可能想要这样的东西，它会捕获价格是否为整数以及是否在 0 到 100 之间，如果满足这些条件，则中断循环。

while True:
    price = raw_input('Please enter your marks for Maths:')
    try:
        price = int(price)
        if price < 0 or price > 100:
            raise ValueError
        break
    except ValueError:
        print "Please enter a whole number from 0 to 100"

print "The mark entered was", price

或者，由于您的可能值数量很少，您还可以执行以下操作：

valid_marks = [str(n) for n in range(101)]
price = None
while price is None:
    price = raw_input('Please enter your marks for Maths:')
    if not price in valid_marks:
       price = None
       print "Please enter a whole number from 0 to 100"

Answer 3

首先，使用raw_input代替input.

此外，ttt在您的输入之前放置检查，以便正确显示错误：

price = 110;
ttt = 1;
while price < 0 or price > 100:
    if ttt >= 2:
        print 'This is an invalid entry, Please enter a number between 0 and 100';
    price = raw_input('Please enter your marks for Maths:');
    ttt = ttt +1;

Answer 4

我会说最简单的事情是做而不是做

price=int(price)

做

price=int(110)