Question

尝试做一个布尔测试循环，其中用户需要输入10到1000之间的数字，包括10和1000，他们需要保持这个循环，直到他们输入正确的数字然后我将完成else语句

我试过了：

while (num_years < 10) and (num_years > 1000):  # boolean test , note ==  (= will give you an error!)
    print("Your input must be 10 and 1000")
    input("Enter number of years to simulate (currently " + str(num_years) + "): ")  
else:
    print()

和此：

while (num_years == range(10, 1000)):  # boolean test , note ==  (= will give you an error!)
    print("Your input must be 10 and 1000")
    input("Enter number of years to simulate (currently " + str(num_years) + "): ")  
else:
    print()

Answer 1

您可以尝试这样的事情，因为它还会检查用户是否输入了有效的数字：

while True:
  number = input("Enter number of years to simulate (10-1000): ")
  try:
    years = int(number)
    if years >= 10 and years <= 1000: 
      break
    else:
      print("Your input must be between 10 and 1000 inclusive")
  except ValueError:
    print("That's not an int!")

print("Simulating %d years..." % years)

使用示例：

Enter number of years to simulate (10-1000):  asd
That's not an int!
Enter number of years to simulate (10-1000):  5
Your input must be between 10 and 1000 inclusive
Enter number of years to simulate (10-1000):  245
Simulating 245 years...

试试here!

Answer 2

好的，首先：

(num_years < 10) and (num_years > 1000)

这总是假的，因为一个数字不能同时小于10且大于1000。

其次

num_years == range(10, 1000)

将永远不会有效，因为左边有（可能）整数，右边有generator。

但是你可能会尝试这样的事情：

possible_years = range(10,101)
num_years = 50
while num_years in possible_years:  # or 9 < num_years < 100
    print("Your input must be 10 and 1000")
    entered_years = input("Enter number of years to simulate (currently " + str(num_years) + "): ")
    num_years = int(entered_years) # remeber to check if entered_years is int before this line!
else:
    print()

但是仍有一个问题，您需要检查用户是否输入了整数。

Answer 3

您永远不会更改num_years的值，因此条件永远不会改变。修复你的布尔逻辑：

num_years = 0
while (num_years < 10) or (num_years > 1000):
    print("Your input must be 10 and 1000")
    num_years = int(input("Enter number of years to simulate (currently {}): ".format(num_years)))
else:
    print()

但是，如果您需要覆盖非数字值然后使用try: except: pass块，则假设有人输入了数字：

try:
    num_years = int(input("Enter number of years to simulate (currently {}): ".format(num_years)))
except ValueError:
    pass

注意：=是赋值而非等同性测试。使用in来测试值是list还是range。

Answer 4

您需要做的是使用while循环来检查输入是否有效。如果不是，它将再次循环。此外，您永远不会将输入分配给变量。

n = None
while n is None or not 10 <= n <= 1000:

    if n is not None: # Only happens if it's not the first input
        print('Invalid number, please try again')

    try:
        n = int( input('Enter number of years to simulate (10-1000): ') ) # Convert the
                                                                          # string to an int
    except:
        pass

print( 'Simulating {} years...'.format(n) )

一旦输入有效数字，它将继续并说模拟，因为

not 10 <= n <= 1000

将评估为假。

您可以通过以下链接进行试用：https://repl.it/FftK/0

Answer 5

n =无 n是无或不是10 <= n <= 1000：

if n is not None: # Only happens if it's not the first input
    print('Invalid number, please try again')

try:
    n = int( input('Enter number of years to simulate (10-1000): ') ) # Convert the
                                                                      # string to an int
except:
    pass

打印（＆＃39;模拟{}年......＆＃39; .format（n））

我想返回一个＆＃34; duo＆＃34;中的顶级元素的数量。名单

5 个答案: