Python While循环中的用户输入

下面是我的代码，它应该接受3个正整数作为用户的输入。然而，它并没有按照预期工作

def getPositiveNumber(prompt):
    timeUnits = (input("This is the numnber of time units to simulate > "))
    numAtoms = (input("How many atoms should we simulate ? "))
    radBeaker = (input("The radius of the beaker is ? "))
    while True:
         if timeUnits.isnumeric() and numAtoms.isnumeric() and radBeaker.isnumeric():
         print("All your values are integers")
         break

     else:
         timeUnits = input("This is the number of units to simulate. >")
         numAtoms = input("How many atoms should we simulate ? ")
         radBeaker = input("The radius of the beaker is ? ")
return timeUnits, numAtoms, radBeaker

这导致在放置了最初的3个输入之后再次询问输入，但是如果我放置了非数字，我希望它在初始部分之后再次询问

试试这个：

def getPositiveNumber(prompt):
  timeUnits = None
  numAtoms = None
  radBeaker = None
  while True:
    timeUnits = input('This is the numnber of time units to simulate > ')
    numAtoms = input('How many atoms should we simulate ? ')
    radBeaker = input('The radius of the beaker is ? ')
    if timeUnits.isnumeric() and numAtoms.isnumeric() and radBeaker.isnumeric():
      print 'All your values are integers'
      break
  return (timeUnits, numAtoms, radBeaker)

---

写三个几乎相同的代码片段来读取三个整数是没有意义的。您需要一个获得一个数字的函数。您可以调用此函数三次，或者，实际上，根据需要调用任意次数：

def get_positive_int(prompt):
    while True:        
        possibly_number = input(prompt + "> ")
        try:
            number = int(possibly_number)
        except ValueError: # Not an integer number at all
            continue
        if number > 0: # Comment this line if it's ok to have negatives
            return number

函数依赖于这样一个事实：由

int（）

识别的任何字符串都是有效的整数。如果是，则将号码返回给呼叫者。如果不是，则由保持循环运行的

int（）

引发异常

例如：

>>> get_positive_int("This is the number of units to simulate")
This is the number of units to simulate> ff
This is the number of units to simulate> -10
This is the number of units to simulate> 25
25

---

您可以分离测试以检查输入是否是函数的正整数

def is_positive(n):
    """(str) -> bool
    returns True if and only if n is a positive int
    """
    return n.isdigit() 

接下来，您可以创建一个函数来请求一个正整数。为此，请避免使用

str.isnumeric

方法，因为该方法也会为浮点返回

True

。而是使用

str.isdigit

方法

def request_input(msg):
    """(str) -> str
     Return the user input as a string if and only if the user input is a positive integer
    """
    while True:
        retval = input(msg)
        if is_positive(retval):
            return retval
        else:
            print("Please enter a positive integer")

request\u input

将永远循环，直到收到一个正整数。这些简单的模块可以组合起来实现您想要的。在您的特殊情况下：

def get_user_inputs(prompt):
    time_units = request_input("This is the number of time units to simulate > ")
    num_atoms = request_input("How many atoms should we simulate ? ")
    rad_breaker = request_input("The radius of the beaker is ? ")
    return time_units, num_atoms, rad_breaker

---

如果需要整数，可以使用int函数。这将强制用户输入一个整数。发布的代码无效。第二，一次只选一个号码，在正确选择前一个号码之前不要选下一个号码。你试过了吗？（提示：否）@Joey试试这个解决方案，告诉我它是否对你有效？？