Python雖然循環沒有結束

Question

我有一些而循環問題。我的目標是如果用戶輸入一個負值3次，while循環就會結束。問題是，當我到達第三條消息時，它並不以「milesLoop」結尾，因爲它應該是 （我嘗試使用一個循環，但我想使用多個循環進行測試） 這可能是一個容易解決的問題，但我卡住了。

這是Python代碼：

__author__ = 'MichaelCorbett' 
import sys 

print('Michael Corbett converter ') 
print('\n') 

milesLoop = 1 
fhietLoop = 1 
gallonLoop = 1 
poundsLoop = 1 
inchesLoop = 1 

while milesLoop == 1: 

    miles = float(input('What\'s up Will, how many miles do you wish to convert to Kilometers? ')) 
    if miles < 0: 
     print('This converter does not accept negeative values. Try again!') 

     miles = float(input('What\'s up Will, how many miles do you wish to convert to Kilometers? ')) 
     if miles < 0: 
      print('This converter does not accept negeative values. Try again') 

      miles = float(input('What\'s up Will, how many miles do you wish to convert to Kilometers? ')) 
      if miles < 0: 
       print('This converter does not accept negeative values. Program is Terminated') 
       milesLoop = 2 


       while fhietLoop == 1: 

        Fheit = float(input('What temperature is it outside in Fahrenheit? ')) 
        if Fheit < 0 and Fheit > 1000: 
         print('This converter does not accept negeative values.') 

         Fheit = float(input('What temperature is it outside in Fahrenheit? ')) 
         if Fheit < 0 and Fheit > 1000: 
          print('This converter does not accept negeative values.') 

          Fheit = float(input('What temperature is it outside in Fahrenheit? ')) 
          if Fheit < 0 and Fheit > 1000: 
           print('This converter does not accept negeative values. Program is Terminated') 
           fhietLoop = 2 


          while gallonLoop == 1: 

           gallon = float(input('How many gallons are you trying to convert? ')) 
           if gallon < 0: 
            print('This converter does not accept negeative values.') 

            gallon = float(input('How many gallons are you trying to convert? ')) 
            if gallon < 0: 
             print('This converter does not accept negeative values.') 

             gallon = float(input('How many gallons are you trying to convert? ')) 
             if gallon < 0: 
              print('This converter does not accept negeative values. Program Terminated') 
              gallonLoop = 2 


             while poundsLoop == 1: 

              pounds = float(input('How many pounds would you like to convert? ')) 
              if pounds < 0: 
               print('This converter does not accept negeative values.') 

               pounds = float(input('How many pounds would you like to convert? ')) 
               if pounds < 0: 
                print('This converter does not accept negeative values.') 

                pounds = float(input('How many pounds would you like to convert? ')) 
                if pounds < 0: 
                 print('This converter does not accept negeative values. Program Terminated') 
                 poundsLoop = 2 


                while inchesLoop == 1: 

                 inches = float(input('How many inches would you like to convert? ')) 
                 if inches < 0: 
                  print('This converter does not accept negeative values.') 

                  inches = float(input('How many inches would you like to convert? ')) 
                  if inches < 0: 
                   print('This converter does not accept negeative values.') 

                   inches = float(input('How many inches would you like to convert? ')) 
                   if inches < 0: 
                    print('This converter does not accept negeative values. Program Terminated') 
                    inchesLoop = 2 



                   # Calculations 

                   kilometers = miles * 1.6 
                   celsius = int((Fheit - 32) * 5/9) 
                   liters = gallon * 3.9 
                   kilograms = pounds * .45 
                   centimeters = inches * 2.54 

                   # Output 

                   print('\n') 
                   print(miles, ' miles is ', kilometers, ' Kilometers') 
                   print('Its is ', celsius, 'Celsius outside.') 
                   print(gallon, ' gallons is ', liters, ' liters') 
                   print(pounds, ' pounds is ', kilograms, ' kilograms') 
                   print(inches, ' inches is ', centimeters, ' centimeters') 

Answer 1

def get_float(prompt): 
    while True: 
     try: 
      return float(input(prompt)) 
     except: 
      print "Thats not a number!" 


def get_positive_number(prompt,tries=3): 
    for i in range(tries): 
     result = get_float(prompt) 
     if result >= 0: return result 
     print "Sorry Negative not allowed %d/%d"%(i,tries) 

while True: 
    result = get_positive_number("How Many Gallons?") 
    if result is None: 
     print "OK DONE" 
     break 
    print "Convert %0.2f Gallons"%(result) 

Answer 2

__author__ = 'MichaelCorbett' 
import sys 

def myLoop(question, tries = 0): 
    while True: 
     if tries == 3: 
      sys.exit() 
     user_in = float(input(question)) 
     if user_in < 0: 
      print('This converter does not accept negeative values. Try again!') 
      tries += 1 
     else: 
      return user_in 

print('Michael Corbett converter\n') 

miles = myLoop('What\'s up Will, how many miles do you wish to convert to Kilometers?') 
Fheit = myLoop('What temperature is it outside in Fahrenheit?') 
gallon = myLoop('How many gallons are you trying to convert?') 
pounds = myLoop('How many pounds would you like to convert?') 
inches = myLoop('How many inches would you like to convert?') 

# Calculations 

kilometers = miles * 1.6 
celsius = int((Fheit - 32) * 5/9) 
liters = gallon * 3.9 
kilograms = pounds * .45 
centimeters = inches * 2.54 

print('\n{0} miles is {1} Kilometers'.format(miles, kilometers)) 
print('Its is {0} Celsius outside.'.format(celsius)) 
print('{0} gallons is {1} liters'.format(gallon, liters)) 
print('{0} pounds is {1} kilograms'.format(pounds, kilograms)) 
print('{0} inches is {1} centimeters'.format(inches, centimeters))