用戶輸入錯誤值后如何制作python回圈程式？

為班級做作業，我需要用戶輸入 1 到 500 之間的值，如果用戶輸入的錯誤值超過 3 次，則程式應該關閉。如果用戶需要重試，我也會遇到使程式回圈的問題

這是我到目前為止所擁有的。

    flour = 2.75
    baking_soda = 1
    baking_powder = 0.5
    butter = 1
    sugar = 1.5
    egg = 1
    vanilla = 1
    makes = 48
    
    cookies = float(input('Enter number of cookies: '))
    
    count = 0
    
    flour = (cookies * flour) / makes
    baking_soda = (cookies * baking_soda) / makes
    baking_powder = (cookies * baking_powder) / makes
    butter = (cookies * butter) / makes
    sugar = (cookies * sugar) / makes
    egg = (cookies * egg) / makes
    vanilla = (cookies * vanilla) / makes
    
    while (cookies >=1 and cookies <=500):
        print("You need "   str(round(flour,2))  
          " cups of flour, "   str(round(baking_soda,2))  
          " teaspoons of baking soda, "   str(round(baking_powder,2))  
          " teaspoons of baking powder, "   str(round(butter,2))  
          " cups of butter, "  str(round(sugar,2))  
          " cups of sugar, "   str(round(egg,2))  
          " eggs and "   str(round(vanilla,2))  
          " teaspoons of vanilla.")
        break
count=0
    while (cookies <1 or cookies >500):
        count =1
        cookies = float(input('Enter valid number: '))
        if (count>=3):
            print("I will now close.")
            exit()

uj5u.com熱心網友回復：

這是現在的樣子，我認為這就是答案，因為它不會再給我帶來任何問題。

flour = 2.75
baking_soda = 1
baking_powder = 0.5
butter = 1
sugar = 1.5
egg = 1
vanilla = 1
makes = 48

cookies = int(input('Enter number of cookies from 1 to 500: '))
count=0
while (cookies <1 or cookies >500):
    count =1
    cookies = int(input('Enter valid number: '))
    if (count>=3):
        print("I will now close.")
        exit()
while (cookies >=1 and cookies <=500):
    flour = (cookies * flour) / makes
    baking_soda = (cookies * baking_soda) / makes
    baking_powder = (cookies * baking_powder) / makes
    butter = (cookies * butter) / makes
    sugar = (cookies * sugar) / makes
    egg = (cookies * egg) / makes
    vanilla = (cookies * vanilla) / makes
    
    print("You need "   str(round(flour,2))  
      " cups of flour, "   str(round(baking_soda,2))  
      " teaspoons of baking soda, "   str(round(baking_powder,2))  
      " teaspoons of baking powder, "   str(round(butter,2))  
      " cups of butter, "  str(round(sugar,2))  
      " cups of sugar, "   str(round(egg,2))  
      " eggs and "   str(round(vanilla,2))  
      " teaspoons of vanilla.")
    break

uj5u.com熱心網友回復：

您有正確的想法，但您需要根據回圈的流程進行思考。要求用戶輸入總是很棘手，您總是希望在進行任何計算或作業之前嘗試驗證輸入。

有幾件事你似乎已經明白，你至少需要問一次。您可以在如下所示的單個回圈中完成所有這些操作。

我基本上是在創建一個無限回圈，只有在你出錯 5 次時才會停止。請注意，除非用戶至少一次做對，否則回圈將不會進行計算。請注意，在現實世界中，您將為用戶提供一個隨意退出的機會。嘗試以某種方式實作它，以便如果用戶輸入字母q，則程式結束。

請注意，我留下了一些小錯誤供您修復。如果你能解決它，你就會得到回圈的句柄。嘗試輸入 2 個 cookie，然后輸入 48 個 cookie。看看這個數字怎么沒有意義，有幾種方法可以解決這個問題，但關鍵是要理解為什么會出錯。

flour = 2.75
baking_soda = 1
baking_powder = 0.5
butter = 1
sugar = 1.5
egg = 1
vanilla = 1
makes = 48

count = 0

while (True):
    cookies = float(input('Enter number of cookies: '))
    
    if (cookies < 1 or cookies > 500):
        print('Invalid response, the number must be between 1 and 500')
        count  = 1
        
        if count > 4:
            print("I will now close.")
            break

        continue
    
    flour = (cookies * flour) / makes
    baking_soda = (cookies * baking_soda) / makes
    baking_powder = (cookies * baking_powder) / makes
    butter = (cookies * butter) / makes
    sugar = (cookies * sugar) / makes
    egg = (cookies * egg) / makes
    vanilla = (cookies * vanilla) / makes
    
    print("You need "   str(round(flour,2))  
      " cups of flour, "   str(round(baking_soda,2))  
      " teaspoons of baking soda, "   str(round(baking_powder,2))  
      " teaspoons of baking powder, "   str(round(butter,2))  
      " cups of butter, "  str(round(sugar,2))  
      " cups of sugar, "   str(round(egg,2))  
      " eggs and "   str(round(vanilla,2))  
      " teaspoons of vanilla.")
 

標籤：Python 循环 托尼

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