爲什麼代碼只能用於前三次迭代？

Question

請問爲什麼代碼只爲前三次迭代提供最小值和最大值的正確輸出？

我前三次迭代的輸出正常工作。最小和最大變量鎖定到這些值，並不會根據新輸入進行更新。 其餘的計算（總和，數量和平均）工作正常。

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count= 0 
sum=0 
average=0 
minimal=None 
maximum=None 
while True: 
    number=raw_input("Enter a number: ") 
    try: 
     if (number=='done'): 
      break 
     else: 
      count=count+1 
      sum=sum+float(number) 
      if minimal==None: 
       minimal=float(number) 
       maximum=float(number) 
      else: 
       minimal=min(number,minimal) 
       maximum=max(number,maximum) 
       print maximum 
       print minimal 
      average=sum/count 
      #print ("Calc done") 
    except: 
     print ("Invalid input") 
print("Count: %d, Sum=%d and Average=%d" %(count,sum,average)) 
print("smallest number is %d" %minimal) 
print("largest number is %0.2f" %float(maximum)) 

Answer 1

下面的代碼有效。請參閱差異：

count= 0 
sum=0 
average=0 
minimal=None 
maximum=None 
while True: 
    number=raw_input("Enter a number: ") 
    try: 
     if (number=='done'): 
      break 
     else: 
      count=count+1 
      sum=sum+float(number) 
      if minimal==None: 
       minimal=float(number) 
       maximum=float(number) 
      else: 
       minimal=min(float(number),minimal) 
       maximum=max(float(number),maximum) 
       print maximum 
       print minimal 
      average=sum/count 
      #print ("Calc done") 
    except: 
     print ("Invalid input") 
print("Count: %d, Sum=%d and Average=%d" %(count,sum,average)) 
print("smallest number is %d" %minimal) 
print("largest number is %0.2f" %float(maximum)) 

Answer 2

在你的函數調用min(number,minimal)和max(number,maximum)，你是不是鑄造number爲float。這必須完成，因爲minimal和maximum是浮動類型。

嘗試用float(number)替換參數number，像這樣：

minimal=min(float(number),minimal) 
maximum=max(float(number),maximum)