計算在一個文件中輸入查詢值的平均值，代碼產生錯誤的輸出

Question

「」「」

num = 3 
try:  #set an exception in case of a file Error 

    while num >=0: '''read in values and place them in a file''' 
     value = int(input("Enter values: ")) 
     my_file = open('my_data.txt', 'w+') 
     my_file.write(str(value)) 
     numbers = my_file.readlines() 
     num -=1 
    my_file.close() 

except IOError: 
    print('FILE FAILURE') 

'''iterate to find the sum of the values in a file''' 
total = 0 
    for ln in numbers: 
     total += int(ln) 

'''Calculate the average''' 
avg = total/len(numbers) 
    print("The average is %d"%(avg))#FIXME: does not calculate average 

Answer 1

您正在打開的文件寫入「這個簡單的程序將使用文件計算平均」，然後從讀它，並將其分配給一個變量numbers。但是，這個變量不是一個列表，雖然你在做for ln in numbers時將它當作列表對待。

此外，你應該結束寫入基於我如何理解你的代碼\n

到文件中的行，你想：

• 獲取用戶輸入，並寫入到文件
• 從文件，讀取數字
• 從數計算平均

有一個statistics模塊，功能mean，它將爲您執行計算部分。其餘的，你可以（應該）像上面的三個項目符號結構，像這樣：

from statistics import mean 

def inputnumbers(itterations, filename): 
    with open(filename, 'w') as openfile: 
     while itterations > 0: 
      try: 
       value=int(input("value->")) 
      except ValueError: 
       print('Numbers only please') 
       continue 
      openfile.write(str(value) + '\n') 
      itterations -= 1 

def getaveragefromfile(filename): 
    numbers = [] 
    with open(filename, 'r') as openfile: 
     for line in openfile.readlines(): 
      numbers.append(int(line.replace('\n',''))) 
    return mean(numbers) 

def main(): 
    filename = r'c:\testing\my_data.txt' 
    itterations = int(input('how many numbers:')) 
    inputnumbers(itterations, filename) 
    average = getaveragefromfile(filename) 
    print(average) 

if __name__ == '__main__': 
    main()