搜索文本文件的字符串

Question

我相當落後於我的課程，我停留在發展我的代碼任務2 我的程序必須允許用戶輸入一系列的條形碼，搜索文本文件的代碼，然後如果找到，則詢問用戶他們希望購買的產品的數量。最後它應該打印收到的總產品和總價格。

但我的代碼不會當我在我的文件中搜索代碼的工作，它只是不斷循環，並要求用戶重新輸入其條碼。

這是到目前爲止我的代碼：

loop=True 
while loop==True: 
    print ("------STOCK LIST------") 
    print ("a - Place an order by barcode") 
    print ("b - Place an order by product name") 
    print ("x - Exit") 

    task=input("Please make your selection\n") 
    if task.lower()=="a": 
     print("------STOCK FILE LOADING------") 
     myfile=open("barcode.txt", "r") #this opens the text file 
     details=myfile.readlines() #reads the file and stores it as the variable 'details' #myfile.close() #closes the file 
     while True: 
      digits=input("Please enter your GTIN-8 code\n") 
      if len(digits) > 8 or len (digits) < 8: #if the digits are longer or shorter than 8 digits, the code is not accepted 
       print("Please enter a GTIN-8 code\n") 
      else: 
       break #if the code is the correct length, the loop ends 
       for line in details: 
        if digits in line: 
         productline=line 
         myfile=open("receipt.txt", "r") #opens receipt file 
         myfile.writelines("\n" + "+") 
         quantity=input("How much of the product do you wish to purchase?\n") 
         itemsplit=itemline.split(' ') #seperates into different words 
         price=float(itemsplit[2]) #price is 
         total=(price)*(quantity) #this works out the price 
         myfile.writelines("Your total spent on this product is: " +str("£:,.2f)".format(total)+"\n")) 
        else: 
         break 

如果你能幫助我，我將非常感激因爲沒有我的同學都會幫助我，如果是這樣，你可以保持的代碼，因爲我很簡單不是最好的編碼？

Answer 1

我做的GCSE課程，自己所以我現在體會與課程的難度。儘管如此，小心地要求人們提供代碼 - 我敢肯定，這可能會讓你在某些規範中失去資格（儘管我沒有和你一樣）。

我看到你的代碼兩個主要問題：

1.縮進是不正確（如果我理解正確的話，你現在要做什麼）

我想應該是這樣的：

while loop==True: 
    print ("------STOCK LIST------") 
    print ("a - Place an order by barcode") 
    print ("b - Place an order by product name") 
    print ("x - Exit") 
    task=input("Please make your selection\n") 
    if task.lower()=="a": 
     print("------STOCK FILE LOADING------") 
     myfile=open("barcode.txt", "r") #this opens the text file 
     details=myfile.readlines() #reads the file and stores it as the variable 'details' #myfile.close() #closes the file 
     while True: 
      digits=input("Please enter your GTIN-8 code\n") 
      if len(digits) > 8 or len (digits) < 8: #if the digits are longer or shorter than 8 digits, the code is not accepted 
       print("Please enter a GTIN-8 code\n") 
      else: 
       break #if the code is the correct length, the loop ends 
     for line in details: 
      if digits in line: 
       productline=line 
       myfile=open("receipt.txt", "r") #opens receipt file 
       myfile.writelines("\n" + "+") 
       quantity=input("How much of the product do you wish to purchase?\n") 
       itemsplit=itemline.split(' ') #seperates into different words 
       price=float(itemsplit[2]) #price is 
       total=(price)*(quantity) #this works out the price 
       myfile.writelines("Your total spent on this product is: " +str("£:,.2f)".format(total)+"\n")) 
      else: 
       break 

現在，如果用戶輸入密碼正確，你的整個while循環一旦代碼被驗證的突破。該程序沒有時間執行for循環中的下一步。

2.第二if聲明

if len(digits) > 8 or len (digits) < 8: #if the digits are longer or shorter than 8 digits, the code is not accepted 
    print("Please enter a GTIN-8 code\n") 
else: 

這可以變得更好。代替它打破了while僅環如果輸入的密碼是正確的長度你可以寫一個新的if聲明。 您當前的聲明會要求我在每次出錯時重新輸入代碼兩次，而不是每次輸入錯誤的時候都會詢問一次。

我即將開始處理您的其他問題。

祝你好運！