為什么python，當我運行我的程序時出現錯誤'預期縮進塊？

Question

我試圖讓我的程序限制用戶可以鍵入的內容。它繼續從我的代碼中返回“預期的縮進塊”錯誤。

deliverydetails = input("Is your order for delivery?\n Press 1 for delivery. Press 2 for pickup")

if deliverydetails == "1":

##    def delivery ():

    print ("Order for Delivery")
    customerfirstname = " "
    while len(customerfirstname) <3 or len(customerfirstname)>30 or customerfirstname.isalpha() != True:
    customerfirstname = input("Customer First Name: ** must be 4 characters long  + " ")                         
    while len(customersurname) < 3 or len(customersurname) > 30 or     customerfirstname.isalpha() != True:                        
    customersurname = input("Customer Surname:" + " ")
    customerstreet = input("Street name:" + " ")
    customerstreetnumber = input("Street number:" + " ")
    customercity = input("City:" + " ")
    customersuburb = input("Suburb (If none, leave blank):" + " ")
    latestOrder.append(customerfirstname)
    latestOrder.append(customersurname)
    latestOrder.append(customerstreet)
    latestOrder.append(customerstreetnumber)
    latestOrder.append(customercity)
    latestOrder.append(customersuburb)

Answer 1

Python使用縮進來分組代碼塊。 在while語句之后，你想縮進它應該在while循環中執行的下面的行。

以下是一些可能有用的其他提示： - 使用pylint檢查語法。 它將發現許多錯誤，否則您只能在運行時找到它們。 - 使用空格縮進。 不要使用標簽。 這是PEP 8風格的推薦

以下是代碼的更正版本：

deliverydetails = input("Is your order for delivery?\n Press 1 for delivery. Press 2 for pickup")

if deliverydetails == "1":
##    def delivery ():
    print ("Order for Delivery")
    customerfirstname = " "
    customersurname = " "

    while len(customerfirstname) <3 or len(customerfirstname)>30 or customerfirstname.isalpha() != True:
        customerfirstname = input("Customer First Name: ** must be 4 characters long  + " ")                         

    while len(customersurname) < 3 or len(customersurname) > 30 or     customerfirstname.isalpha() != True:                        
        customersurname = input("Customer Surname:" + " ")

    customerstreet = input("Street name:" + " ")
    customerstreetnumber = input("Street number:" + " ")
    customercity = input("City:" + " ")
    customersuburb = input("Suburb (If none, leave blank):" + " ")
    latestOrder.append(customerfirstname)
    latestOrder.append(customersurname)
    latestOrder.append(customerstreet)
    latestOrder.append(customerstreetnumber)
    latestOrder.append(customercity)
    latestOrder.append(customersuburb)

Answer 2

Python使用意圖而不是{}或begin/end ，所以例如這一行

while len(customerfirstname) <3 or len(customerfirstname)>30 or customerfirstname.isalpha() != True:

應該跟一個縮進的塊。 縮進塊可以像單行一樣短，通常你應該比while更多地縮進4個空格

旁白：將該行寫成可能更清楚

while not (3 <= len(customerfirstname) <= 30 and customerfirstname.isalpha()):

Answer 3

確保縮進作為循環一部分的行。 這是Python必須知道你想要循環的部分的唯一方法。

delivery_details = input("Is your order for delivery?\n Press 1 for delivery. Press 2 for pickup")

if delivery_details == "1":
    print "Order for Delivery"

    customer_first_name = ""
    while len(customer_first_name) < 3 or len(customer_first_name) > 30 or not customer_first_name.isalpha():
        customer_first_name = input("First name (must be 4 characters long): ")

    customer_surname       = input("Surname: ")
    customer_street        = input("Street name: ")
    customer_street_number = input("Street number: ")
    customer_city          = input("City: ")
    customer_suburb        = input("Suburb (If none, leave blank): ")

    latest_order.append(customer_first_name)
    latest_order.append(customer_surname)
    latest_order.append(customer_street)
    latest_order.append(customer_street_number)
    latest_order.append(customer_city)
    latest_order.append(customer_suburb)

為了它的價值，我為可讀性做了一些風格上的改變。 變量名稱中的一些額外間距，空白行和下划線使眼睛上的一切變得更容易。