elif 语句出现语法错误

Question

I'm trying to set up a menu. In the menu, the user is able to pick which option to take and then add or delete items from a list. I'm having trouble with the syntax in my elif statement. it's saying there is a syntax error and highlighting the second elif. I'm not sure what the problem is.

choice = int(input('Enter your choice: '))
if choice !=0:
    display_menu()
elif choice == 1:
    add_value = float(input('Add value: ')
elif choice == 2:
    delete_value_by_value = float(input('Which value would you like to delete? 

Answer 1

You forgot a closing parenthesis in the fifth line:

add_value = float(input('Add value: '))
#                                     ^

Also, the seventh line is not properly terminated. You want:

delete_value_by_value = float(input('Which value would you like to delete?'))
#                                                                         ^^^

Answer 2

delete_value_by_value = float(input('Which value would you like to delete?'))
                                                                 missing--^^^

Answer 3

Keep in mind that Python can only tell you where it stopped being able to make sense of your program, it can't tell you where you actually made the mistake.

In this case you have left parentheses open on the preceding line. Python allows expressions to span multiple lines when parentheses are open, so it is taking the elif as part of the parenthesized expression. elif is invalid in an expression, so Python raises an error there. But the "real" mistake (ie, the one that goes with your intended meaning) is the missing parenthesis.

Just be glad you're not programming in good old UCSD Pascal in the 1980s. Every program had to end with a period. If it didn't, you got an error message pointing to some random place inside your program, leaving you mystified.

Answer 4

I'd suggest searching for a good IDE that highlights syntaxes to minimize simple errors and typos. Personally I like Eclipse with PyDev.