从 MySql 输入中删除 {}

Question

I am using a MySql stored procedure, get_list, to populate a ttk.Combobox

my_number = tk.StringVar()
cb=ttk.Combobox(top_frame,width=25,textvariable=my_number)
cb['values']=db.get_list()
cb.grid(row=1,column=4)

It works fine, except the results are bracketed by {} .

RESULTS: {Smith, John}

What I want: Smith, John

How do I get rid of the beginning and ending {} ?

Answer 1

The problem is that the database query is returning a list of rows, where each row is a list with a single column. What you need for the values option is a list of strings.

So, the simple solution is to use a list comprehension to convert each row to a string. Something like this should work:

values = [row[0] for row in db.get_list()]
cb['values'] = values

Since I can't run your code I can't say for sure. Regardless, the root of the problem is that you're passing a list of lists (or tuples) and tkinter requires a list of strings.

Because internally tkinter uses curly braces for lists, it's adding the curly braces to preserve the nature of the data you're passing in. It's up to you to convert the data you get back from db.get_list() into a list of strings.

Answer 2

Bryan, I inserted the two line of code you suggested, but I am still getting value surrounded by {}. Lots I don't understand, but I believe, never know for sure, that the MySql procedure is returning a string. Here is the MySQL code:

CREATE DEFINER=`root`@`localhost` PROCEDURE `get_list`()
BEGIN
    SELECT concat(last_name,', ', first_name) as last_first
      FROM volunteers
    ORDER BY
      last_first;
END


my_number = tk.StringVar()
cb = ttk.Combobox(top_frame, width=25, textvariable=my_number)
values = [row[0] for row in db.get_list()]
cb['values'] = db.get_list()
cb.grid(row=1, column=4)

thanks for your persistence.