json - Why is my python function printing out {}Main and not just Main?

Question

I am using a function to grab my data from a json file and print it to a tkinter combo box, for some reason the first word always has {} in front of it. My json data doesn't have it so why does it appear in my output?

    with open('profiles.txt', 'r') as file:
        profiles = json.load(file)
        for profile in profiles:
            add_profile = profile['profile_name']
            profiles_select['values'] = (profiles_select['values'], add_profile)

Values is also preset to have nothing in it so the values container code looks like this: profiles_select = ttk.Combobox(new_task_frame1, width=10, values=[])

Here is the json sample data:

[
    {
        "profile_name": "Main",
        "first_name": "Michael ",
    },
    {
        "profile_name": "Test",
        "first_name": "Michael ",
    }
]

This is what i expect to show up in my tkinter combo box :

Main
Test

This is what actually outputs

{}Main
Test

Answer 1

Question: Why is my python function printing out '{}Main' and not just 'Main'?

• Initalizing profiles_select['values']

  profiles_select = ttk.Combobox(new_task_frame1, width=10, values=[])
  

  This results, widget internal, to: '', tcl uses: '{}'

---

• Adding options

  profiles_select['values'] = (profiles_select['values'], add_profile)
  

  You take the internal value ''and a new option 'Main', which results in ('', 'Main').

---

• How tkinter shows the Listbox options

  Your two options:

  {}Main  
  Test
  

  More than two options:

  profiles_select['values'] = ('{{{} Main} Test} Test2', 'Test3')
  
  {{{} Main} Test} Test2
  Test3
  

---

Conclusion, don't update options using:
profiles_select['values'] = (profiles_select['values'], add_profile)

---

Solution: Create your sequence first and assign it in whole once.

with open('profiles.txt', 'r') as file:
    profiles = json.load(file)

    options = []
    for profile in profiles:
        options.append(profile['profile_name'])

    profiles_select['values'] = options