How can I add variable name and value from `str` to a class?

Question

I have a class that I'm gonna write more variables to. I successfully use the information in it, and change information in it, but I can't find a way to make new variables. I want to use c in add_unit_group() to define both name of the new variable, and its list. I have tried using c to only define the name of the variable as well, but with no luck.

To the UnitGroups class, I want to add: a2 = ("default", unit_type)

import units

unit_type = (units.Tank1, units.Tank2, units.Tank3, units.Infantry1, units.Infantry2)

class UnitGroups:
    a = "empty"
    a1 = ("default", unit_type)
    create = "1"

def addunitgroup():
    add = ("default", unit_type)
    # UnitGroups.create = add
    for make in range(0, 10):
        if make is int(UnitGroups.create):
            print(def_name, ":   ", "make is UnitGroups.create")
            generate = UnitGroups()
        
            a = (int(UnitGroups.create) + 1)
            b = "a" + str(a)
            c = str("generate." + b + " = " + str(add))

            # UnitGroups.a = (c, " = ", str(add))
            # exec(str(UnitGroups.a))
            # UnitGroups.a2 = add
          
            UnitGroups.create = (int(UnitGroups.create) + 1)
            UnitGroups.a = "empty"

if __name__ == "__main__":
    addunitgroup()

I do not want to change the format. The variables shall be stored in that class.

Outcome that I want after first use of "addunitgroup()"

class UnitGroups:
    a = "empty"
    a1 = ("default", unit_type)
    a2 = ("default", unit_type)
    create = "2"

Outcome that I want after second use of "addunitgroup()"

class UnitGroups:
    a = "empty"
    a1 = ("default", unit_type)
    a2 = ("default", unit_type)
    a3 = ("default", unit_type)
    create = "3"

More information, just to show how I currently change the variables inside the class. I don't need help with what's added now: This load() function will change, and will also set the variables' values depending on what a file tells it to. I'll also use another function to set the values of the variables. This one will be run from a window.

def load():
    UnitGroups.a1 = ("5", units.Tank1)

Answer 1

use setattr(instance, variable_name, variable_value)

Btw: the way you have defined your class, the variables belong to the class itself, not the instance (roughly like static variables in other languages)

Answer 2

class B:
    def __init__ (self):
        self.a = []

    def add (self, value)
        self.a.append (value)

b = B ()       # Constructor __init__ calles, will make empty list inside b
b.add ('john') # Will be in b.a [0]
b.add ('mary') # Will be in b.a [1]

b2 = B ()      # Another instance, to hold different names
b.add ('bjarne') # Will be in b2.a [0]
b.add ('guido')  # Will be in b2.a [1]

etc.