Variable as counter

Python Help
1

my aim is simple. I want to make variable that retains its value and work as counter, say, from 1 to 500

I used the following function, but nothing happened, no error

def ch(self):
if self.ids.ch1.active:
counter = 1
counter = operator.add(counter,1)
print(counter)

2

Hi,

the way that you have your example set up it appears as if you want a function that keeps track of a variable every time that it is called (if I misunderstood this, please correct me and elaborate further).

You can do this by employing a function technique called closure functions. It works something like this:


def return_count(init):  

    counter = init      # initialize counter value

    def increment_counter():

        nonlocal counter
        counter += 1
        return counter

    return increment_counter

cnt_value = return_count(0)

# Every time that it is called, it increments the value by one
count_tracker = cnt_value()
count_tracker = cnt_value()
count_tracker = cnt_value()
count_tracker = cnt_value()

print(count_tracker)

cnt_value = return_count(0)  # Reset counter if needed

count_tracker = cnt_value()
count_tracker = cnt_value()

print(count_tracker)

As an fyi, when entering your code, please use the following format:

format_code
format_code454×506 32.1 KB

1 Like
3

why you repeated this four times

count_tracker = cnt_value()

count_tracker = cnt_value()

count_tracker = cnt_value()

count_tracker = cnt_value()

I need to increment the variable by one on button_press and use
that variable to navigate through database recordset

4

Hello,

note that it was just for demonstration purposes. You can do as you need in your code. In the following example (please make a note of that, just an example), I will show how you can keep track of the number of times two buttons have been pressed using this technique:

def return_count(init):  

    counter = init      # initialize counter value

    def increment_counter():

        nonlocal counter
        counter += 1
        return counter

    return increment_counter

cnt_value = return_count(0)

button_press_counter = 0  # Keep track of no. of times buttons
                          # were collectively pressed

def press_button1():

    global button_press_counter
    button_press_counter = cnt_value()

def press_button2():

    global button_press_counter
    button_press_counter = cnt_value()

press_button1()  # Press button 1
press_button2()  # Press button 2

print('\nTotal number of times buttons were pressed: ', button_press_counter)