How to change the value of a variable on a button click in a bot?

Question

Python

There is a tuple in which the data is:

items = [
    'Атомик 60|70|80 см', 
    'Болевар 60|70|80 см',
]

Below is a function for handling a request from a category:

current_item = items[0]
@dp.callback_query_handler(text= 'Ecuador')
async def ecuador(call:types.CallbackQuery):
    kb = InlineKeyboardMarkup(row_width=2)
    
    next = InlineKeyboardButton(text= 'Следующий',callback_data= 'next')

    kb.add(next)

    await bot.send_photo(
    chat_id,
    photo = current_photo,
    caption='Название: '+ current_item,
    reply_markup=kb)

Then the "Next" request is processed, in which the next item from the tuple must be called ( this should also be constantly repeated cyclically until the end of the tuple! )

@dp.callback_query_handler(text= 'next')
async def row(call:types.CallbackQuery):
    kb = InlineKeyboardMarkup(row_width=2)
    
    next =InlineKeyboardButton(text= 'Следующий',callback_data= 'next')

    kb.add(next)
    await bot.send_photo(
        chat_id,
        photo = current_photo[+1],
        caption ='Название: '+ current_item[+1],
        reply_markup= kb)

caption ='Title: '+ current_item[+1]

I thought about doing this, but it didn't work out. Please help me how to do this and loop this thing

Answer 1

Make an index and pass it to callback_data, this is the parameter for this and is needed.

@dp.callback_query_handler(text= 'Ecuador')
async def ecuador(call:types.CallbackQuery):
    kb = InlineKeyboardMarkup(row_width=2)
    
    next = InlineKeyboardButton(text= 'Следующий',callback_data= 'next_1')

    kb.add(next)

    await bot.send_photo(
    chat_id,
    photo = current_photo,
    caption='Название: '+ current_item,
    reply_markup=kb)


@dp.callback_query_handler(lambda c: c.data.startswith('next_'))
async def send_next_item(call: types.CallbackQuery):
    next_index = int(call.data.split('_')[-1])
    kb = InlineKeyboardMarkup(row_width=2)
    next = InlineKeyboardButton(text = 'Следующий',  callback_data = f'next_{next_index+1}')
    kb.add(next)
    await bot.send_photo(
        chat_id,
        photo = items[next_index],
        caption ='Название: '+ items[next_index],
        reply_markup= kb)

Plus, don't forget to check if the index matches the length of the list, but it's still a list, not a tuple.