How can I access variables defined within if/elif statements at the end of the parent Python function?

Question

How can I reference variables defined within if/elif statements further on in the parent Python (3.6) function?

The below is a mock-up of my code - I am trying to 'print' or 'work with' variables defined in each 'if' and 'elif' block below, at the end of the function which contains the if/elif statements that the variables are defined within, however I get an unresolved reference error in Pycharm and the following Python error when I run the code:

    UnboundLocalError: local variable 'a1_summary' referenced before assignment

I am relatively new to Python and coding and don't understand where I am going wrong as I expect that as the variables are defined within the same function then they should be 'visible' to the print statement at the end of the function...

Is this a case where global variables should be used?

def Process_Data(incoming_data):

      if incoming_data.count(',') == 2:
         data_summary = incoming_data.split(',')
         a1_summary, b1_summary = data_summary[0], data_summary[1]

      elif incoming_body.count(',') == 3:
           data_summary = incoming_data.split(',')
           a2_summary, b2_summary, c2_summary = data_summary[0], data_summary[1], data_summary[2]

      print(a1_summary, b1_summary, a2_summary, b2_summary, c2_summary )

      else:
           pass

Update

I was trying to keep the question simple but may have confused things as I am trying to use the if/elif statements within a function that process messages from a RabbitMQ message queue - I need to process messages based on the number of commas in the respective message and assign the parts of the message to variables and then aggregate the parts from each message received and processed by the if/elif statements into one array so that I can then pass this to another function later on in my program.

I may be going wrong in thinking that each time the function receives incoming_data which matches either the if or elif statement - any previous or new data that matches the other condition will still be held as a variable within the function e.g. I am thinking that the function holds variables from both the if/elif blocks and only updates any new data processed by the corresponding logic statement...

Answer 1

Thanks to all those who commented on my question, you have given me food for thought however I seem to have found a work around/solution to the problem as follows:

I created a config.py file and defined variables in it, e.g.

config.py

a1_summary = ""
b1_summary = ""

a2_summary = ""
b2_summary = ""
c2_summary = ""

Then in my 'main' python script file, I imported 'config' and referenced the variables it contains using the prefix 'config.' in my function - the updated code from my original example is shown below:

import config
...

def Process_Data(incoming_data):

  if incoming_data.count(',') == 2:
     data_summary = incoming_data.split(',')
     config.a1_summary, config.b1_summary = config.data_summary[0], config.data_summary[1]

  elif incoming_body.count(',') == 3:
       data_summary = incoming_data.split(',')
       config.a2_summary, config.b2_summary, config.c2_summary = config.data_summary[0], config.data_summary[1], config.data_summary[2]

  print(config.a1_summary, config.b1_summary, config.a2_summary, config.b2_summary, config.c2_summary )

  else:
       pass

This now allows me to aggregate the values from each of the if/elif statements into the print statement at the bottom of the code.

I think using a class as suggested by thebjorn above may be the prefered way of doing this however as I am new to python/coding this is a little beyond my understanding at present and the solution above allows me to do what I need to for the moment.

I realise I need to learn more about classes and intend to do so as I think using these would be more elegant and remove the need for an external config.py file.

I hope this may be useful to those who are currently in a similar position to myself.