CODEWITHSUNDEEP
pythonfunctionvariablesscopereturn-value
Pyderman
Pyderman

Reputation: 16219

Accessing all variables declared in a function without duplicating code

Given:

PICKLE_FILENAME_INSTRUCTION_IDS = 'pickled_instruction_ids.txt'

def compare_instruction_id_list_with_baseline(baselineidspicklefile):
    baseline_ids = load_pickled_ids(baselineidspicklefile)
    current_main_url_content = get_page_content(main_url_test)
    root = lh.fromstring(current_main_url_content)
    current_ids = get_instruction_ids(root)
    diff = [id for id in current_ids if id not in baseline_ids]
    return diff

where baselineidspicklefile is the baseline of ids (a list), pickled.

Later on in the code, I do a check of diff, and if it's not empty, I do something with the new ids (current_ids). Now though, I realise that if diff is non-empty, I also wish to overwrite the baseline ids with the new list of diffs via pickle, making it the new baseline.

current_ids is local to this function though. So I can't just call pickle.dumps() on it from the main section of the program. I'd rather not return both diff and current_ids from the function. And obviously I'd rather not make current_ids global. What are my options for accessing both variables?

Note: This is a general issue I have - I also encounter it when using urllib2 e.g in a function that does the following:

response = urllib2.urlopen(url)
content = response.read()

I typically return content so I can do things like lxml.html.fromstring(content), but then I realise that a later point in the program will need to access response, and I'm stuck because that's not what I've returned.

Upvotes: 1

Views: 32

Answers (1)

zondo
zondo

Reputation: 20336

You can use the builtin locals() function:

PICKLE_FILENAME_INSTRUCTION_IDS = 'pickled_instruction_ids.txt'

def compare_instruction_id_list_with_baseline(baselineidspicklefile):
    baseline_ids = load_pickled_ids(baselineidspicklefile)
    current_main_url_content = get_page_content(main_url_test)
    root = lh.fromstring(current_main_url_content)
    current_ids = get_instruction_ids(root)
    diff = [id for id in current_ids if id not in baseline_ids]
    return locals()

You can then use all variables defined in compare_instruction_id_list_with_baseline by using the return value and then in brackets a string that defines the variable you want. For example, return_value = compare_instruction_id_list_with_baseline(...) diff = return_value['diff'].

Upvotes: 4

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