malaffinity 2.0.0

What is this?

Calculate the affinity (Pearson’s Correlation * 100) between a “base” user and another user.

This script is meant to be used in bulk, where one user (the “base”)’s scores are compared against multiple people, but there’s nothing stopping you from using this as a one-off.

In all files here, the “base” user refers to the user whose scores other scores will be compared to (and affinities to said scores calculated for). I don’t have a better name to describe this, so please bear with me.

In most cases, just assume that the “base” user is referring to you, or the person who will be running your script

Install

$ pip install malaffinity

Alternatively, download this repo and run:

$ python setup.py install

Or copypasta the malaffinity directory to Python:raw-latex:site-packages and install the dependencies yourself.

Dependencies

• BeautifulSoup4

• lxml

• Requests

These should be installed when you install this script, so no need to worry about them.

Usage

1. Create an instance of the MALAffinity class, providing the param base_user, and an optional round to it.

   • The base_user is the username whose scores other scores will be compared to.

   • Rounding of the final affinity is determined by the round param. To round results, provide a number of decimal places to round to. For no rounding, specify False

   • Note that the class can be initialised without the ``base_user`` param, but a ``base_user`` **MUST* be passed to the init function before any affinity calculations take place. (See example 2)*

2. Calculate affinity between the “base user” and another user by calling the calculate_affinity method with the username of the person you wish to calculate affinity with.

   • This will return a tuple, containing the affinity, and the number of shared rated anime.

3. Calculate more affinities by repeating Step 2.

Examples

Using ma as the name of the initialised class, because I can’t think of a better name that won’t shadow anything that already/will exist(s).

ma = MALAffinity("YOUR_USERNAME")

affinity, shared = ma.calculate_affinity("OTHER_USERNAME")

print(affinity)
# 79.00545465639877
print(shared)
# 82

ma = MALAffinity()

# This can be done anywhere as long as the place you're doing this from has access to `ma`.
ma.init("YOUR_USERNAME")

affinity, shared = ma.calculate_affinity("OTHER_USERNAME")

print(affinity)
# 79.00545465639877
print(shared)
# 82

ma = MALAffinity("YOUR_USERNAME", round=2)

affinity, shared = ma.calculate_affinity("OTHER_USERNAME")

print(affinity)
# 79.01
print(shared)
# 82

affinity, shared = calculate_affinity("YOUR_USERNAME", "OTHER_USERNAME")

print(affinity)
# 79.00545465639877
print(shared)
# 82

Handling exceptions

NOTE: As of v2.0.0, these exceptions are now contained in the exceptions file. Make sure to reference them properly if you’ll be going down this path. (malaffinity.exceptions.ExceptionName).

Three types of exceptions can be raised while calculating affinities:

• NoAffinityError: Raised when either the shared rated anime between the base user and another user is less than 10, or the other user does not have any rated anime.

• InvalidUsernameError: Raised when username specified does not exist.

• MALRateLimitExceededError: Raised when MAL’s blocking your request, because you’re going over their rate limit of one request every two seconds. Slow down and try again.

Not much you can do about the first two, so you’re best off giving up if you run into one of those. The third, however, rarely happens if you abide by the rate limit, but the following should happen in case it does:

• Halt the script for a few seconds. I recommend five.

• Try again.

• If you get roadblocked again, just give up. MAL obviously hates you.

This can be achieved something along these lines:

success = False

# Two attempts, then give up. Max tries can be adjusted here.
for _ in range(2):
    try:
        affinity, shared = ma.calculate_affinity("OTHER_USERNAME")

    except malaffinity.exceptions.MALRateLimitExceededError:
        time.sleep(5)

    # Yes, this is too broad, but there's no point in typing out all the exceptions.
    except:
        # Hop over to the next person.
        # You'll want to stop doing anything with this person and move onto the next,
        # so use the statement that'll best accomplish this, given the layout of your script.
        return

    # Success!
    else:
        success = True
        break

if not success:
    # See the note under `except:`. Same applies here
    return

I’m thinking about hardcoding the rate limit handling in, but I’m worried about handling cases where MAL keeps blocking you - I don’t want to run into infinite loops. I’ll look into this one day.

Feel free to use a loop though. Don’t blame me if anything bad happens because of it.

FAQ

Q: [A dumb question was here]

A: I have a bad memory and forgot floating point arithmetic was a thing.

Concerns, problems, fixes, feedback, yada yada

Contact me on Reddit or by Email, or create an issue or pull request.

The email I specified isn’t my main one, and this isn’t my main Github account, so if you do use those services, send me a message on Reddit, notifying me, otherwise you’ll probably receive a reply weeks/months after you contact me.

Legal stuff

Licensed under MIT. See `LICENSE <LICENSE>`__ for more info.

As promised, one cute cat gif coming up!