pyvin: Parsing VIN number

Question

Context

Same code for decoding a column with Vehicle Identification Numbers, for one of the libraries i'm getting an error.

Code

import pandas as pd
from vininfo import Vin # COUNTRY AND BRAND
from pyvin import VIN # MODEL AND YEAR


db = pd.DataFrame("VIN": ["3N6PD23W5ZK911765", "MNTACUD40Z0000632", "3N6DD23T9ZK874454"])  # VIN EXAMPLE


db["COUNTRY"] = db["VIN"].map(lambda x: Vin(x).country)  # PARSES OK AND RETURNS COUNTRY
db["BRAND"] = db["VIN"].map(lambda x: Vin(x).manufacturer)  # PARSES OK AND RETURNS BRAND

db["MODEL"] = db["VIN"].map(lambda x: VIN(x).Model)  # ERROR
db["YEAR"] = db["VIN"].map(lambda x: VIN(x).ModelYear)  # ERROR

ERROR

AttributeError: 'list' object has no attribute 'Model'
or
AttributeError: 'list' object has no attribute 'ModelYear'

Question

I don't ask for a complete solution because the problem is pretty specific but at this point i'm feeling insecure and any tip is welcome.

Is x in db["YEAR"] = db["VIN"].map(lambda x: VIN(x).ModelYear) equal to a single string or is it passing a list to the function?

Answer 1

Let's break the problem in pieces. First, the db is a pandas.DataFrame object. The db["VIN"] is a pandas.Series object, as you probably know. You can also verify it with

In [19]: type(db["VIN"])
Out[19]: pandas.core.series.Series

Then, the pandas.Series.map function that you are using takes arg as argument that can be type of dict or a function (or Series). You give it a function. Then, this function is called for each of the values of the series db["VIN"]. Let's see what that is.

# first value OK. Maybe?
In [23]: VIN("3N6PD23W5ZK911765")
Out[23]: <pyvin.pyvin.DecodedVIN at 0x2ef77ea5550>

# second value not OK
In [24]: VIN("MNTACUD40Z0000632")
Out[24]: []

So, for some reason, the VIN returns a list. Why is that? It is because the pyvin.VIN does not recognize the input. If you add error handling, you'll see:

In [26]: import pyvin

In [27]: VIN("MNTACUD40Z0000632", error_handling=pyvin.RAISE)

...
c:\python\python 3.8.6-64\lib\site-packages\pyvin\utils.py in _compare_check_digit(vin, remainder)
     92     if check_digit != rem_val:
     93         msg = 'Invalid check digit! %s does not match computed val %s' % (check_digit, rem_val)
---> 94         raise VINError(msg)
     95     logger.debug("%s check [OK]")
     96

VINError: Invalid check digit! 0 does not match computed val 5

I would suspect that either the VIN code is incorrect, the pyvin has a bug, or the underlying service (NHTSA API) does not recognize the VIN code.