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I am quite new to scripting, and here is my first code I wrote. The goal of the code is to extract a parent ID based on a child ID. I would appreciate some constructive criticism and aggressive checkup. The codes works and does what it's supposed to do. But how can I make it more pythonic? more passionate?

import codecs



import numpy as np

import pandas as pd





def import_file(path):

    '''imports the .csv files as a pandas dataframe

    Args:

        path (csv file): Takes in the path for the .csv file



    Returns:

        Returns a pandas dataframe

        '''

    with codecs.open(path, "r", encoding='utf-8', errors='ignore') as fdata:

        df = pd.read_csv(fdata)

    return df





def appends_address_before_name(file):

    '''Appends the address before the name ID name

    Returns:

        Returns the file, with address appened to column name.

        '''

    file['ID'] = [address + str(col) for col in file['ID']]

    return file





def create_parent_name(file, column_name: str):

    '''This will create a parent name based on the ID column



    Args:

        file: takes in the dataFrame created from appends_address_before_name function



        column_name: Takes in the column name where the parent name

        will be extracted from.The logic is to split it on the last dot.

        [[parentname].[+ childname]]



    Returns:

        Returns a pandas dataframe with a new column called parentID

        '''

    file['parentID'] = [

        x.rsplit('.', 1)[0] if '.' in x else x[:-1] for x in file[column_name]

    ]



    return file





address = 'New_Jersey_'

file_1 = import_file(r'C:humans.csv')

file_2= appends_address_before_name(file=file_1)

file_3= create_parent_name(file=file_2 , column_name = 'ID')



print(file_3)

The input CSV is a column of values separated with decimal places like the following:

ID



99.99.9

100.42.3

Example output

parentID



New_Jersey_99.99

New_Jersey_100.42

Furthermore, I feel like the way I am passing variables between the functions at the end of the code seems quite basic and terrible. What can I improve in the above code and how can I improve it ?

A screenshot of the code working

You should decide if your functions modify the object they receive or if the return a modified object. Doing both is just asking for disaster. After your code has finished, file_1, file_2 and file_3 are all identical.

The usual convention is to return None (implicitly or explicitly) if you mutate any of the inputs. In the rest of this answer I have decided to mutate the inputs.

Besides that, pandas is most effective if you use its vectorized functions. For columns with strings, it has a whole lot of methods which are vectorized. You can access them with df.col_name.str. You can find some examples in the documentation.

Your appends_address_before_name function could be simplified a lot because string addition is vectorized:

def appends_address_before_name(file):

    file["parentID"] = address + file["parentID"]

    file["ID"] = address + file["ID"]

And your create_parent_name function could be:

def create_parent_name(file, column_name: str):

    file["parentID"] = file[column_name].str.split(".").str[:-1].str.join(".")

With a csv file like this:

ID

99.99.9

100.42.3

101

This produces

df = import_file(file_name)

create_parent_name(df, 'ID')

appends_address_before_name(df)

print(df)

#                     ID           parentID

# 0   New_Jersey_99.99.9   New_Jersey_99.99

# 1  New_Jersey_100.42.3  New_Jersey_100.42

# 2       New_Jersey_101        New_Jersey_

Note that the order of the calls has changed, so that ids without a . are handled correctly.

As for general structure:

• Seeing docstrings is very nice (I omitted them here for brevity)


• Python has an official style-guide, PEP8. It recommends writing x = some_thing(a=3), so surround equal signs with spaces when assigning but not when setting keyword arguments.


• You should wrap the main calling code in a if __name__ == "__main__" guard.