Converts Swedbank CSV format into a CSV table format which is easier for automated processing.

swedbank-csv.py

#!/bin/python3

# Converts Swedbank CSV format into a CSV table
# format which is easier for automated processing.
#
# Usage:
#
# 1. Save file as swedbank-csv.py and open terminal in folder location.
# 2. In termial: python3 swedbank-csv.py -i <path to source CSV>
# 3. For more info, run: python3 swedbank-csv.py --help
#
# Example:
#
# Date,Beneficiary/Payer,Details,Amount,Currency,Transaction type,Balance
# 01.01.2019,,Opening balance,,EUR,AS,41.7
# 06.01.2019,Janis Pipars,Parskaitijums,-10.0,EUR,IZP,
# 10.01.2019,,Kartes mēneša maksa 12.2019,-1.41,EUR,KOM,
# 31.01.2019,,Closing balance,,EUR,LS,20.0
#
# Works with Swedbank Latvia CSV format as at 23 Oct 2020.
#
# Author: Pavel Diatchenko <diatche@gmail.com>
# Licence: MIT

import csv
import argparse
from pathlib import Path

parser = argparse.ArgumentParser(
    description=(
                'Converts Swedbank CSV format into a CSV table '
                'format which is easier for automated processing.\n\n'
                'Works with Swedbank Latvia CSV format as at 23 Oct 2020.\n\n'
                'Author: Pavel Diatchenko <diatche@gmail.com>\n'
                'Licence: MIT'
    )
)
parser.add_argument(
    '-i',
    '--source',
    type=str,
    required=True,
    help='Source CSV file path.',
)
parser.add_argument(
    '-o',
    '--destination',
    type=str,
    help='Destination CSV file path.',
)
parser.add_argument(
    '-s',
    '--suffix',
    type=str,
    help='Destination CSV file suffix. If destination file is ommited, this suffix is added to the source file name',
)
parser.add_argument(
    '-d',
    '--delimiter',
    type=str,
    help='Source CSV column delimiter.',
)
parser.add_argument(
    '--verbose',
    dest='verbose',
    action='store_true',
    help='Verbose mode.',
)

parser.set_defaults(
    suffix='-parsed',
    delimiter=';',
    verbose=False,
)
args = parser.parse_args()
verbose = bool(args.verbose)

source_path = Path(args.source).expanduser()
if verbose: print(f'source_path: "{source_path}"')

destination_path = ''
if not bool(args.destination):
    # Polyfill with_stem (new in Python 3.9)
    def with_stem(p, stem):
        ext = p.suffix
        return p.with_name(f'{stem}{ext}')
    
    if verbose: print(f'suffix: "{args.suffix}"')
    destination_path = with_stem(source_path, source_path.stem + args.suffix)
else:
    destination_path = Path(args.destination).expanduser()
if verbose: print(f'destination_path: "{destination_path}"')

delimiter = args.delimiter
if verbose: print(f'delimiter: "{delimiter}"')

BALANCE_KEY = 'Balance'
AMOUNT_KEY = 'Amount'
DEBIT_CREDIT_KEY = 'Debit/Credit'
DEBIT = 'D'
CREDIT = 'K'
TYPE_KEY = 'Transaction type'
BALANCE_TYPES = {'AS', 'LS'}
REMOVE_TYPES = set(['K2'])
INPUT_HEADERS = ['Client account', 'Row type', 'Date', 'Beneficiary/Payer', 'Details', AMOUNT_KEY, 'Currency', DEBIT_CREDIT_KEY, 'Transfer reference', TYPE_KEY, 'Reference number', 'Document number', '']
OUTPUT_HEADERS = ['Date', 'Beneficiary/Payer', 'Details', AMOUNT_KEY, 'Currency', TYPE_KEY, BALANCE_KEY]

with open(source_path, newline='') as source:
    reader = csv.reader(source, delimiter=delimiter, quotechar='"')
    destination_path.touch()
    with open(destination_path, 'w', newline='') as destination:
        writer = csv.writer(destination, delimiter=',', quotechar='"')
        if verbose: print('begin')
        for i, row in enumerate(reader):
            if i == 0:
                assert row == INPUT_HEADERS, 'Unexpected input headers'
                writer.writerow(OUTPUT_HEADERS)
                continue
            row_dict = {}
            for key, val in zip(INPUT_HEADERS, row):
                row_dict[key] = val

            # filter types
            if row_dict[TYPE_KEY] in REMOVE_TYPES:
                continue

            # map amount sign
            amount = float(str(row_dict[AMOUNT_KEY]).replace(',', '.'))
            debit_credit = row_dict[DEBIT_CREDIT_KEY]
            is_debit = debit_credit == DEBIT
            is_credit = debit_credit == CREDIT
            if not is_debit and not is_credit:
                continue
            if is_debit:
                amount = -amount

            # map balance
            balance = ''
            if row_dict[TYPE_KEY] in BALANCE_TYPES:
                balance = amount
                amount = ''
            else:
                balance = ''
            
            out_dict = {
                AMOUNT_KEY: amount,
                BALANCE_KEY: balance
            }
            outrow = []
            outval = None
            for key in OUTPUT_HEADERS:
                if key in out_dict:
                    outval = out_dict[key]
                elif key in row_dict:
                    outval = row_dict[key]
                outrow.append(outval)
            writer.writerow(outrow)
            if verbose: print(outrow)
        if verbose: print('end')