RPG equip cost calculator

calculate.py

#!/usr/bin/env python3

"""Usage: python3 calculate.py "path/to/file"
PRE: input file format example. csv-like file:
unitary cost, moltiplicator (optional), name or descriptor

Scrolls
12,5    5x Mage Armor scroll (CL1)
12,5    2x Shield scroll (CL1)
37,5    2 Shield scroll (CL3)
12,5    2x Reduce Person Scroll (CL1)
12.5    Enlarge Person Scroll (CL1)
12.5    Silent Image (CL1)
75    Protection from Good (CL3)
75    2x See Invisibility (CL3)
75    Gust of Wind (CL3)
75    2x Invisibility (CL3)
75    1x Disguise Other (CL3)
75    1x Alter Self (CL3)
75    2x Cat’s Grace (CL3)
75    Bear’s Endurance (CL3)
187.5    1x Clay Skin (CL5)
187.5 1x Shrink Item (CL5)
187.5 1x Fly (CL5)
187.5 1x Haste (CL5)
350    1x Invisibility, Greater (CL7)

Wands
750     Wand
"""

import argparse
import re


def remove_trailing_x(arg):
    """Return an `arg`'s copy without the trailing final x."""
    if arg[-1] == 'x':
        return arg[:-1]
    return arg


def convert_to_float_or_1(arg):
    """Return `float(arg)`, or 1 if the cast fails."""
    try:
        value = float(arg)
        return value
    except ValueError:
        return 1.0


# Match for records, form '132 1x item name and stuff'
re_record = re.compile(r'\d*[\.,]?\d+\s+\d*x?[ \t]*.*|\d+')

# Match for sections, normal text
re_section = re.compile(r'[\w \t\d]+')

# Parse filename, CLI argument
parser = argparse.ArgumentParser()
parser.add_argument("file")
args = parser.parse_args()

try:
    with open(args.file, "r") as f:
        value = f.readlines()
except FileNotFoundError:
    print('File "%s" does not exist' % args.file)
    exit(-1)

tot = 0.0  # Total
tots = {}  # Total for each category
key = ''   # Default Key

for line in value:

    if len(line) > 0.0:
        match_record = re_record.match(line)
        match_section = re_section.match(line)

        if match_record:
            # print('Matched record: ' + match_record.group())  # Debugging
            line = line.split()
            line[0] = line[0].replace(',', '.')
            line[1] = remove_trailing_x(line[1])

            if key != '':  # Not in the default case
                arg_1 = convert_to_float_or_1(line[1])
                tots[key] += float(line[0]) * arg_1
            tot += float(line[0]) * arg_1

        elif match_section:
            # print('Matched section: ' + match_section.group())  # Debugging
            key = line.rstrip()
            tots[key] = 0.0

# Total
print()  # Beautify
result = 'Total: %.2f' % (tot)
print(result)
print('-' * len(result))  # Beatify
print()  # Beatify

# Categories, sorted by value (descending order)
for key, value in sorted(tots.items(), key=lambda x: x[1], reverse=True):
    if value > 0:
        print('%s: %.2f' % (key, value))