zwegat: A debts calculator

zwegat is a small program I have written for my flat share to simplify debts calculations. It can read text files in a certain format and output the debts of the persons inside the text file. The debts are simplified in case person x owes person y a certain amount of money person y owes person x a certain amount of money.

Installation

Install zwegat with sudo pip install git+git://github.com/eugenkiss/zwegat.git (you need to have python and pip on your system). A command line tool zwegat will be registered.

Alternatively, simply copy the python script zwegat.py to a folder of your choice and execute it with python zwegat.py or just zwegat.py if you marked zwegat.py as executable.

Usage

Provide a filename x as a command line argument like so zwegat x.

File Format

The following exemplary segment could be the content of a correctly formatted file:

eugen;  eugen,polina,wadim; 2.70  # 01.06: Plutonium
wadim;  polina,wadim;       9.13  # 02.06: Cocaine
polina; eugen;              1.80  # 04.06: Shark fin

As you can see every line constitutes an entry. Each entry consists of three ;-separated values. The first one is the person that bought the stuff. The second value is a list of persons for whom the stuff was bought and the third value is the amount of money that the buyer (the first value) spent. Everything after # is a comment.

See also the file example.txt.

Output

So what would zwegat's output for the above segment look like? Here it is:

eugen owes
  polina 0.90

wadim owes
  eugen 0.90

polina owes
  wadim 4.57

As you can see there are no redundant debts. A currency symbol is deliberately left out.

Features

• Simplicity
• No redundant debts
• High precision arithmetic with python's Decimal library
• Okay error messages for syntax errors thanks to pyparsing

Miscellaneous

Run tests with python tests.py. You need to have nose installed.