Formula

Simple formula-like expression solver.

Parses formula into a reverse polish notation. Evaluates parsed to get result.

Installation

pip install px-formula

Usage

Uou can calculate formulas with different operators, and function calls. But it's not a python code, that executes - only simple maths expressions.

from px_formula import Formula, defaults


formula = Formula(
  # Can change operators:
  operators=defaults.operators,
  # And available functions:
  functions=defaults.functions,
)

parsed = formula.parse('2/8+45*6+var1')
# > ['2', '8', '/', '45', '6', '*', '+', 'var1', '+']

# You can evaluate any formula you have/stored easily:
formula.evaluate(parsed, {'var1': 5})
# > 275.25

# Or in one shot:
formula('2/8+abs(45*6)+var1', {'var1': 5})
# > 275.25

Supported

Operators:

• ~ - Inverse
• ! - Not
• ** - Pow
• * - Multiply
• / - Divide
• // - Floor divide
• % - Modulo
• + - Plus
• - - Minus
• | - Bitwise Or
• & - Bitwise And
• ^ - Bitwise Xor
• <= - LTE
• >= - GTE
• == - Equals
• < - LT
• > - GT

Functions:

• abs - operator.abs
• sin - math.sin
• cos - math.cos
• tan - math.tan
• exp - math.exp
• abs - abs
• trunc - Removes decimal part
• round - round
• hypot - math.hypot
• all - all(True, False, True) -> False
• any - any(True, False, False) -> True

Changelog

All notable changes to this project will be documented in this file.

The format is based on Keep a Changelog, and this project adheres to Semantic Versioning.

[Unreleased]

[0.1.0]

Fixed

• Issue: Stored stack turns empty after first evaluation.

[0.1.0]

Initial version.