django-formula-field 0.1.2

Django field for storing and evaluating formula expressions

Django Formula Field

When you want to provide placeholder columns for user to fill in based on values of the rows, you oftentimes want to have an Excel-like formula parser. This is the aim of this package, you provide a formula field and an evaluated result field.

Installation

Installation through pip: pip install django-formula-field

Getting Started

Defining an EvaluatedFormulaField is quite simple, you define a model:

from django.db import models
from django_formulafield.fields import EvaluatedFormulaField

class SampleModel(models.Model):
    formula = models.CharField(max_length=255)
    result = EvaluatedFormulaField(formula_field="formula")  

Optional parameters are:

• max_length: behind the scenes, the evaluation is stored in a CharField
• reevaluate_on_update: if it should update the evaluation when you update the record

Formula field can be a callable function defined on the model.

Evaluation

Evaluation is completely offloaded to the formulas and any FormulaErrors are raised