src/pyutils/typez/rate.py

   1 #!/usr/bin/env python3
   2
   3 # © Copyright 2021-2022, Scott Gasch
   4
   5 """A class to represent a rate of change."""
   6
   7 from typing import Optional
   8
   9
  10 class Rate(object):
  11     """A class to represent a rate of change."""
  12
  13     def __init__(
  14         self,
  15         multiplier: Optional[float] = None,
  16         *,
  17         percentage: Optional[float] = None,
  18         percent_change: Optional[float] = None,
  19     ):
  20         count = 0
  21         if multiplier is not None:
  22             if isinstance(multiplier, str):
  23                 multiplier = multiplier.replace('%', '')
  24                 m = float(multiplier)
  25                 m /= 100
  26                 self.multiplier: float = m
  27             else:
  28                 self.multiplier = multiplier
  29             count += 1
  30         if percentage is not None:
  31             self.multiplier = percentage / 100
  32             count += 1
  33         if percent_change is not None:
  34             self.multiplier = 1.0 + percent_change / 100
  35             count += 1
  36         if count != 1:
  37             raise Exception(
  38                 'Exactly one of percentage, percent_change or multiplier is required.'
  39             )
  40
  41     def apply_to(self, other):
  42         return self.__mul__(other)
  43
  44     def of(self, other):
  45         return self.__mul__(other)
  46
  47     def __float__(self):
  48         return self.multiplier
  49
  50     def __mul__(self, other):
  51         return self.multiplier * float(other)
  52
  53     __rmul__ = __mul__
  54
  55     def __truediv__(self, other):
  56         return self.multiplier / float(other)
  57
  58     def __add__(self, other):
  59         return self.multiplier + float(other)
  60
  61     __radd__ = __add__
  62
  63     def __sub__(self, other):
  64         return self.multiplier - float(other)
  65
  66     def __eq__(self, other):
  67         return self.multiplier == float(other)
  68
  69     def __ne__(self, other):
  70         return not self.__eq__(other)
  71
  72     def __lt__(self, other):
  73         return self.multiplier < float(other)
  74
  75     def __gt__(self, other):
  76         return self.multiplier > float(other)
  77
  78     def __le__(self, other):
  79         return self < other or self == other
  80
  81     def __ge__(self, other):
  82         return self > other or self == other
  83
  84     def __hash__(self):
  85         return self.multiplier
  86
  87     def __repr__(self, *, relative=False, places=3):
  88         if relative:
  89             percentage = (self.multiplier - 1.0) * 100.0
  90         else:
  91             percentage = self.multiplier * 100.0
  92         return f'{percentage:+.{places}f}%'