DeltaFloat

deltafloat.py

# coding: utf-8

class DeltaFloat(float):
    def __new__(cls, value, delta=0.0001):
        self = float.__new__(cls, value)
        self.delta = delta
        return self
    
    def __eq__(self, other):
        x = float(self)
        delta = self.delta
        if x - delta <= float(other) <= x + delta:
            return True
        return False
    
    def __lt__(self, other):
        return float(self) + self.delta < float(other)
    
    def __le__(self, other):
        return float(self) - self.delta <= float(other)
    
    def __gt__(self, other):
        return float(self) - self.delta > float(other)
    
    def __ge__(self, other):
        return float(self) + self.delta >= float(other)

gistfile1.txt

A naive float derived class that have an implicit "delta" for comparisons - 
this can overcome rounding errors in simple operations while keeping the code
easy to read.

Note that operations with numbers of this class will yield "normal" floats - 
those should be "cast" back to DeltaFloat to keep their features.
Note: this is not designed for transparent/heavy-duty math work:
a proper implementation implementing all methods in numbers.Real would be needed for that.

```
>>> a = DeltaFloat(4.31, delta=0.01)
>>> a == 4.32
False
>>> a == 4.315
True

```