example-code-2e/iterables/aritprog_v0.py
2014-12-14 01:26:42 -02:00

25 lines
529 B
Python

"""
Arithmetic progression class
>>> ap = ArithmeticProgression(1, .5, 3)
>>> list(ap)
[1.0, 1.5, 2.0, 2.5]
"""
class ArithmeticProgression:
def __init__(self, begin, step, end=None):
self.begin = begin
self.step = step
self.end = end # None -> "infinite" series
def __iter__(self):
result = type(self.begin + self.step)(self.begin)
forever = self.end is None
while forever or result < self.end:
yield result
result += self.step