from fractions import Fraction
def spread(start, end, count, mode=1):
"""spread(start, end, count [, mode]) -> generator
Yield a sequence of evenly-spaced numbers between start and end.
The range start...end is divided into count evenly-spaced (or as close to
evenly-spaced as possible) intervals. The end-points of each interval are
then yielded, optionally including or excluding start and end themselves.
By default, start is included and end is excluded.
For example, with start=0, end=2.1 and count=3, the range is divided into
three intervals:
(0.0)-----(0.7)-----(1.4)-----(2.1)
resulting in:
>>> list(spread(0.0, 2.1, 3))
[0.0, 0.7, 1.4]
Optional argument mode controls whether spread() includes the start and
end values. mode must be an int. Bit zero of mode controls whether start
is included (on) or excluded (off); bit one does the same for end. Hence:
0 -> open interval (start and end both excluded)
1 -> half-open (start included, end excluded)
2 -> half open (start excluded, end included)
3 -> closed (start and end both included)
By default, mode=1 and only start is included in the output.
(Note: depending on mode, the number of values returned can be count,
count-1 or count+1.)
"""
if not isinstance(mode, int):
raise TypeError('mode must be an int')
if count != int(count):
raise ValueError('count must be an integer')
if count <= 0:
raise ValueError('count must be positive')
if mode & 1:
yield start
width = Fraction(end-start)
start = Fraction(start)
for i in range(1, count):
yield float(start + i*width/count)
if mode & 2:
yield end
