Python: Range or numpy Arange with end limit include
In short
I wrote a function crange
, which does what you require.
In the example below, orange
does the job of numpy.arange
crange(1, 1.3, 0.1) >>> [1. 1.1 1.2 1.3]
orange(1, 1.3, 0.1) >>> [1. 1.1 1.2]
crange(0.0, 0.6, 0.2) >>> [0. 0.2 0.4 0.6]
orange(0.0, 0.6, 0.2) >>> [0. 0.2 0.4]
Background information
I had your problem a view times as well. I usually quick-fixed it with adding a small value to stop. As mentioned by Kasrâmvd in the comments, the issue is a bit more complex, as floating point rounding errors can occur in numpy.arange (see here and here).
Unexpected behavior can be found in this example:
>>> numpy.arange(1, 1.3, 0.1)
array([1. , 1.1, 1.2, 1.3])
To clear up things a bit for myself, I decided to stop using numpy.arange if not needed specifically. I instead use my self defined function orange
to avoid unexpected behavior. This combines numpy.isclose and numpy.linspace.
Here is the Code
Enough bla bla - here is the code ^^
import numpy as np
def cust_range(*args, rtol=1e-05, atol=1e-08, include=[True, False]):
"""
Combines numpy.arange and numpy.isclose to mimic
open, half-open and closed intervals.
Avoids also floating point rounding errors as with
>>> numpy.arange(1, 1.3, 0.1)
array([1. , 1.1, 1.2, 1.3])
args: [start, ]stop, [step, ]
as in numpy.arange
rtol, atol: floats
floating point tolerance as in numpy.isclose
include: boolean list-like, length 2
if start and end point are included
"""
# process arguments
if len(args) == 1:
start = 0
stop = args[0]
step = 1
elif len(args) == 2:
start, stop = args
step = 1
else:
assert len(args) == 3
start, stop, step = tuple(args)
# determine number of segments
n = (stop-start)/step + 1
# do rounding for n
if np.isclose(n, np.round(n), rtol=rtol, atol=atol):
n = np.round(n)
# correct for start/end is exluded
if not include[0]:
n -= 1
start += step
if not include[1]:
n -= 1
stop -= step
return np.linspace(start, stop, int(n))
def crange(*args, **kwargs):
return cust_range(*args, **kwargs, include=[True, True])
def orange(*args, **kwargs):
return cust_range(*args, **kwargs, include=[True, False])
print('crange(1, 1.3, 0.1) >>>', crange(1, 1.3, 0.1))
print('orange(1, 1.3, 0.1) >>>', orange(1, 1.3, 0.1))
print('crange(0.0, 0.6, 0.2) >>>', crange(0.0, 0.6, 0.2))
print('orange(0.0, 0.6, 0.2) >>>', orange(0.0, 0.6, 0.2))
A simpler approach to get the desired output is to add the step size in the upper limit. For instance,
np.arange(start, end + step, step)
would allow you to include the end point as well. In your case:
np.arange(0.0, 0.6 + 0.2, 0.2)
would result in
array([0. , 0.2, 0.4, 0.6]).