def test_none_scalar_array_raises(self):
with self.assertRaises(Exception) as context:
allow_none_scalar(choices)
self.assertEqual(type(context.exception), TypeError)
self.assertEqual(str(context.exception),
'Argument must be an integer, a float, or None')
def test_none_scalar_none(self):
none_scalar_none = allow_none_scalar(none_scalar)
self.assertEqual(none_scalar_none,
'Argument is an integer, a float, or None')
def test_none_scalar_float(self):
none_scalar_float = allow_none_scalar(good_float)
self.assertEqual(none_scalar_float,
'Argument is an integer, a float, or None')
def rounded_value(number, precision=4):
"""
Rounds a number to a certain decimal place, but returns a non-zero result if the number being rounded is non-zero even if it would round to zero at that level of decimal precision; allows None as a possible input
Parameters
----------
number : int or float
Number to round
precision : int, default=4
Maximum number of digits that can appear after the decimal place of the result
Raises
------
TypeError
First argument must be an integer, a float, or None
ValueError
Last argument must be a positive integer
Returns
-------
number : float
Original number rounded to the number of decimal places indicated by the precision input
See Also
--------
:func:`~regressions.statistics.sort.sorted_list`, :func:`~regressions.statistics.summation.sum_value`
Notes
-----
- Number to round: :math:`n`
- Absolute value of number: :math:`a = |n|`
- Maximum number of digits after decimal place of result: :math:`d`
- Check size of number: :math:`c(a,d) = \\lfloor a\\cdot{10^d} \\rfloor`
- Significant digit: :math:`s(a,d) = \\lfloor ( a\\cdot{10^d} - \\lfloor a\\cdot{10^d} \\rfloor )\\cdot{10} \\rfloor`
- If :math:`c(a,d) = 0`:
- Rounding formula (if :math:`n = 0`): :math:`r = 0`
- If :math:`n \\neq 0`:
- Rounding formula (if :math:`a = n`): :math:`r(d) = 10^{-d}`
- Rounding formula (if :math:`a \\neq n`): :math:`r(d) = -10^{-d}`
- If :math:`c(a,d) \\neq 0`:
- If :math:`a = n`:
- Rounding formula (if :math:`s(a,d) \\geq 5`): :math:`r(a,d) = \\frac{\\lceil a\\cdot{10^d} \\rceil}{10^d}`
- Rounding formula (if :math:`s(a,d) < 5`): :math:`r(a,d) = \\frac{\\lfloor a\\cdot{10^d} \\rfloor}{10^d}`
- If :math:`a \\neq n`:
- Rounding formula (if :math:`s(a,d) \\geq 5`): :math:`r(a,d) = -\\frac{\\lceil a\\cdot{10^d} \\rceil}{10^d}`
- Rounding formula (if :math:`s(a,d) < 5`): :math:`r(a,d) = -\\frac{\\lfloor a\\cdot{10^d} \\rfloor}{10^d}`
- |rounding|
Examples
--------
Import `rounded_value` function from `regressions` library
>>> from regressions.statistics.rounding import rounded_value
Round the number 9.2157823956916472 to six decimal places
>>> number_normal = rounded_value(9.2157825956916472, 6)
>>> print(number_normal)
9.215783
Round the number -0.00000003 to six decimal places
>>> number_abnormal = rounded_value(-0.00000003, 6)
>>> print(number_abnormal)
-1e-6
Round the number 11.725371548561 to four decimal places (without providing a value for the precision argument)
>>> round_skip = rounded_value(11.725371548561)
>>> print(round_skip)
11.7254
"""
# Handle input errors
allow_none_scalar(number)
positive_integer(precision)
# Handle None value
if number == None:
return None
# Circumvent rounding to zero with small positive numbers
elif number < 10**(-precision) and number > 0:
return 10**(-precision)
# Circumvent rounding to zero with small negative numbers
elif number > -10**(-precision) and number < 0:
return -10**(-precision)
# Handle general case
else:
return float(round(number, precision))