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Added "plain" property to quantity #248

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Merged
merged 4 commits into from
Dec 3, 2024
Merged

Added "plain" property to quantity #248

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f803620
Added "plain" property to quantity
wagenadl Nov 16, 2024
633cf9e
Renamed the “plain” property
wagenadl Nov 19, 2024
856db64
Added test coverage for dimensionless_magnitude
wagenadl Nov 20, 2024
966deea
Added to test coverage for dimensionless_magnitude
wagenadl Nov 20, 2024
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27 changes: 27 additions & 0 deletions quantities/quantity.py
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Original file line number Diff line number Diff line change
Expand Up @@ -145,6 +145,16 @@ def _reference(self):

@property
def magnitude(self):
"""
Returns a view onto the numerical value of the quantity, stripping
away the associated units. For example:
```
import quantities as pq
t = 2 * pq.millisecond
n = t.magnitude # n will be 2 (not 0.002)
```
See also: dimensionless_magnitude.
"""
return self.view(type=np.ndarray)

@property
Expand Down Expand Up @@ -250,6 +260,23 @@ def rescale_preferred(self):
raise Exception("Preferred units for '%s' (or equivalent) not specified in "
"quantites.quantity.PREFERRED." % self.dimensionality)

@property
def dimensionless_magnitude(self):
"""
Returns the numerical value of a dimensionless quantity in the form of
a numpy array. Any decimal prefixes are normalized away first.
For example:
```
import quantities as pq
t = 2 * pq.ms
f = 3 * pq.MHz
n = (t*f).dimensionless_magnitude # n will be 6000 (not 6)
```
If the quantity is not dimensionless, a conversion error is raised.
See also: magnitude.
"""
return self.rescale(unit_registry['dimensionless']).magnitude

@with_doc(np.ndarray.astype)
def astype(self, dtype=None, **kwargs):
'''Scalars are returned as scalar Quantity arrays.'''
Expand Down
7 changes: 7 additions & 0 deletions quantities/tests/test_methods.py
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Expand Up @@ -356,3 +356,10 @@ def test_rescale_integer_argument(self):
Quantity(10, pq.deg).rescale(pq.rad),
np.pi/18*pq.rad
)

def test_dimensionless_magnitude(self):
self.assertEqual((pq.kg/pq.g).dimensionless_magnitude, 1000)
self.assertQuantityEqual((self.q / pq.cm).dimensionless_magnitude,
100 * self.q.magnitude)
self.assertRaises(ValueError, lambda x: x.dimensionless_magnitude,
self.q)
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