Add command for explicitly formatting quantity units

Author: rprospero

sasdata/quantities/quantity.py

@@ -6,6 +6,7 @@
 from numpy._typing import ArrayLike
 
 from sasdata.quantities import units
+from sasdata.quantities.unit_parser import parse_unit
 from sasdata.quantities.numerical_encoding import numerical_decode, numerical_encode
 from sasdata.quantities.units import NamedUnit, Unit
 
@@ -1180,6 +1181,16 @@ def in_si_with_standard_error(self):
         else:
             return self.in_si(), None
 
+    def explicitly_formatted(self, unit_string: str) -> str:
+        """Returns quantity as a string with specific unit formatting
+
+        Performs any necessary unit conversions, but maintains the exact unit
+        formatting provided by the user.  This can be useful if you have a
+        power expressed in horsepower and you want it expressed as "745.7 N m/s" and not as "745.7 W". """
+        unit = parse_unit(unit_string)
+        quantity = self.in_units_of(unit)
+        return f"{quantity} {unit_string}"
+
     def __eq__(self: Self, other: Self) -> bool | np.ndarray:
         return self.value == other.in_units_of(self.units)
 
@@ -1337,6 +1348,7 @@ def __pow__(self: Self, other: int | float):
 
     @staticmethod
     def _array_repr_format(arr: np.ndarray):
+
         """ Format the array """
         order = len(arr.shape)
         reshaped = arr.reshape(-1)

test/quantities/utest_quantities.py

@@ -131,3 +131,11 @@ def test_equality():
     assert Quantity(1.0, units.angstroms) == Quantity(0.1, units.nanometers)
     assert Quantity(1.0, units.angstroms) != Quantity(0.1, units.angstroms)
     assert Quantity(1.0, units.angstroms) == Quantity(1.0e-10, units.meters)
+
+@pytest.mark.quantity
+def test_explicit_format():
+    value = Quantity(1.0, units.electronvolts)
+    assert value.explicitly_formatted("J") == "1.602176634e-19 J"
+    assert value.explicitly_formatted("N m") == "1.602176634e-19 N m"
+    assert value.explicitly_formatted("m N") == "1.602176634e-19 m N"
+    assert value.explicitly_formatted("m kilogram m / hour / year") == "1.8201532008477443e-08 m kilogram m / hour / year"