Merge pull request #56 from bobleesj/lambda

Avoid lambda flake8 error with private function

Author: sbillinge

diffpy/snmf/containers.py

@@ -8,7 +8,7 @@ class ComponentSignal:
     ----------
     grid: 1d array of floats
       The vector containing the grid points of the component.
-
+    iq: 1d array of floats
       The intensity/g(r) values of the component.
     weights: 1d array of floats
       The vector containing the weight of the component signal for each signal.
@@ -36,22 +36,17 @@ def apply_stretch(self, m):
         Returns
         -------
         tuple of 1d arrays
-          The tuple of vectors where one vector is the stretched component, one vector is the 1st derivative
-          of the stretching operation, and one vector is the second derivative of the stretching operation.
+          The tuple of vectors where one vector is the stretched component, one vector is the 1st derivative of the
+          stretching operation, and one vector is the second derivative of the stretching operation.
         """
         normalized_grid = np.arange(len(self.grid))
-        # func = lambda stretching_factor: np.interp(
-        #     normalized_grid / stretching_factor, normalized_grid, self.iq, left=0, right=0
-        # )
-
-        # E731 do not assign a lambda expression, use a def
-        def func(stretching_factor):
-            return np.interp(normalized_grid / stretching_factor, normalized_grid, self.iq, left=0, right=0)
-
-        derivative_func = numdifftools.Derivative(func)
+        interpolate_intensity = lambda stretching_factor: np.interp(  # noqa: E731
+            normalized_grid / stretching_factor, normalized_grid, self.iq, left=0, right=0
+        )
+        derivative_func = numdifftools.Derivative(interpolate_intensity)
         second_derivative_func = numdifftools.Derivative(derivative_func)
 
-        stretched_component = func(self.stretching_factors[m])
+        stretched_component = interpolate_intensity(self.stretching_factors[m])
         stretched_component_gra = derivative_func(self.stretching_factors[m])
         stretched_component_hess = second_derivative_func(self.stretching_factors[m])