simplify: prefer sum over len + if

astral-sh/ruff#13050

src/pymatgen/analysis/functional_groups.py

@@ -169,7 +169,7 @@ def get_special_carbon(self, elements=None):
 
             neighbor_spec = [str(self.species[n]) for n in neighbors]
 
-            ons = len([n for n in neighbor_spec if n in ["O", "N", "S"]])
+            ons = sum(n in ["O", "N", "S"] for n in neighbor_spec)
 
             if len(neighbors) == 4 and ons >= 2:
                 specials.add(node)

src/pymatgen/analysis/magnetism/heisenberg.py

@@ -770,8 +770,8 @@ def _do_screen(structures, energies):
             screened_structures (list): Sorted structures.
             screened_energies (list): Sorted energies.
         """
-        magmoms = [s.site_properties["magmom"] for s in structures]
-        n_below_1ub = [len([m for m in ms if abs(m) < 1]) for ms in magmoms]
+        magmoms = [struct.site_properties["magmom"] for struct in structures]
+        n_below_1ub = [sum(abs(m) < 1 for m in ms) for ms in magmoms]
 
         df = pd.DataFrame(
             {

src/pymatgen/core/lattice.py

@@ -1744,7 +1744,7 @@ def get_integer_index(
     mi += 0  # converts -0 to 0
 
     def n_minus(index):
-        return len([h for h in index if h < 0])
+        return sum(h < 0 for h in index)
 
     if n_minus(mi) > n_minus(mi * -1):
         mi *= -1

src/pymatgen/core/surface.py

@@ -2114,7 +2114,7 @@ def math_lcm(a: int, b: int) -> int:
     transf_hkl = np.array([idx // divisor for idx in transf_hkl])
 
     # Get positive Miller index
-    if len([i for i in transf_hkl if i < 0]) > 1:
+    if sum(idx < 0 for idx in transf_hkl) > 1:
         transf_hkl *= -1
 
     return tuple(transf_hkl)

src/pymatgen/electronic_structure/cohp.py

@@ -193,7 +193,7 @@ def has_antibnd_states_below_efermi(
             limit (float): Only COHP higher than this value will be considered.
         """
         populations = self.cohp
-        n_energies_below_efermi = len([energy for energy in self.energies if energy <= self.efermi])
+        n_energies_below_efermi = sum(energy <= self.efermi for energy in self.energies)
 
         if populations is None:
             return None

src/pymatgen/entries/mixing_scheme.py

@@ -238,8 +238,8 @@ def process_entries(
                 processed_entry_list.append(entry)
 
         if verbose:
-            count_type_1 = len([e for e in processed_entry_list if e.parameters["run_type"] in self.valid_rtypes_1])
-            count_type_2 = len([e for e in processed_entry_list if e.parameters["run_type"] in self.valid_rtypes_2])
+            count_type_1 = sum(entry.parameters["run_type"] in self.valid_rtypes_1 for entry in processed_entry_list)
+            count_type_2 = sum(entry.parameters["run_type"] in self.valid_rtypes_2 for entry in processed_entry_list)
             print(
                 f"\nProcessing complete. Mixed entries contain {count_type_1} {self.run_type_1} and {count_type_2} "
                 f"{self.run_type_2} entries.\n"

tests/analysis/test_adsorption.py

@@ -87,7 +87,7 @@ def test_generate_adsorption_structures(self):
         assert len(structures) == 4
         sites = self.asf_111.find_adsorption_sites()
         # Check repeat functionality
-        assert len([site for site in structures[0] if site.properties["surface_properties"] != "adsorbate"]) == 4 * len(
+        assert len(site.properties["surface_properties"] != "adsorbate" for site in structures[0]) == 4 * len(
             self.asf_111.slab
         )
         for n, structure in enumerate(structures):