perf: use list join instead of string concatenation in loop

Author: akshatsinha0

samtranslator/translator/translator.py

@@ -98,9 +98,15 @@ def _get_function_names(
                     )
                     if not resolved_function_name:
                         continue
-                    self.function_names.setdefault(api_name, "")
-                    self.function_names[api_name] += str(resolved_function_name)
-        return self.function_names
+                    # OLD APPROACH: String concatenation in loop
+                    # self.function_names.setdefault(api_name, "")
+                    # self.function_names[api_name] += str(resolved_function_name)
+                    # NEW APPROACH: Collect in list
+                    if api_name not in self.function_names:
+                        self.function_names[api_name]=[]
+                    self.function_names[api_name].append(str(resolved_function_name))
+        #backward compatibility
+        return {api: "".join(names) for api, names in self.function_names.items()}
 
     def translate(  # noqa: PLR0912, PLR0915
         self,
@@ -127,7 +133,9 @@ def translate(  # noqa: PLR0912, PLR0915
         self.feature_toggle = feature_toggle or FeatureToggle(
             FeatureToggleDefaultConfigProvider(), stage=None, account_id=None, region=None
         )
-        self.function_names: Dict[Any, Any] = {}
+        # OLD: self.function_names: Dict[Any, Any] = {}
+        # NEW: Use List[str] for efficient accumulation, convert to str when needed
+        self.function_names: Dict[str, List[str]] = {}
         self.redeploy_restapi_parameters = {}
         sam_parameter_values = SamParameterValues(parameter_values)
         sam_parameter_values.add_default_parameter_values(sam_template)