Catch exception around much smaller piece of code

Author: jbrockmendel

pandas/core/tools/datetimes.py

@@ -236,40 +236,41 @@ def _convert_listlike_datetimes(arg, box, format, name=None, tz=None,
             require_iso8601 = not infer_datetime_format
             format = None
 
-    try:
-        result = None
+    result = None
+    tz_parsed = None
 
-        if format is not None:
-            # shortcut formatting here
-            if format == '%Y%m%d':
-                try:
-                    result = _attempt_YYYYMMDD(arg, errors=errors)
-                except (ValueError, TypeError, tslibs.OutOfBoundsDatetime):
-                    raise ValueError("cannot convert the input to "
-                                     "'%Y%m%d' date format")
+    if format is not None:
+        # shortcut formatting here
+        if format == '%Y%m%d':
+            try:
+                result = _attempt_YYYYMMDD(arg, errors=errors)
+            except (ValueError, TypeError, tslibs.OutOfBoundsDatetime):
+                raise ValueError("cannot convert the input to "
+                                 "'%Y%m%d' date format")
 
-            # fallback
-            if result is None:
-                try:
-                    result, timezones = array_strptime(
-                        arg, format, exact=exact, errors=errors)
-                    if '%Z' in format or '%z' in format:
-                        return _return_parsed_timezone_results(
-                            result, timezones, box, tz, name)
-                except tslibs.OutOfBoundsDatetime:
+        # fallback
+        if result is None:
+            try:
+                result, timezones = array_strptime(arg, format,
+                                                   exact=exact, errors=errors)
+                if '%Z' in format or '%z' in format:
+                    return _return_parsed_timezone_results(result, timezones,
+                                                           box, tz, name)
+            except tslibs.OutOfBoundsDatetime:
+                if errors == 'raise':
+                    raise
+                result = arg
+            except ValueError:
+                # if format was inferred, try falling back
+                # to array_to_datetime - terminate here
+                # for specified formats
+                if not infer_datetime_format:
                     if errors == 'raise':
                         raise
                     result = arg
-                except ValueError:
-                    # if format was inferred, try falling back
-                    # to array_to_datetime - terminate here
-                    # for specified formats
-                    if not infer_datetime_format:
-                        if errors == 'raise':
-                            raise
-                        result = arg
-
-        if result is None and (format is None or infer_datetime_format):
+
+    if result is None and (format is None or infer_datetime_format):
+        try:
             result, tz_parsed = tslib.array_to_datetime(
                 arg,
                 errors=errors,
@@ -278,35 +279,41 @@ def _convert_listlike_datetimes(arg, box, format, name=None, tz=None,
                 yearfirst=yearfirst,
                 require_iso8601=require_iso8601
             )
-            if tz_parsed is not None:
-                if box:
-                    # We can take a shortcut since the datetime64 numpy array
-                    # is in UTC
-                    return DatetimeIndex._simple_new(result, name=name,
-                                                     tz=tz_parsed)
-                else:
-                    # Convert the datetime64 numpy array to an numpy array
-                    # of datetime objects
-                    result = [Timestamp(ts, tz=tz_parsed).to_pydatetime()
-                              for ts in result]
-                    return np.array(result, dtype=object)
+        except ValueError as e:
+            # reached when array_to_datetime raises "unless utc=True..."
+            try:
+                values, tz = conversion.datetime_to_datetime64(arg)
+                return DatetimeIndex._simple_new(values, name=name, tz=tz)
+            except (ValueError, TypeError):
+                raise e
+
+    return _maybe_box_date_results(result, box, tz, name, tz_parsed=tz_parsed)
+
 
+def _maybe_box_date_results(result, box, tz, name, tz_parsed=None):
+    from pandas import Index, DatetimeIndex
+    if tz_parsed is not None:
         if box:
-            # Ensure we return an Index in all cases where box=True
-            if is_datetime64_dtype(result):
-                return DatetimeIndex(result, tz=tz, name=name)
-            elif is_object_dtype(result):
-                # e.g. an Index of datetime objects
-                from pandas import Index
-                return Index(result, name=name)
-        return result
+            # We can take a shortcut since the datetime64 numpy array
+            # is in UTC
+            return DatetimeIndex._simple_new(result, name=name,
+                                             tz=tz_parsed)
+        else:
+            # Convert the datetime64 numpy array to an numpy array
+            # of datetime objects
+            result = [Timestamp(ts, tz=tz_parsed).to_pydatetime()
+                      for ts in result]
+            return np.array(result, dtype=object)
+
+    elif box:
+        # Ensure we return an Index in all cases where box=True
+        if is_datetime64_dtype(result):
+            return DatetimeIndex(result, tz=tz, name=name)
+        elif is_object_dtype(result):
+            # e.g. an Index of datetime objects
+            return Index(result, name=name)
 
-    except ValueError as e:
-        try:
-            values, tz = conversion.datetime_to_datetime64(arg)
-            return DatetimeIndex._simple_new(values, name=name, tz=tz)
-        except (ValueError, TypeError):
-            raise e
+    return result
 
 
 def _adjust_to_origin(arg, origin, unit):