CLN: collect fastpath in Series.__init__ (pandas-dev#49575)

* CLN: collect fastpath in Series.__init__

* small clean

Co-authored-by: Terji Petersen <[email protected]>

Author: 2 people

pandas/core/series.py

@@ -368,8 +368,7 @@ def __init__(
 
         # we are called internally, so short-circuit
         if fastpath:
-
-            # data is an ndarray, index is defined
+            # data is a ndarray, index is defined
             if not isinstance(data, (SingleBlockManager, SingleArrayManager)):
                 manager = get_option("mode.data_manager")
                 if manager == "block":
@@ -378,103 +377,99 @@ def __init__(
                     data = SingleArrayManager.from_array(data, index)
             if copy:
                 data = data.copy()
-            if index is None:
-                index = data.index
-
-        else:
+            # skips validation of the name
+            object.__setattr__(self, "_name", name)
+            NDFrame.__init__(self, data)
+            return
 
-            name = ibase.maybe_extract_name(name, data, type(self))
+        name = ibase.maybe_extract_name(name, data, type(self))
 
-            if index is not None:
-                index = ensure_index(index)
+        if index is not None:
+            index = ensure_index(index)
 
-            if data is None:
-                data = {}
-            if dtype is not None:
-                dtype = self._validate_dtype(dtype)
+        if data is None:
+            data = {}
+        if dtype is not None:
+            dtype = self._validate_dtype(dtype)
 
-            if isinstance(data, MultiIndex):
-                raise NotImplementedError(
-                    "initializing a Series from a MultiIndex is not supported"
-                )
-            if isinstance(data, Index):
-
-                if dtype is not None:
-                    # astype copies
-                    data = data.astype(dtype)
-                else:
-                    # GH#24096 we need to ensure the index remains immutable
-                    data = data._values.copy()
-                copy = False
+        if isinstance(data, MultiIndex):
+            raise NotImplementedError(
+                "initializing a Series from a MultiIndex is not supported"
+            )
+        if isinstance(data, Index):
 
-            elif isinstance(data, np.ndarray):
-                if len(data.dtype):
-                    # GH#13296 we are dealing with a compound dtype, which
-                    #  should be treated as 2D
-                    raise ValueError(
-                        "Cannot construct a Series from an ndarray with "
-                        "compound dtype.  Use DataFrame instead."
-                    )
-            elif isinstance(data, Series):
-                if index is None:
-                    index = data.index
-                else:
-                    data = data.reindex(index, copy=copy)
-                    copy = False
-                data = data._mgr
-            elif is_dict_like(data):
-                data, index = self._init_dict(data, index, dtype)
-                dtype = None
-                copy = False
-            elif isinstance(data, (SingleBlockManager, SingleArrayManager)):
-                if index is None:
-                    index = data.index
-                elif not data.index.equals(index) or copy:
-                    # GH#19275 SingleBlockManager input should only be called
-                    # internally
-                    raise AssertionError(
-                        "Cannot pass both SingleBlockManager "
-                        "`data` argument and a different "
-                        "`index` argument. `copy` must be False."
-                    )
-
-            elif isinstance(data, ExtensionArray):
-                pass
+            if dtype is not None:
+                # astype copies
+                data = data.astype(dtype)
             else:
-                data = com.maybe_iterable_to_list(data)
-                if is_list_like(data) and not len(data) and dtype is None:
-                    # GH 29405: Pre-2.0, this defaulted to float.
-                    dtype = np.dtype(object)
-
+                # GH#24096 we need to ensure the index remains immutable
+                data = data._values.copy()
+            copy = False
+
+        elif isinstance(data, np.ndarray):
+            if len(data.dtype):
+                # GH#13296 we are dealing with a compound dtype, which
+                #  should be treated as 2D
+                raise ValueError(
+                    "Cannot construct a Series from an ndarray with "
+                    "compound dtype.  Use DataFrame instead."
+                )
+        elif isinstance(data, Series):
             if index is None:
-                if not is_list_like(data):
-                    data = [data]
-                index = default_index(len(data))
-            elif is_list_like(data):
-                com.require_length_match(data, index)
-
-            # create/copy the manager
-            if isinstance(data, (SingleBlockManager, SingleArrayManager)):
-                if dtype is not None:
-                    data = data.astype(dtype=dtype, errors="ignore", copy=copy)
-                elif copy:
-                    data = data.copy()
+                index = data.index
             else:
-                data = sanitize_array(data, index, dtype, copy)
+                data = data.reindex(index, copy=copy)
+                copy = False
+            data = data._mgr
+        elif is_dict_like(data):
+            data, index = self._init_dict(data, index, dtype)
+            dtype = None
+            copy = False
+        elif isinstance(data, (SingleBlockManager, SingleArrayManager)):
+            if index is None:
+                index = data.index
+            elif not data.index.equals(index) or copy:
+                # GH#19275 SingleBlockManager input should only be called
+                # internally
+                raise AssertionError(
+                    "Cannot pass both SingleBlockManager "
+                    "`data` argument and a different "
+                    "`index` argument. `copy` must be False."
+                )
 
-                manager = get_option("mode.data_manager")
-                if manager == "block":
-                    data = SingleBlockManager.from_array(data, index)
-                elif manager == "array":
-                    data = SingleArrayManager.from_array(data, index)
+        elif isinstance(data, ExtensionArray):
+            pass
+        else:
+            data = com.maybe_iterable_to_list(data)
+            if is_list_like(data) and not len(data) and dtype is None:
+                # GH 29405: Pre-2.0, this defaulted to float.
+                dtype = np.dtype(object)
+
+        if index is None:
+            if not is_list_like(data):
+                data = [data]
+            index = default_index(len(data))
+        elif is_list_like(data):
+            com.require_length_match(data, index)
+
+        # create/copy the manager
+        if isinstance(data, (SingleBlockManager, SingleArrayManager)):
+            if dtype is not None:
+                data = data.astype(dtype=dtype, errors="ignore", copy=copy)
+            elif copy:
+                data = data.copy()
+        else:
+            data = sanitize_array(data, index, dtype, copy)
+
+            manager = get_option("mode.data_manager")
+            if manager == "block":
+                data = SingleBlockManager.from_array(data, index)
+            elif manager == "array":
+                data = SingleArrayManager.from_array(data, index)
 
         NDFrame.__init__(self, data)
-        if fastpath:
-            # skips validation of the name
-            object.__setattr__(self, "_name", name)
-        else:
-            self.name = name
-            self._set_axis(0, index)
+        self.name = name
+        self._set_axis(0, index)
 
     def _init_dict(
         self, data, index: Index | None = None, dtype: DtypeObj | None = None