From 54c50687ddfcd79814aa1f854056b51eacd4e9e1 Mon Sep 17 00:00:00 2001
From: ahmedibrhm <81244897+ahmedibrhm@users.noreply.github.com>
Date: Fri, 8 Jul 2022 00:29:21 -0700
Subject: [PATCH 01/36] DOC #45443 edited the documentation of where/mask
 functions

---
 pandas/core/generic.py | 20 +++++++++++++++++++-
 1 file changed, 19 insertions(+), 1 deletion(-)

diff --git a/pandas/core/generic.py b/pandas/core/generic.py
index ba3474a2513fb..b46eff137394c 100644
--- a/pandas/core/generic.py
+++ b/pandas/core/generic.py
@@ -9614,7 +9614,8 @@ def where(
         The {name} method is an application of the if-then idiom. For each
         element in the calling DataFrame, if ``cond`` is ``{cond}`` the
         element is used; otherwise the corresponding element from the DataFrame
-        ``other`` is used.
+        ``other`` is used. If `cond` {klass} is less in size than `other`, the default bool
+        for the missing value is {cond_rev}.
 
         The signature for :func:`DataFrame.where` differs from
         :func:`numpy.where`. Roughly ``df1.where(m, df2)`` is equivalent to
@@ -9641,6 +9642,23 @@ def where(
         4    NaN
         dtype: float64
 
+        >>> s = pd.Series(range(5))
+        >>> t = pd.Series([True, False])
+        >>> s.where(t,99)
+        0     0
+        1    99
+        2    99
+        3    99
+        4    99
+        dtype: int64
+        >>> s.mask(t, 99)
+        0    99
+        1     1
+        2    99
+        3    99
+        4    99
+        dtype: int64
+
         >>> s.where(s > 1, 10)
         0    10
         1    10

From 2951fb14ef8c589f50b5a28e76878de410968b79 Mon Sep 17 00:00:00 2001
From: ahmedibrhm <81244897+ahmedibrhm@users.noreply.github.com>
Date: Fri, 8 Jul 2022 00:39:29 -0700
Subject: [PATCH 02/36] DOC #45443 edited the documentation of where/mask
 functions

---
 pandas/core/generic.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/pandas/core/generic.py b/pandas/core/generic.py
index b46eff137394c..489ad1e3bf5c2 100644
--- a/pandas/core/generic.py
+++ b/pandas/core/generic.py
@@ -9614,8 +9614,8 @@ def where(
         The {name} method is an application of the if-then idiom. For each
         element in the calling DataFrame, if ``cond`` is ``{cond}`` the
         element is used; otherwise the corresponding element from the DataFrame
-        ``other`` is used. If `cond` {klass} is less in size than `other`, the default bool
-        for the missing value is {cond_rev}.
+        ``other`` is used. If `cond` {klass} is less in size than `other`, the
+        default bool for the missing value is {cond_rev}.
 
         The signature for :func:`DataFrame.where` differs from
         :func:`numpy.where`. Roughly ``df1.where(m, df2)`` is equivalent to

From 8afd6a1fad45a45326e0fdac46eb5cfd8ffac551 Mon Sep 17 00:00:00 2001
From: Ahmed Ibrahim <81244897+ahmedibrhm@users.noreply.github.com>
Date: Fri, 8 Jul 2022 08:12:01 -0700
Subject: [PATCH 03/36] Update generic.py

---
 pandas/core/generic.py | 20 +-------------------
 1 file changed, 1 insertion(+), 19 deletions(-)

diff --git a/pandas/core/generic.py b/pandas/core/generic.py
index 489ad1e3bf5c2..ba3474a2513fb 100644
--- a/pandas/core/generic.py
+++ b/pandas/core/generic.py
@@ -9614,8 +9614,7 @@ def where(
         The {name} method is an application of the if-then idiom. For each
         element in the calling DataFrame, if ``cond`` is ``{cond}`` the
         element is used; otherwise the corresponding element from the DataFrame
-        ``other`` is used. If `cond` {klass} is less in size than `other`, the
-        default bool for the missing value is {cond_rev}.
+        ``other`` is used.
 
         The signature for :func:`DataFrame.where` differs from
         :func:`numpy.where`. Roughly ``df1.where(m, df2)`` is equivalent to
@@ -9642,23 +9641,6 @@ def where(
         4    NaN
         dtype: float64
 
-        >>> s = pd.Series(range(5))
-        >>> t = pd.Series([True, False])
-        >>> s.where(t,99)
-        0     0
-        1    99
-        2    99
-        3    99
-        4    99
-        dtype: int64
-        >>> s.mask(t, 99)
-        0    99
-        1     1
-        2    99
-        3    99
-        4    99
-        dtype: int64
-
         >>> s.where(s > 1, 10)
         0    10
         1    10

From 4d43e69b61d0ec6df931a69a50e70c1494624bbc Mon Sep 17 00:00:00 2001
From: ahmedibrhm <81244897+ahmedibrhm@users.noreply.github.com>
Date: Mon, 11 Jul 2022 12:13:56 -0700
Subject: [PATCH 04/36] Bug 43767 fix

---
 pandas/core/resample.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/pandas/core/resample.py b/pandas/core/resample.py
index 7306d13e44982..fcda7311663cf 100644
--- a/pandas/core/resample.py
+++ b/pandas/core/resample.py
@@ -512,10 +512,10 @@ def _wrap_result(self, result):
         """
         Potentially wrap any results.
         """
-        if isinstance(result, ABCSeries) and self._selection is not None:
+        if (isinstance(result, ABCSeries) or isinstance(result, ABCDataFrame)) and self._selection is not None:
             result.name = self._selection
 
-        if isinstance(result, ABCSeries) and result.empty:
+        if (isinstance(result, ABCSeries) or isinstance(result, ABCDataFrame)) and result.empty:
             obj = self.obj
             # When index is all NaT, result is empty but index is not
             result.index = _asfreq_compat(obj.index[:0], freq=self.freq)

From 75fdb7381496d907e9789ff302a21eb5a6c6ea42 Mon Sep 17 00:00:00 2001
From: ahmedibrhm <81244897+ahmedibrhm@users.noreply.github.com>
Date: Mon, 11 Jul 2022 12:17:43 -0700
Subject: [PATCH 05/36] fixing lines doc

---
 pandas/core/resample.py | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/pandas/core/resample.py b/pandas/core/resample.py
index fcda7311663cf..e857091fb5496 100644
--- a/pandas/core/resample.py
+++ b/pandas/core/resample.py
@@ -512,10 +512,12 @@ def _wrap_result(self, result):
         """
         Potentially wrap any results.
         """
-        if (isinstance(result, ABCSeries) or isinstance(result, ABCDataFrame)) and self._selection is not None:
+        if (isinstance(result, ABCSeries) or 
+        isinstance(result, ABCDataFrame)) and self._selection is not None:
             result.name = self._selection
 
-        if (isinstance(result, ABCSeries) or isinstance(result, ABCDataFrame)) and result.empty:
+        if (isinstance(result, ABCSeries) or
+        isinstance(result, ABCDataFrame)) and result.empty:
             obj = self.obj
             # When index is all NaT, result is empty but index is not
             result.index = _asfreq_compat(obj.index[:0], freq=self.freq)

From 26dc5e82dbc1dbd0b67a3a0b2ad7fd172927a24c Mon Sep 17 00:00:00 2001
From: ahmedibrhm <81244897+ahmedibrhm@users.noreply.github.com>
Date: Mon, 11 Jul 2022 12:19:37 -0700
Subject: [PATCH 06/36] visual indent

---
 pandas/core/resample.py | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/pandas/core/resample.py b/pandas/core/resample.py
index e857091fb5496..886d97d4d191a 100644
--- a/pandas/core/resample.py
+++ b/pandas/core/resample.py
@@ -512,12 +512,12 @@ def _wrap_result(self, result):
         """
         Potentially wrap any results.
         """
-        if (isinstance(result, ABCSeries) or 
-        isinstance(result, ABCDataFrame)) and self._selection is not None:
+        if (isinstance(result, ABCSeries) or
+            isinstance(result, ABCDataFrame)) and self._selection is not None:
             result.name = self._selection
 
         if (isinstance(result, ABCSeries) or
-        isinstance(result, ABCDataFrame)) and result.empty:
+            isinstance(result, ABCDataFrame)) and result.empty:
             obj = self.obj
             # When index is all NaT, result is empty but index is not
             result.index = _asfreq_compat(obj.index[:0], freq=self.freq)

From 47bcbb307df70be0dd0341c859ff71f10a0ca92b Mon Sep 17 00:00:00 2001
From: ahmedibrhm <81244897+ahmedibrhm@users.noreply.github.com>
Date: Mon, 11 Jul 2022 12:20:32 -0700
Subject: [PATCH 07/36] visual indent

---
 pandas/core/resample.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/pandas/core/resample.py b/pandas/core/resample.py
index 886d97d4d191a..d1dc4cbce6d74 100644
--- a/pandas/core/resample.py
+++ b/pandas/core/resample.py
@@ -513,11 +513,11 @@ def _wrap_result(self, result):
         Potentially wrap any results.
         """
         if (isinstance(result, ABCSeries) or
-            isinstance(result, ABCDataFrame)) and self._selection is not None:
+                isinstance(result, ABCDataFrame)) and self._selection is not None:
             result.name = self._selection
 
         if (isinstance(result, ABCSeries) or
-            isinstance(result, ABCDataFrame)) and result.empty:
+                isinstance(result, ABCDataFrame)) and result.empty:
             obj = self.obj
             # When index is all NaT, result is empty but index is not
             result.index = _asfreq_compat(obj.index[:0], freq=self.freq)

From 390ff5a3ffe3f4a65c3cc019d4a19886fd903543 Mon Sep 17 00:00:00 2001
From: ahmedibrhm <81244897+ahmedibrhm@users.noreply.github.com>
Date: Mon, 11 Jul 2022 12:32:15 -0700
Subject: [PATCH 08/36] indentation

---
 pandas/core/resample.py | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/pandas/core/resample.py b/pandas/core/resample.py
index d1dc4cbce6d74..6041ef896e859 100644
--- a/pandas/core/resample.py
+++ b/pandas/core/resample.py
@@ -512,12 +512,14 @@ def _wrap_result(self, result):
         """
         Potentially wrap any results.
         """
-        if (isinstance(result, ABCSeries) or
-                isinstance(result, ABCDataFrame)) and self._selection is not None:
+        if (
+            isinstance(result, ABCSeries) or isinstance(result, ABCDataFrame)
+        ) and self._selection is not None:
             result.name = self._selection
 
-        if (isinstance(result, ABCSeries) or
-                isinstance(result, ABCDataFrame)) and result.empty:
+        if (
+            isinstance(result, ABCSeries) or isinstance(result, ABCDataFrame)
+        ) and result.empty:
             obj = self.obj
             # When index is all NaT, result is empty but index is not
             result.index = _asfreq_compat(obj.index[:0], freq=self.freq)

From e8e51c4f1b6fdf5d8deb316f4fa00e7cf17f9e9a Mon Sep 17 00:00:00 2001
From: ahmedibrhm <81244897+ahmedibrhm@users.noreply.github.com>
Date: Wed, 13 Jul 2022 10:50:43 -0700
Subject: [PATCH 09/36] grouby.resample bug

---
 pandas/tests/resample/test_resampler_grouper.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pandas/tests/resample/test_resampler_grouper.py b/pandas/tests/resample/test_resampler_grouper.py
index c54d9de009940..2080a59f72062 100644
--- a/pandas/tests/resample/test_resampler_grouper.py
+++ b/pandas/tests/resample/test_resampler_grouper.py
@@ -435,7 +435,7 @@ def test_empty(keys):
     # GH 26411
     df = DataFrame([], columns=["a", "b"], index=TimedeltaIndex([]))
     result = df.groupby(keys).resample(rule=pd.to_timedelta("00:00:01")).mean()
-    expected = DataFrame(columns=["a", "b"]).set_index(keys, drop=False)
+    expected = DataFrame(columns=["a", "b"]).set_index(keys.append(np.NaN), drop=False)
     if len(keys) == 1:
         expected.index.name = keys[0]
 

From d05f473b3968cea0c62fefa8404d2a47a0f972c6 Mon Sep 17 00:00:00 2001
From: ahmedibrhm <81244897+ahmedibrhm@users.noreply.github.com>
Date: Wed, 13 Jul 2022 11:51:31 -0700
Subject: [PATCH 10/36] groubby.sample

---
 pandas/core/resample.py                         | 2 +-
 pandas/tests/resample/test_resampler_grouper.py | 8 ++++++--
 2 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/pandas/core/resample.py b/pandas/core/resample.py
index ec7d6925db72e..58e99166f1180 100644
--- a/pandas/core/resample.py
+++ b/pandas/core/resample.py
@@ -522,7 +522,7 @@ def _wrap_result(self, result):
         ) and result.empty:
             obj = self.obj
             # When index is all NaT, result is empty but index is not
-            result.index = _asfreq_compat(obj.index[:0], freq=self.freq)
+            result.set_index(_asfreq_compat(obj.index[:0], freq=self.freq), inplace=True, append=True)
             result.name = getattr(obj, "name", None)
 
         return result
diff --git a/pandas/tests/resample/test_resampler_grouper.py b/pandas/tests/resample/test_resampler_grouper.py
index b122667b70374..7c1b28783e754 100644
--- a/pandas/tests/resample/test_resampler_grouper.py
+++ b/pandas/tests/resample/test_resampler_grouper.py
@@ -433,9 +433,13 @@ def test_resample_groupby_agg_listlike():
 @pytest.mark.parametrize("keys", [["a"], ["a", "b"]])
 def test_empty(keys):
     # GH 26411
-    df = DataFrame([], columns=["a", "b"], index=TimedeltaIndex([]))
+    df = DataFrame([], columns=["a", "b", "date"])
+    df["date"] = pd.to_datetime(df["date"])
+    df.set_index("date", inplace=True)
     result = df.groupby(keys).resample(rule=pd.to_timedelta("00:00:01")).mean()
-    expected = DataFrame(columns=["a", "b"]).set_index(keys.append(np.NaN), drop=False)
+    expected = DataFrame(columns=["a", "b", "date"]).set_index(keys, drop=False)
+    expected["date"] = pd.to_datetime(expected["date"])
+    expected.set_index("date", append=True, drop =True, inplace = True)
     if len(keys) == 1:
         expected.index.name = keys[0]
 

From 9c1fc4fd42f041bcf54523a1799cd9f47190532b Mon Sep 17 00:00:00 2001
From: ahmedibrhm <81244897+ahmedibrhm@users.noreply.github.com>
Date: Wed, 13 Jul 2022 12:01:31 -0700
Subject: [PATCH 11/36] syntax

---
 pandas/core/resample.py                         | 5 ++++-
 pandas/tests/resample/test_resampler_grouper.py | 2 +-
 2 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/pandas/core/resample.py b/pandas/core/resample.py
index 58e99166f1180..eed69b8c3f013 100644
--- a/pandas/core/resample.py
+++ b/pandas/core/resample.py
@@ -522,7 +522,10 @@ def _wrap_result(self, result):
         ) and result.empty:
             obj = self.obj
             # When index is all NaT, result is empty but index is not
-            result.set_index(_asfreq_compat(obj.index[:0], freq=self.freq), inplace=True, append=True)
+            result.set_index (
+                               _asfreq_compat(obj.index[:0], freq=self.freq),
+                               inplace=True, append=True
+            )
             result.name = getattr(obj, "name", None)
 
         return result
diff --git a/pandas/tests/resample/test_resampler_grouper.py b/pandas/tests/resample/test_resampler_grouper.py
index 7c1b28783e754..800cad7eb191b 100644
--- a/pandas/tests/resample/test_resampler_grouper.py
+++ b/pandas/tests/resample/test_resampler_grouper.py
@@ -439,7 +439,7 @@ def test_empty(keys):
     result = df.groupby(keys).resample(rule=pd.to_timedelta("00:00:01")).mean()
     expected = DataFrame(columns=["a", "b", "date"]).set_index(keys, drop=False)
     expected["date"] = pd.to_datetime(expected["date"])
-    expected.set_index("date", append=True, drop =True, inplace = True)
+    expected.set_index("date", append=True, drop=True, inplace=True)
     if len(keys) == 1:
         expected.index.name = keys[0]
 

From c6717645c66f1c7c84651555291e33a649eaac83 Mon Sep 17 00:00:00 2001
From: ahmedibrhm <81244897+ahmedibrhm@users.noreply.github.com>
Date: Wed, 13 Jul 2022 12:02:57 -0700
Subject: [PATCH 12/36] syntax

---
 pandas/core/resample.py | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/pandas/core/resample.py b/pandas/core/resample.py
index eed69b8c3f013..8c1e31af9d6e2 100644
--- a/pandas/core/resample.py
+++ b/pandas/core/resample.py
@@ -522,9 +522,8 @@ def _wrap_result(self, result):
         ) and result.empty:
             obj = self.obj
             # When index is all NaT, result is empty but index is not
-            result.set_index (
-                               _asfreq_compat(obj.index[:0], freq=self.freq),
-                               inplace=True, append=True
+            result.set_index(
+                _asfreq_compat(obj.index[:0], freq=self.freq), inplace=True, append=True
             )
             result.name = getattr(obj, "name", None)
 

From cdb642bca8738d468d5de2f3104a0b9ab3cfac7e Mon Sep 17 00:00:00 2001
From: ahmedibrhm <81244897+ahmedibrhm@users.noreply.github.com>
Date: Wed, 13 Jul 2022 12:03:50 -0700
Subject: [PATCH 13/36] syntax

---
 pandas/core/resample.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pandas/core/resample.py b/pandas/core/resample.py
index 8c1e31af9d6e2..755332e1b8d90 100644
--- a/pandas/core/resample.py
+++ b/pandas/core/resample.py
@@ -522,7 +522,7 @@ def _wrap_result(self, result):
         ) and result.empty:
             obj = self.obj
             # When index is all NaT, result is empty but index is not
-            result.set_index(
+            result.set_index (
                 _asfreq_compat(obj.index[:0], freq=self.freq), inplace=True, append=True
             )
             result.name = getattr(obj, "name", None)

From 891bc7c8bf66b9928f6c28333077274e2169a91b Mon Sep 17 00:00:00 2001
From: ahmedibrhm <81244897+ahmedibrhm@users.noreply.github.com>
Date: Wed, 13 Jul 2022 12:04:57 -0700
Subject: [PATCH 14/36] syntax

---
 pandas/core/resample.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pandas/core/resample.py b/pandas/core/resample.py
index 755332e1b8d90..8c1e31af9d6e2 100644
--- a/pandas/core/resample.py
+++ b/pandas/core/resample.py
@@ -522,7 +522,7 @@ def _wrap_result(self, result):
         ) and result.empty:
             obj = self.obj
             # When index is all NaT, result is empty but index is not
-            result.set_index (
+            result.set_index(
                 _asfreq_compat(obj.index[:0], freq=self.freq), inplace=True, append=True
             )
             result.name = getattr(obj, "name", None)

From 34dcf226ecb6cdaf6a697c2bb2a9530124c2668e Mon Sep 17 00:00:00 2001
From: ahmedibrhm <81244897+ahmedibrhm@users.noreply.github.com>
Date: Wed, 13 Jul 2022 12:11:34 -0700
Subject: [PATCH 15/36] what's new

---
 doc/source/whatsnew/v1.5.0.rst | 1 +
 1 file changed, 1 insertion(+)

diff --git a/doc/source/whatsnew/v1.5.0.rst b/doc/source/whatsnew/v1.5.0.rst
index a6408b940119d..d442fc95ff9fc 100644
--- a/doc/source/whatsnew/v1.5.0.rst
+++ b/doc/source/whatsnew/v1.5.0.rst
@@ -1001,6 +1001,7 @@ Groupby/resample/rolling
 - Bug in :meth:`DataFrame.resample` reduction methods when used with ``on`` would attempt to aggregate the provided column (:issue:`47079`)
 - Bug in :meth:`DataFrame.groupby` and :meth:`Series.groupby` would not respect ``dropna=False`` when the input DataFrame/Series had a NaN values in a :class:`MultiIndex` (:issue:`46783`)
 - Bug in :meth:`DataFrameGroupBy.resample` raises ``KeyError`` when getting the result from a key list which misses the resample key (:issue:`47362`)
+- Bug in :meth:`DataFrameGroupBy.resample` produces inconsistent results when passing empty DataFrame (:issue:`47705`)
 -
 
 Reshaping

From 2a51ddf67889b5e14a4c3733c71a23e155efc7bf Mon Sep 17 00:00:00 2001
From: ahmedibrhm <81244897+ahmedibrhm@users.noreply.github.com>
Date: Wed, 13 Jul 2022 12:21:29 -0700
Subject: [PATCH 16/36] flake8 error

---
 pandas/tests/resample/test_resampler_grouper.py | 1 -
 1 file changed, 1 deletion(-)

diff --git a/pandas/tests/resample/test_resampler_grouper.py b/pandas/tests/resample/test_resampler_grouper.py
index 800cad7eb191b..7598b82e750b1 100644
--- a/pandas/tests/resample/test_resampler_grouper.py
+++ b/pandas/tests/resample/test_resampler_grouper.py
@@ -11,7 +11,6 @@
     DataFrame,
     Index,
     Series,
-    TimedeltaIndex,
     Timestamp,
 )
 import pandas._testing as tm

From 1fe7026c177de77ac2f11e710f241e29a83942b3 Mon Sep 17 00:00:00 2001
From: ahmedibrhm <81244897+ahmedibrhm@users.noreply.github.com>
Date: Wed, 13 Jul 2022 14:11:20 -0700
Subject: [PATCH 17/36] pytest

---
 pandas/core/resample.py | 18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/pandas/core/resample.py b/pandas/core/resample.py
index 8c1e31af9d6e2..9339a822f34aa 100644
--- a/pandas/core/resample.py
+++ b/pandas/core/resample.py
@@ -512,19 +512,19 @@ def _wrap_result(self, result):
         """
         Potentially wrap any results.
         """
-        if (
-            isinstance(result, ABCSeries) or isinstance(result, ABCDataFrame)
-        ) and self._selection is not None:
-            result.name = self._selection
-
-        if (
-            isinstance(result, ABCSeries) or isinstance(result, ABCDataFrame)
-        ) and result.empty:
+        if isinstance(result, ABCDataFrame) and result.empty:
             obj = self.obj
-            # When index is all NaT, result is empty but index is not
             result.set_index(
                 _asfreq_compat(obj.index[:0], freq=self.freq), inplace=True, append=True
             )
+            
+        if isinstance(result, ABCSeries) and self._selection is not None:
+            result.name = self._selection
+
+        if isinstance(result, ABCSeries) and result.empty:
+            obj = self.obj
+            # When index is all NaT, result is empty but index is not
+            result.index = _asfreq_compat(obj.index[:0], freq=self.freq)
             result.name = getattr(obj, "name", None)
 
         return result

From 9d48bfc5ea0b00ef97c4cc59b5a681ba1e35bc62 Mon Sep 17 00:00:00 2001
From: ahmedibrhm <81244897+ahmedibrhm@users.noreply.github.com>
Date: Wed, 13 Jul 2022 14:12:31 -0700
Subject: [PATCH 18/36] blank line

---
 pandas/core/resample.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pandas/core/resample.py b/pandas/core/resample.py
index 9339a822f34aa..415631d021692 100644
--- a/pandas/core/resample.py
+++ b/pandas/core/resample.py
@@ -517,7 +517,7 @@ def _wrap_result(self, result):
             result.set_index(
                 _asfreq_compat(obj.index[:0], freq=self.freq), inplace=True, append=True
             )
-            
+
         if isinstance(result, ABCSeries) and self._selection is not None:
             result.name = self._selection
 

From a076f443403a0078d3d315dbd1076a6598a3e1c9 Mon Sep 17 00:00:00 2001
From: ahmedibrhm <81244897+ahmedibrhm@users.noreply.github.com>
Date: Fri, 15 Jul 2022 16:02:02 -0700
Subject: [PATCH 19/36] editting resample

---
 pandas/core/resample.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pandas/core/resample.py b/pandas/core/resample.py
index 415631d021692..12c17956b4a27 100644
--- a/pandas/core/resample.py
+++ b/pandas/core/resample.py
@@ -512,7 +512,7 @@ def _wrap_result(self, result):
         """
         Potentially wrap any results.
         """
-        if isinstance(result, ABCDataFrame) and result.empty:
+        if isinstance(result, ABCDataFrame) and result.empty and len(result.index) != 0:
             obj = self.obj
             result.set_index(
                 _asfreq_compat(obj.index[:0], freq=self.freq), inplace=True, append=True

From 1450abd104a380007d2bd5fc9c832e46d56c83ba Mon Sep 17 00:00:00 2001
From: ahmedibrhm <81244897+ahmedibrhm@users.noreply.github.com>
Date: Fri, 15 Jul 2022 19:31:18 -0700
Subject: [PATCH 20/36] editting resample

---
 pandas/core/resample.py                         | 2 +-
 pandas/tests/resample/test_resampler_grouper.py | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/pandas/core/resample.py b/pandas/core/resample.py
index 12c17956b4a27..d493ac94b894e 100644
--- a/pandas/core/resample.py
+++ b/pandas/core/resample.py
@@ -512,7 +512,7 @@ def _wrap_result(self, result):
         """
         Potentially wrap any results.
         """
-        if isinstance(result, ABCDataFrame) and result.empty and len(result.index) != 0:
+        if isinstance(result, ABCDataFrame) and result.empty and type(result.index) != PeriodIndex:
             obj = self.obj
             result.set_index(
                 _asfreq_compat(obj.index[:0], freq=self.freq), inplace=True, append=True
diff --git a/pandas/tests/resample/test_resampler_grouper.py b/pandas/tests/resample/test_resampler_grouper.py
index 7598b82e750b1..1a3305a1d1930 100644
--- a/pandas/tests/resample/test_resampler_grouper.py
+++ b/pandas/tests/resample/test_resampler_grouper.py
@@ -430,7 +430,7 @@ def test_resample_groupby_agg_listlike():
 
 
 @pytest.mark.parametrize("keys", [["a"], ["a", "b"]])
-def test_empty(keys):
+def test_resample_empty_Dataframe(keys):
     # GH 26411
     df = DataFrame([], columns=["a", "b", "date"])
     df["date"] = pd.to_datetime(df["date"])

From 0a45b1fb0ed686e7a415643d510e3194f5645abb Mon Sep 17 00:00:00 2001
From: ahmedibrhm <81244897+ahmedibrhm@users.noreply.github.com>
Date: Fri, 15 Jul 2022 19:32:38 -0700
Subject: [PATCH 21/36] syntax

---
 pandas/core/resample.py | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/pandas/core/resample.py b/pandas/core/resample.py
index d493ac94b894e..45e6db0e9a480 100644
--- a/pandas/core/resample.py
+++ b/pandas/core/resample.py
@@ -512,7 +512,8 @@ def _wrap_result(self, result):
         """
         Potentially wrap any results.
         """
-        if isinstance(result, ABCDataFrame) and result.empty and type(result.index) != PeriodIndex:
+        if isinstance(result, ABCDataFrame) and
+        result.empty and type(result.index) != PeriodIndex:
             obj = self.obj
             result.set_index(
                 _asfreq_compat(obj.index[:0], freq=self.freq), inplace=True, append=True

From c04db0e5f0f6ecb15502ee387c4dd7112be3f6b3 Mon Sep 17 00:00:00 2001
From: ahmedibrhm <81244897+ahmedibrhm@users.noreply.github.com>
Date: Fri, 15 Jul 2022 19:34:25 -0700
Subject: [PATCH 22/36] syntax

---
 pandas/core/resample.py | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/pandas/core/resample.py b/pandas/core/resample.py
index 45e6db0e9a480..96294241b42da 100644
--- a/pandas/core/resample.py
+++ b/pandas/core/resample.py
@@ -512,8 +512,10 @@ def _wrap_result(self, result):
         """
         Potentially wrap any results.
         """
-        if isinstance(result, ABCDataFrame) and
-        result.empty and type(result.index) != PeriodIndex:
+        if (
+            isinstance(result, ABCDataFrame) and
+                result.empty and type(result.index) != PeriodIndex
+        ):
             obj = self.obj
             result.set_index(
                 _asfreq_compat(obj.index[:0], freq=self.freq), inplace=True, append=True

From 3a9070d3e2f0eed58d665eb5f4a44fcfe15551e0 Mon Sep 17 00:00:00 2001
From: ahmedibrhm <81244897+ahmedibrhm@users.noreply.github.com>
Date: Fri, 15 Jul 2022 20:27:59 -0700
Subject: [PATCH 23/36] syntax

---
 pandas/core/resample.py | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/pandas/core/resample.py b/pandas/core/resample.py
index 96294241b42da..75b4e5a8baf36 100644
--- a/pandas/core/resample.py
+++ b/pandas/core/resample.py
@@ -512,9 +512,10 @@ def _wrap_result(self, result):
         """
         Potentially wrap any results.
         """
-        if (
-            isinstance(result, ABCDataFrame) and
-                result.empty and type(result.index) != PeriodIndex
+        if(
+            isinstance(result, ABCDataFrame)
+            and result.empty
+            and type(result.index) != PeriodIndex
         ):
             obj = self.obj
             result.set_index(

From e683177e6adb7566bbe88204d70983d84f2504b5 Mon Sep 17 00:00:00 2001
From: ahmedibrhm <81244897+ahmedibrhm@users.noreply.github.com>
Date: Fri, 15 Jul 2022 20:31:55 -0700
Subject: [PATCH 24/36] space

---
 pandas/core/resample.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pandas/core/resample.py b/pandas/core/resample.py
index 75b4e5a8baf36..6cd8ecef1fb73 100644
--- a/pandas/core/resample.py
+++ b/pandas/core/resample.py
@@ -512,7 +512,7 @@ def _wrap_result(self, result):
         """
         Potentially wrap any results.
         """
-        if(
+        if (
             isinstance(result, ABCDataFrame)
             and result.empty
             and type(result.index) != PeriodIndex

From b10a311cbd967c723be261d0696a8dfa51685770 Mon Sep 17 00:00:00 2001
From: ahmedibrhm <81244897+ahmedibrhm@users.noreply.github.com>
Date: Fri, 15 Jul 2022 21:09:59 -0700
Subject: [PATCH 25/36] space

---
 pandas/core/resample.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/pandas/core/resample.py b/pandas/core/resample.py
index 6cd8ecef1fb73..d7661476686e0 100644
--- a/pandas/core/resample.py
+++ b/pandas/core/resample.py
@@ -512,12 +512,13 @@ def _wrap_result(self, result):
         """
         Potentially wrap any results.
         """
+        obj = self.obj
+
         if (
             isinstance(result, ABCDataFrame)
             and result.empty
             and type(result.index) != PeriodIndex
         ):
-            obj = self.obj
             result.set_index(
                 _asfreq_compat(obj.index[:0], freq=self.freq), inplace=True, append=True
             )
@@ -526,7 +527,6 @@ def _wrap_result(self, result):
             result.name = self._selection
 
         if isinstance(result, ABCSeries) and result.empty:
-            obj = self.obj
             # When index is all NaT, result is empty but index is not
             result.index = _asfreq_compat(obj.index[:0], freq=self.freq)
             result.name = getattr(obj, "name", None)

From d3af97b88246fe1c34f1f2c42dafcefb7899ee6c Mon Sep 17 00:00:00 2001
From: ahmedibrhm <81244897+ahmedibrhm@users.noreply.github.com>
Date: Fri, 15 Jul 2022 21:11:14 -0700
Subject: [PATCH 26/36] space

---
 pandas/core/resample.py | 1 -
 1 file changed, 1 deletion(-)

diff --git a/pandas/core/resample.py b/pandas/core/resample.py
index d7661476686e0..ab3895e89b5ca 100644
--- a/pandas/core/resample.py
+++ b/pandas/core/resample.py
@@ -513,7 +513,6 @@ def _wrap_result(self, result):
         Potentially wrap any results.
         """
         obj = self.obj
-
         if (
             isinstance(result, ABCDataFrame)
             and result.empty

From 23d37cefc2f2d5598ff14eee7b5e878547d6e093 Mon Sep 17 00:00:00 2001
From: ahmedibrhm <81244897+ahmedibrhm@users.noreply.github.com>
Date: Mon, 18 Jul 2022 12:44:29 -0700
Subject: [PATCH 27/36] inplace

---
 pandas/core/resample.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/pandas/core/resample.py b/pandas/core/resample.py
index ab3895e89b5ca..6e008ef37a06d 100644
--- a/pandas/core/resample.py
+++ b/pandas/core/resample.py
@@ -518,8 +518,8 @@ def _wrap_result(self, result):
             and result.empty
             and type(result.index) != PeriodIndex
         ):
-            result.set_index(
-                _asfreq_compat(obj.index[:0], freq=self.freq), inplace=True, append=True
+            resule = result.set_index(
+                _asfreq_compat(obj.index[:0], freq=self.freq), append=True
             )
 
         if isinstance(result, ABCSeries) and self._selection is not None:

From 42f141b9280370b900e1d78289a95e978d57d911 Mon Sep 17 00:00:00 2001
From: ahmedibrhm <81244897+ahmedibrhm@users.noreply.github.com>
Date: Mon, 18 Jul 2022 12:47:25 -0700
Subject: [PATCH 28/36] spelling

---
 pandas/core/resample.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pandas/core/resample.py b/pandas/core/resample.py
index 6e008ef37a06d..637936242239d 100644
--- a/pandas/core/resample.py
+++ b/pandas/core/resample.py
@@ -518,7 +518,7 @@ def _wrap_result(self, result):
             and result.empty
             and type(result.index) != PeriodIndex
         ):
-            resule = result.set_index(
+            result = result.set_index(
                 _asfreq_compat(obj.index[:0], freq=self.freq), append=True
             )
 

From b54483bfe57f2aa1fc93c51015758f5fe7d84391 Mon Sep 17 00:00:00 2001
From: ahmedibrhm <81244897+ahmedibrhm@users.noreply.github.com>
Date: Mon, 18 Jul 2022 12:50:14 -0700
Subject: [PATCH 29/36] test

---
 pandas/tests/resample/test_resampler_grouper.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/pandas/tests/resample/test_resampler_grouper.py b/pandas/tests/resample/test_resampler_grouper.py
index 1a3305a1d1930..5ba2d34e4606c 100644
--- a/pandas/tests/resample/test_resampler_grouper.py
+++ b/pandas/tests/resample/test_resampler_grouper.py
@@ -434,11 +434,11 @@ def test_resample_empty_Dataframe(keys):
     # GH 26411
     df = DataFrame([], columns=["a", "b", "date"])
     df["date"] = pd.to_datetime(df["date"])
-    df.set_index("date", inplace=True)
+    df = df.set_index("date")
     result = df.groupby(keys).resample(rule=pd.to_timedelta("00:00:01")).mean()
     expected = DataFrame(columns=["a", "b", "date"]).set_index(keys, drop=False)
     expected["date"] = pd.to_datetime(expected["date"])
-    expected.set_index("date", append=True, drop=True, inplace=True)
+    expected = expected.set_index("date", append=True, drop=True)
     if len(keys) == 1:
         expected.index.name = keys[0]
 

From 5e12d91a90193c48fe7aa7b9e6699f5780f0b252 Mon Sep 17 00:00:00 2001
From: ahmedibrhm <81244897+ahmedibrhm@users.noreply.github.com>
Date: Wed, 10 Aug 2022 20:43:50 -0700
Subject: [PATCH 30/36] test resampler

---
 .../tests/resample/test_resampler_grouper.py  | 27 ++++++++++++++-----
 1 file changed, 20 insertions(+), 7 deletions(-)

diff --git a/pandas/tests/resample/test_resampler_grouper.py b/pandas/tests/resample/test_resampler_grouper.py
index 5ba2d34e4606c..06de59953da9e 100644
--- a/pandas/tests/resample/test_resampler_grouper.py
+++ b/pandas/tests/resample/test_resampler_grouper.py
@@ -11,6 +11,7 @@
     DataFrame,
     Index,
     Series,
+    TimedeltaIndex,
     Timestamp,
 )
 import pandas._testing as tm
@@ -430,15 +431,11 @@ def test_resample_groupby_agg_listlike():
 
 
 @pytest.mark.parametrize("keys", [["a"], ["a", "b"]])
-def test_resample_empty_Dataframe(keys):
+def test_empty(keys):
     # GH 26411
-    df = DataFrame([], columns=["a", "b", "date"])
-    df["date"] = pd.to_datetime(df["date"])
-    df = df.set_index("date")
+    df = DataFrame([], columns=["a", "b"], index=TimedeltaIndex([]))
     result = df.groupby(keys).resample(rule=pd.to_timedelta("00:00:01")).mean()
-    expected = DataFrame(columns=["a", "b", "date"]).set_index(keys, drop=False)
-    expected["date"] = pd.to_datetime(expected["date"])
-    expected = expected.set_index("date", append=True, drop=True)
+    expected = DataFrame(columns=["a", "b"]).set_index(keys, drop=False)
     if len(keys) == 1:
         expected.index.name = keys[0]
 
@@ -500,3 +497,19 @@ def test_groupby_resample_with_list_of_keys():
         ),
     )
     tm.assert_frame_equal(result, expected)
+
+
+@pytest.mark.parametrize("keys", [["a"], ["a", "b"]])
+def test_resample_empty_Dataframe(keys):
+    # GH 47705
+    df = DataFrame([], columns=["a", "b", "date"])
+    df["date"] = pd.to_datetime(df["date"])
+    df = df.set_index("date")
+    result = df.groupby(keys).resample(rule=pd.to_timedelta("00:00:01")).mean()
+    expected = DataFrame(columns=["a", "b", "date"]).set_index(keys, drop=False)
+    expected["date"] = pd.to_datetime(expected["date"])
+    expected = expected.set_index("date", append=True, drop=True)
+    if len(keys) == 1:
+        expected.index.name = keys[0]
+
+    tm.assert_frame_equal(result, expected)

From 2f462ab9ad6429da7bb7390d4b4697e23a3af5f7 Mon Sep 17 00:00:00 2001
From: ahmedibrhm <81244897+ahmedibrhm@users.noreply.github.com>
Date: Wed, 10 Aug 2022 21:40:00 -0700
Subject: [PATCH 31/36] tests

---
 pandas/tests/resample/test_resampler_grouper.py | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/pandas/tests/resample/test_resampler_grouper.py b/pandas/tests/resample/test_resampler_grouper.py
index 06de59953da9e..084e1d6a66619 100644
--- a/pandas/tests/resample/test_resampler_grouper.py
+++ b/pandas/tests/resample/test_resampler_grouper.py
@@ -435,7 +435,9 @@ def test_empty(keys):
     # GH 26411
     df = DataFrame([], columns=["a", "b"], index=TimedeltaIndex([]))
     result = df.groupby(keys).resample(rule=pd.to_timedelta("00:00:01")).mean()
-    expected = DataFrame(columns=["a", "b"]).set_index(keys, drop=False)
+    expected = DataFrame(columns=["a", "b"]).set_index(keys, drop=False).set_index(
+        TimedeltaIndex([]), append=True
+    )
     if len(keys) == 1:
         expected.index.name = keys[0]
 

From 727a1c74570c723d1932f4f5bb9f8b2de11b14b7 Mon Sep 17 00:00:00 2001
From: ahmedibrhm <81244897+ahmedibrhm@users.noreply.github.com>
Date: Sat, 13 Aug 2022 10:56:46 -0700
Subject: [PATCH 32/36] tests

---
 pandas/core/resample.py                         | 2 +-
 pandas/tests/resample/test_resampler_grouper.py | 6 ++++--
 2 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/pandas/core/resample.py b/pandas/core/resample.py
index 08ee68f0c1451..a58b89afce852 100644
--- a/pandas/core/resample.py
+++ b/pandas/core/resample.py
@@ -517,7 +517,7 @@ def _wrap_result(self, result):
         if (
             isinstance(result, ABCDataFrame)
             and result.empty
-            and type(result.index) != PeriodIndex
+            and not isinstance(result.index, PeriodIndex)
         ):
             result = result.set_index(
                 _asfreq_compat(obj.index[:0], freq=self.freq), append=True
diff --git a/pandas/tests/resample/test_resampler_grouper.py b/pandas/tests/resample/test_resampler_grouper.py
index 084e1d6a66619..904b0e69c9a7d 100644
--- a/pandas/tests/resample/test_resampler_grouper.py
+++ b/pandas/tests/resample/test_resampler_grouper.py
@@ -435,8 +435,10 @@ def test_empty(keys):
     # GH 26411
     df = DataFrame([], columns=["a", "b"], index=TimedeltaIndex([]))
     result = df.groupby(keys).resample(rule=pd.to_timedelta("00:00:01")).mean()
-    expected = DataFrame(columns=["a", "b"]).set_index(keys, drop=False).set_index(
-        TimedeltaIndex([]), append=True
+    expected = (
+        DataFrame(columns=["a", "b"])
+        .set_index(keys, drop=False)
+        .set_index(TimedeltaIndex([]), append=True)
     )
     if len(keys) == 1:
         expected.index.name = keys[0]

From 0b01594a07d4b20b267753180205db0077a209cd Mon Sep 17 00:00:00 2001
From: Ahmed Ibrahim <81244897+ahmedibrhm@users.noreply.github.com>
Date: Mon, 15 Aug 2022 10:23:59 -0700
Subject: [PATCH 33/36] Update resample.py

---
 pandas/core/resample.py | 1 +
 1 file changed, 1 insertion(+)

diff --git a/pandas/core/resample.py b/pandas/core/resample.py
index c8ee33db7ea20..aea08790da9d4 100644
--- a/pandas/core/resample.py
+++ b/pandas/core/resample.py
@@ -514,6 +514,7 @@ def _wrap_result(self, result):
         """
         Potentially wrap any results.
         """
+        # GH 47705
         obj = self.obj
         if (
             isinstance(result, ABCDataFrame)

From 25e7cfd11f4dd74532cff8c77080189571908766 Mon Sep 17 00:00:00 2001
From: Ahmed Ibrahim <81244897+ahmedibrhm@users.noreply.github.com>
Date: Mon, 15 Aug 2022 10:39:43 -0700
Subject: [PATCH 34/36] Update resample.py

---
 pandas/core/resample.py | 1 +
 1 file changed, 1 insertion(+)

diff --git a/pandas/core/resample.py b/pandas/core/resample.py
index aea08790da9d4..02543bc1dca5c 100644
--- a/pandas/core/resample.py
+++ b/pandas/core/resample.py
@@ -515,6 +515,7 @@ def _wrap_result(self, result):
         Potentially wrap any results.
         """
         # GH 47705
+
         obj = self.obj
         if (
             isinstance(result, ABCDataFrame)

From 900933b492c837fd862af963d6955cce93121116 Mon Sep 17 00:00:00 2001
From: Ahmed Ibrahim <81244897+ahmedibrhm@users.noreply.github.com>
Date: Mon, 15 Aug 2022 10:40:12 -0700
Subject: [PATCH 35/36] Update resample.py

---
 pandas/core/resample.py | 1 -
 1 file changed, 1 deletion(-)

diff --git a/pandas/core/resample.py b/pandas/core/resample.py
index 02543bc1dca5c..aea08790da9d4 100644
--- a/pandas/core/resample.py
+++ b/pandas/core/resample.py
@@ -515,7 +515,6 @@ def _wrap_result(self, result):
         Potentially wrap any results.
         """
         # GH 47705
-
         obj = self.obj
         if (
             isinstance(result, ABCDataFrame)

From c178d4dd6112b3263b8567b6c4f6f913f4ea800e Mon Sep 17 00:00:00 2001
From: Ahmed Ibrahim <81244897+ahmedibrhm@users.noreply.github.com>
Date: Fri, 30 Sep 2022 22:59:41 +0800
Subject: [PATCH 36/36] Update v1.6.0.rst

---
 doc/source/whatsnew/v1.6.0.rst | 1 +
 1 file changed, 1 insertion(+)

diff --git a/doc/source/whatsnew/v1.6.0.rst b/doc/source/whatsnew/v1.6.0.rst
index d726f69286469..a83f8a01343ab 100644
--- a/doc/source/whatsnew/v1.6.0.rst
+++ b/doc/source/whatsnew/v1.6.0.rst
@@ -238,6 +238,7 @@ Plotting
 Groupby/resample/rolling
 ^^^^^^^^^^^^^^^^^^^^^^^^
 - Bug in :meth:`DataFrameGroupBy.sample` raises ``ValueError`` when the object is empty (:issue:`48459`)
+- Bug in :meth:`DataFrameGroupBy.resample` produces inconsistent results when passing empty DataFrame (:issue:`47705`)
 -
 
 Reshaping