From a5f5954fe540eb9ffcf8378b287008aa9bf08237 Mon Sep 17 00:00:00 2001
From: MarcoGorelli <33491632+MarcoGorelli@users.noreply.github.com>
Date: Sat, 26 Aug 2023 14:15:04 +0200
Subject: [PATCH 1/2] add dataframe.join

---
 .../dataframe_api/dataframe_object.py         | 42 +++++++++++++++++++
 1 file changed, 42 insertions(+)

diff --git a/spec/API_specification/dataframe_api/dataframe_object.py b/spec/API_specification/dataframe_api/dataframe_object.py
index cd109a7e..c7d4826a 100644
--- a/spec/API_specification/dataframe_api/dataframe_object.py
+++ b/spec/API_specification/dataframe_api/dataframe_object.py
@@ -897,3 +897,45 @@ def to_array_object(self, dtype: Any) -> Any:
         understanding that consuming libraries would then use the
         ``array-api-compat`` package to convert it to a Standard-compliant array.
         """
+    
+    def join(
+        self,
+        other: DataFrame,
+        *,
+        how: Literal['left', 'inner', 'outer'],
+        on: str | list[str] | None = None,
+        left_on: str | list[str] | None = None,
+        right_on: str | list[str] | None = None,
+    ) -> DataFrame:
+        """
+        Join with other dataframe.
+
+        Parameters
+        ----------
+        other : DataFrame
+            Dataframe to join with.
+        how : str
+            Kind of join to perform.
+            Must be one of {'left', 'inner', 'outer'}.
+        on : str | list[str], optional
+            Key(s) to use to perform join.
+            Cannot be used in conjunction with `left_on` or `right_on`.
+        left_on : str | list[str], optional
+            Key(s) from `self` to perform `join` on.
+            If more than one key is given, it must be
+            the same length as `right_on`.
+            Cannot be used in conjunction with `on`.
+        right_on : str | list[str], optional
+            Key(s) from `other` to perform `join` on.
+            If more than one key is given, it must be
+            the same length as `left_on`.
+            Cannot be used in conjunction with `on`.
+        
+        Returns
+        -------
+        DataFrame
+
+        Notes
+        -----
+        Either `on`, or both `left_on` and `right_on`, must be specified.
+        """

From 2978c33eac21afef3cf8ab0e6bb06f8775fd2298 Mon Sep 17 00:00:00 2001
From: MarcoGorelli <33491632+MarcoGorelli@users.noreply.github.com>
Date: Mon, 28 Aug 2023 14:24:10 +0200
Subject: [PATCH 2/2] remove on

---
 .../dataframe_api/dataframe_object.py          | 18 ++++--------------
 1 file changed, 4 insertions(+), 14 deletions(-)

diff --git a/spec/API_specification/dataframe_api/dataframe_object.py b/spec/API_specification/dataframe_api/dataframe_object.py
index c7d4826a..f1881328 100644
--- a/spec/API_specification/dataframe_api/dataframe_object.py
+++ b/spec/API_specification/dataframe_api/dataframe_object.py
@@ -903,9 +903,8 @@ def join(
         other: DataFrame,
         *,
         how: Literal['left', 'inner', 'outer'],
-        on: str | list[str] | None = None,
-        left_on: str | list[str] | None = None,
-        right_on: str | list[str] | None = None,
+        left_on: str | list[str],
+        right_on: str | list[str],
     ) -> DataFrame:
         """
         Join with other dataframe.
@@ -917,25 +916,16 @@ def join(
         how : str
             Kind of join to perform.
             Must be one of {'left', 'inner', 'outer'}.
-        on : str | list[str], optional
-            Key(s) to use to perform join.
-            Cannot be used in conjunction with `left_on` or `right_on`.
-        left_on : str | list[str], optional
+        left_on : str | list[str]
             Key(s) from `self` to perform `join` on.
             If more than one key is given, it must be
             the same length as `right_on`.
-            Cannot be used in conjunction with `on`.
-        right_on : str | list[str], optional
+        right_on : str | list[str]
             Key(s) from `other` to perform `join` on.
             If more than one key is given, it must be
             the same length as `left_on`.
-            Cannot be used in conjunction with `on`.
         
         Returns
         -------
         DataFrame
-
-        Notes
-        -----
-        Either `on`, or both `left_on` and `right_on`, must be specified.
         """