Implement DataFrame pct_change

python/cudf/cudf/core/dataframe.py

@@ -6329,6 +6329,46 @@ def explode(self, column, ignore_index=False):
 
         return super()._explode(column, ignore_index)
 
+    def pct_change(
+        self, periods=1, fill_method="ffill", limit=None, freq=None
+    ):
+        """
+        Calculates the percent change between sequential elements
+        in the DataFrame.
+
+        Parameters
+        ----------
+        periods : int, default 1
+            Periods to shift for forming percent change.
+        fill_method : str, default 'ffill'
+            How to handle NAs before computing percent changes.
+        limit : int, optional
+            The number of consecutive NAs to fill before stopping.
+            Not yet implemented.
+        freq : str, optional
+            Increment to use from time series API.
+            Not yet implemented.
+
+        Returns
+        -------
+        DataFrame
+        """
+        if limit is not None:
+            raise NotImplementedError("limit parameter not supported yet.")
+        if freq is not None:
+            raise NotImplementedError("freq parameter not supported yet.")
+        elif fill_method not in {"ffill", "pad", "bfill", "backfill"}:
+            raise ValueError(
+                "fill_method must be one of 'ffill', 'pad', "
+                "'bfill', or 'backfill'."
+            )
+
+        data = self.fillna(method=fill_method, limit=limit)
+
+        return data.diff(periods=periods) / data.shift(
+            periods=periods, freq=freq
+        )
+
     def __dataframe__(
         self, nan_as_null: bool = False, allow_copy: bool = True
     ):