DOC: Added mean function as method of Resampler and updated docstring

Author: donghyyun

pandas/core/resample.py

@@ -983,6 +983,30 @@ def asfreq(self, fill_value=None):
         DataFrame.asfreq: Convert TimeSeries to specified frequency.
         """
         return self._upsample("asfreq", fill_value=fill_value)
+    
+    def mean(
+        self,
+        numeric_only: bool | lib.NoDefault = lib.no_default,
+        *args,
+        **kwargs,
+    ):
+        """
+        Compute mean of groups, excluding missing values.
+
+        Parameters
+        ----------
+        numeric_only : bool, default False
+            Include only `float`, `int` or `boolean` data.
+
+            .. versionadded:: 1.5.0
+
+        Returns
+        -------
+        DataFrame or Series
+            Mean of values within each group.
+        """
+        nv.validate_resampler_func("mean", args, kwargs)
+        return self._downsample("mean", numeric_only=numeric_only)
 
     def std(
         self,
@@ -1173,7 +1197,7 @@ def f(  # type: ignore[misc]
 
 for method in ["sum", "prod", "min", "max", "first", "last"]:
     _add_downsample_kernel(method, ("numeric_only", "min_count"))
-for method in ["mean", "median"]:
+for method in ["median"]:
     _add_downsample_kernel(method, ("numeric_only",))
 for method in ["sem"]:
     _add_downsample_kernel(method, ("ddof", "numeric_only"))