Resolution docstring (pandas-dev#21122)

Author: chalmerlowe

pandas/_libs/tslibs/timedeltas.pyx

@@ -839,7 +839,46 @@ cdef class _Timedelta(timedelta):
 
     @property
     def resolution(self):
-        """ return a string representing the lowest resolution that we have """
+        """
+        Return a string representing the lowest timedelta resolution.
+
+        Each timedelta has a defined resolution that represents the lowest OR
+        most granular level of precision. Each level of resolution is
+        represented by a short string as defined below:
+
+        Resolution:     Return value
+
+        * Days:         'D'
+        * Hours:        'H'
+        * Minutes:      'T'
+        * Seconds:      'S'
+        * Milliseconds: 'L'
+        * Microseconds: 'U'
+        * Nanoseconds:  'N'
+
+        Returns
+        -------
+        str
+            Timedelta resolution.
+
+        Examples
+        --------
+        >>> td = pd.Timedelta('1 days 2 min 3 us 42 ns')
+        >>> td.resolution
+        'N'
+
+        >>> td = pd.Timedelta('1 days 2 min 3 us')
+        >>> td.resolution
+        'U'
+
+        >>> td = pd.Timedelta('2 min 3 s')
+        >>> td.resolution
+        'S'
+
+        >>> td = pd.Timedelta(36, unit='us')
+        >>> td.resolution
+        'U'
+        """
 
         self._ensure_components()
         if self._ns: