Refactored _round

Author: cbertinato

pandas/_libs/tslibs/timestamps.pyx

@@ -602,27 +602,24 @@ class Timestamp(_Timestamp):
         else:
             value = self.value
 
-        # GH 19206
-        # to deal with round-off when unit is large
-        if unit >= 1e9:
-            divisor = 10 ** int(np.log10(unit / 1e7))
-        else:
-            divisor = 1
-
-        if unit < 1000 and unit % 1000 != 0:
+        if unit < 1000:
             # for nano rounding, work with the last 6 digits separately
             # due to float precision
             r = (buff * (value // buff) + unit *
                  (rounder((value % buff) * (1 / float(unit)))).astype('i8'))
-        elif unit >= 1000 and unit % 1000 != 0:
-            msg = 'Precision will be lost using frequency: {}'
-            warnings.warn(msg.format(freq))
-            r = (unit *
-                 rounder((value * divisor / float(unit)) / divisor)
-                 .astype('i8'))
         else:
-            r = (unit *
-                 rounder((value * divisor / float(unit)) / divisor)
+            if unit % 1000 != 0:
+                msg = 'Precision will be lost using frequency: {}'
+                warnings.warn(msg.format(freq))
+
+            # GH19206
+            # to deal with round-off when unit is large
+            if unit >= 1e9:
+                divisor = 10 ** int(np.log10(unit / 1e7))
+            else:
+                divisor = 1
+
+            r = (unit * rounder((value * divisor / float(unit)) / divisor)
                  .astype('i8'))
 
         result = Timestamp(r, unit='ns')