ENH: maybe_convert_objects seen NaT speed-up (#27300)

Author: BeforeFlight

asv_bench/benchmarks/algorithms.py

@@ -2,6 +2,8 @@
 
 import numpy as np
 
+from pandas._libs import lib
+
 import pandas as pd
 from pandas.util import testing as tm
 
@@ -13,6 +15,19 @@
         pass
 
 
+class MaybeConvertObjects:
+    def setup(self):
+        N = 10 ** 5
+
+        data = list(range(N))
+        data[0] = pd.NaT
+        data = np.array(data)
+        self.data = data
+
+    def time_maybe_convert_objects(self):
+        lib.maybe_convert_objects(self.data)
+
+
 class Factorize:
 
     params = [[True, False], ["int", "uint", "float", "string"]]

doc/source/whatsnew/v0.25.0.rst

@@ -940,7 +940,6 @@ Performance improvements
 - For :meth:`to_datetime` changed default value of cache parameter to ``True`` (:issue:`26043`)
 - Improved performance of :class:`DatetimeIndex` and :class:`PeriodIndex` slicing given non-unique, monotonic data (:issue:`27136`).
 
-
 .. _whatsnew_0250.bug_fixes:
 
 Bug fixes

pandas/_libs/lib.pyx

@@ -1955,6 +1955,7 @@ def maybe_convert_objects(ndarray[object] objects, bint try_float=0,
                 seen.timedelta_ = 1
             if not (convert_datetime or convert_timedelta):
                 seen.object_ = 1
+                break
         elif util.is_bool_object(val):
             seen.bool_ = 1
             bools[i] = val