From 10f1bdedb72e5f988eaa4ca974a65906f1bbc3f0 Mon Sep 17 00:00:00 2001
From: Brock <jbrockmendel@gmail.com>
Date: Tue, 16 Feb 2021 14:33:14 -0800
Subject: [PATCH 1/7] PERF: is_list_like

---
 asv_bench/benchmarks/libs.py | 36 ++++++++++++++++++++++++++++++++++++
 pandas/_libs/lib.pyx         |  5 +++--
 2 files changed, 39 insertions(+), 2 deletions(-)
 create mode 100644 asv_bench/benchmarks/libs.py

diff --git a/asv_bench/benchmarks/libs.py b/asv_bench/benchmarks/libs.py
new file mode 100644
index 0000000000000..8c04b89d99526
--- /dev/null
+++ b/asv_bench/benchmarks/libs.py
@@ -0,0 +1,36 @@
+"""
+Benchmarks for code in pandas/_libs, excluding pandas/_libs/tslibs,
+which has its own directory
+"""
+import numpy as np
+
+from pandas._libs.lib import is_list_like, is_scalar
+
+from pandas import NA, NaT
+
+# TODO: share with something in pd._testing?
+scalars = [
+    0,
+    1.0,
+    1 + 2j,
+    True,
+    "foo",
+    b"bar",
+    None,
+    np.datetime64(123),
+    np.timedelta64(123),
+    NaT,
+    NA,
+]
+zero_dims = [np.array("123")]
+listlikes = [np.array([1, 2, 3]), {0: "foo"}, set(1, 2, 3), [1, 2, 3], (1, 2, 3)]
+
+
+class ScalarListLike:
+    params = scalars + zero_dims + listlikes
+
+    def time_is_list_like(self, param):
+        is_list_like(param)
+
+    def time_is_scalar(self, param):
+        is_scalar(param)
diff --git a/pandas/_libs/lib.pyx b/pandas/_libs/lib.pyx
index 3a11e7fbbdf33..be0e777ab7807 100644
--- a/pandas/_libs/lib.pyx
+++ b/pandas/_libs/lib.pyx
@@ -1044,11 +1044,12 @@ def is_list_like(obj: object, allow_sets: bool = True) -> bool:
 
 cdef inline bint c_is_list_like(object obj, bint allow_sets) except -1:
     return (
-        isinstance(obj, abc.Iterable)
+        # equiv: `isinstance(obj, abc.Iterable)`
+        hasattr(obj, "__iter__") and not isinstance(obj, type)
         # we do not count strings/unicode/bytes as list-like
         and not isinstance(obj, (str, bytes))
         # exclude zero-dimensional numpy arrays, effectively scalars
-        and not (util.is_array(obj) and obj.ndim == 0)
+        and not cnp.PyArray_IsZeroDim(obj)
         # exclude sets if allow_sets is False
         and not (allow_sets is False and isinstance(obj, abc.Set))
     )

From b8856bec88369ad369803f1354014b5597253729 Mon Sep 17 00:00:00 2001
From: Brock <jbrockmendel@gmail.com>
Date: Tue, 16 Feb 2021 15:01:43 -0800
Subject: [PATCH 2/7] typo fixup

---
 asv_bench/benchmarks/libs.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/asv_bench/benchmarks/libs.py b/asv_bench/benchmarks/libs.py
index 8c04b89d99526..20feaf4f37312 100644
--- a/asv_bench/benchmarks/libs.py
+++ b/asv_bench/benchmarks/libs.py
@@ -17,8 +17,8 @@
     "foo",
     b"bar",
     None,
-    np.datetime64(123),
-    np.timedelta64(123),
+    np.datetime64(123, "ns"),
+    np.timedelta64(123, "ns"),
     NaT,
     NA,
 ]

From 60e100857a8f5606413baf6d3d1283720c9cbee2 Mon Sep 17 00:00:00 2001
From: Brock <jbrockmendel@gmail.com>
Date: Tue, 16 Feb 2021 15:12:36 -0800
Subject: [PATCH 3/7] isort fixup

---
 asv_bench/benchmarks/libs.py | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/asv_bench/benchmarks/libs.py b/asv_bench/benchmarks/libs.py
index 20feaf4f37312..16f669711dfa5 100644
--- a/asv_bench/benchmarks/libs.py
+++ b/asv_bench/benchmarks/libs.py
@@ -4,9 +4,14 @@
 """
 import numpy as np
 
-from pandas._libs.lib import is_list_like, is_scalar
-
-from pandas import NA, NaT
+from pandas._libs.lib import (
+    is_list_like,
+    is_scalar,
+)
+from pandas import (
+    NA,
+    NaT,
+)
 
 # TODO: share with something in pd._testing?
 scalars = [

From dda658850cf7fdfb5517466643255daabaa32be0 Mon Sep 17 00:00:00 2001
From: Brock <jbrockmendel@gmail.com>
Date: Tue, 16 Feb 2021 15:21:26 -0800
Subject: [PATCH 4/7] isort fixup

---
 asv_bench/benchmarks/libs.py | 1 +
 1 file changed, 1 insertion(+)

diff --git a/asv_bench/benchmarks/libs.py b/asv_bench/benchmarks/libs.py
index 16f669711dfa5..1c8de6d9f8e56 100644
--- a/asv_bench/benchmarks/libs.py
+++ b/asv_bench/benchmarks/libs.py
@@ -8,6 +8,7 @@
     is_list_like,
     is_scalar,
 )
+
 from pandas import (
     NA,
     NaT,

From caddcfe24e9989b1299375a61ac60ab8bcb83632 Mon Sep 17 00:00:00 2001
From: Brock <jbrockmendel@gmail.com>
Date: Tue, 16 Feb 2021 19:32:36 -0800
Subject: [PATCH 5/7] typo fixup

---
 asv_bench/benchmarks/libs.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/asv_bench/benchmarks/libs.py b/asv_bench/benchmarks/libs.py
index 1c8de6d9f8e56..e1dbb6b26a546 100644
--- a/asv_bench/benchmarks/libs.py
+++ b/asv_bench/benchmarks/libs.py
@@ -29,7 +29,7 @@
     NA,
 ]
 zero_dims = [np.array("123")]
-listlikes = [np.array([1, 2, 3]), {0: "foo"}, set(1, 2, 3), [1, 2, 3], (1, 2, 3)]
+listlikes = [np.array([1, 2, 3]), {0: "foo"}, set([1, 2, 3]), [1, 2, 3], (1, 2, 3)]
 
 
 class ScalarListLike:

From c00dc11718ac743c273e4bd3635ba3586504798e Mon Sep 17 00:00:00 2001
From: Brock <jbrockmendel@gmail.com>
Date: Wed, 17 Feb 2021 08:11:08 -0800
Subject: [PATCH 6/7] dummy commit to force hook


From fec9c1b9fe75ee44ce03d10ee20e53d556ad6c57 Mon Sep 17 00:00:00 2001
From: Brock <jbrockmendel@gmail.com>
Date: Wed, 17 Feb 2021 08:13:06 -0800
Subject: [PATCH 7/7] dummy commit to force hook

---
 asv_bench/benchmarks/libs.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/asv_bench/benchmarks/libs.py b/asv_bench/benchmarks/libs.py
index e1dbb6b26a546..f5c2397945cea 100644
--- a/asv_bench/benchmarks/libs.py
+++ b/asv_bench/benchmarks/libs.py
@@ -29,7 +29,7 @@
     NA,
 ]
 zero_dims = [np.array("123")]
-listlikes = [np.array([1, 2, 3]), {0: "foo"}, set([1, 2, 3]), [1, 2, 3], (1, 2, 3)]
+listlikes = [np.array([1, 2, 3]), {0: 1}, {1, 2, 3}, [1, 2, 3], (1, 2, 3)]
 
 
 class ScalarListLike: