Merge remote-tracking branch 'upstream/master' into fu1+sort

Author: TomAugspurger

doc/source/whatsnew/v0.23.0.txt

@@ -843,6 +843,7 @@ Categorical
   ``self`` but in a different order (:issue:`19551`)
 - Bug in :meth:`Index.astype` with a categorical dtype where the resultant index is not converted to a :class:`CategoricalIndex` for all types of index (:issue:`18630`)
 - Bug in :meth:`Series.astype` and ``Categorical.astype()`` where an existing categorical data does not get updated (:issue:`10696`, :issue:`18593`)
+- Bug in :meth:`Series.str.split` with ``expand=True`` incorrectly raising an IndexError on empty strings (:issue:`20002`).
 - Bug in :class:`Index` constructor with ``dtype=CategoricalDtype(...)`` where ``categories`` and ``ordered`` are not maintained (issue:`19032`)
 - Bug in :class:`Series` constructor with scalar and ``dtype=CategoricalDtype(...)`` where ``categories`` and ``ordered`` are not maintained (issue:`19565`)
 - Bug in ``Categorical.__iter__`` not converting to Python types (:issue:`19909`)

pandas/_libs/tslibs/period.pyx

@@ -1355,7 +1355,7 @@ cdef class _Period(object):
 
         Returns
         -------
-        int 
+        int
 
         See Also
         --------
@@ -1371,7 +1371,7 @@ cdef class _Period(object):
         >>> p = pd.Period("2018-02-01", "D")
         >>> p.week
         5
-        
+
         >>> p = pd.Period("2018-01-06", "D")
         >>> p.week
         1

pandas/core/dtypes/inference.py

@@ -28,20 +28,37 @@ def is_number(obj):
     """
     Check if the object is a number.
 
+    Returns True when the object is a number, and False if is not.
+
     Parameters
     ----------
-    obj : The object to check.
+    obj : any type
+        The object to check if is a number.
 
     Returns
     -------
     is_number : bool
         Whether `obj` is a number or not.
 
+    See Also
+    --------
+    pandas.api.types.is_integer: checks a subgroup of numbers
+
     Examples
     --------
-    >>> is_number(1)
+    >>> pd.api.types.is_number(1)
+    True
+    >>> pd.api.types.is_number(7.15)
     True
-    >>> is_number("foo")
+
+    Booleans are valid because they are int subclass.
+
+    >>> pd.api.types.is_number(False)
+    True
+
+    >>> pd.api.types.is_number("foo")
+    False
+    >>> pd.api.types.is_number("5")
     False
     """