DOC: Fix examples in pandas/core/strings.py (#33328)

Author: ShaharNaveh

ci/code_checks.sh

@@ -296,6 +296,10 @@ if [[ -z "$CHECK" || "$CHECK" == "doctests" ]]; then
     pytest -q --doctest-modules pandas/core/series.py
     RET=$(($RET + $?)) ; echo $MSG "DONE"
 
+    MSG='Doctests strings.py' ; echo $MSG
+    pytest -q --doctest-modules pandas/core/strings.py
+    RET=$(($RET + $?)) ; echo $MSG "DONE"
+
     # Directories
 
     MSG='Doctests arrays'; echo $MSG

pandas/core/strings.py

@@ -652,9 +652,9 @@ def str_replace(arr, pat, repl, n=-1, case=None, flags=0, regex=True):
     To get the idea:
 
     >>> pd.Series(['foo', 'fuz', np.nan]).str.replace('f', repr)
-    0    <_sre.SRE_Match object; span=(0, 1), match='f'>oo
-    1    <_sre.SRE_Match object; span=(0, 1), match='f'>uz
-    2                                                  NaN
+    0    <re.Match object; span=(0, 1), match='f'>oo
+    1    <re.Match object; span=(0, 1), match='f'>uz
+    2                                            NaN
     dtype: object
 
     Reverse every lowercase alphabetic word:
@@ -2076,8 +2076,18 @@ class StringMethods(NoNewAttributesMixin):
 
     Examples
     --------
-    >>> s.str.split('_')
-    >>> s.str.replace('_', '')
+    >>> s = pd.Series(["A_Str_Series"])
+    >>> s
+    0    A_Str_Series
+    dtype: object
+
+    >>> s.str.split("_")
+    0    [A, Str, Series]
+    dtype: object
+
+    >>> s.str.replace("_", "")
+    0    AStrSeries
+    dtype: object
     """
 
     def __init__(self, data):
@@ -2583,9 +2593,14 @@ def cat(self, others=None, sep=None, na_rep=None, join="left"):
 
     Examples
     --------
-    >>> s = pd.Series(["this is a regular sentence",
-    ...                "https://docs.python.org/3/tutorial/index.html",
-    ...                np.nan])
+    >>> s = pd.Series(
+    ...     [
+    ...         "this is a regular sentence",
+    ...         "https://docs.python.org/3/tutorial/index.html",
+    ...         np.nan
+    ...     ]
+    ... )
+    >>> s
     0                       this is a regular sentence
     1    https://docs.python.org/3/tutorial/index.html
     2                                              NaN
@@ -2625,7 +2640,7 @@ def cat(self, others=None, sep=None, na_rep=None, join="left"):
 
     The `pat` parameter can be used to split by other characters.
 
-    >>> s.str.split(pat = "/")
+    >>> s.str.split(pat="/")
     0                         [this is a regular sentence]
     1    [https:, , docs.python.org, 3, tutorial, index...
     2                                                  NaN
@@ -2636,14 +2651,10 @@ def cat(self, others=None, sep=None, na_rep=None, join="left"):
     the columns during the split.
 
     >>> s.str.split(expand=True)
-                                                   0     1     2        3
-    0                                           this    is     a  regular
-    1  https://docs.python.org/3/tutorial/index.html  None  None     None
-    2                                            NaN   NaN   NaN      NaN \
-                 4
-    0     sentence
-    1         None
-    2          NaN
+                                                   0     1     2        3         4
+    0                                           this    is     a  regular  sentence
+    1  https://docs.python.org/3/tutorial/index.html  None  None     None      None
+    2                                            NaN   NaN   NaN      NaN       NaN
 
     For slightly more complex use cases like splitting the html document name
     from a url, a combination of parameter settings can be used.
@@ -2658,7 +2669,9 @@ def cat(self, others=None, sep=None, na_rep=None, join="left"):
     expressions.
 
     >>> s = pd.Series(["1+1=2"])
-
+    >>> s
+    0    1+1=2
+    dtype: object
     >>> s.str.split(r"\+|=", expand=True)
          0    1    2
     0    1    1    2
@@ -2750,7 +2763,7 @@ def rsplit(self, pat=None, n=-1, expand=False):
     >>> idx.str.partition()
     MultiIndex([('X', ' ', '123'),
                 ('Y', ' ', '999')],
-               dtype='object')
+               )
 
     Or an index with tuples with ``expand=False``: