DOC: Improved the docstring of Series.str.findall (pandas-dev#19982)

pandas/core/strings.py

@@ -898,23 +898,94 @@ def str_join(arr, sep):
 
 def str_findall(arr, pat, flags=0):
     """
-    Find all occurrences of pattern or regular expression in the
-    Series/Index. Equivalent to :func:`re.findall`.
+    Find all occurrences of pattern or regular expression in the Series/Index.
+
+    Equivalent to applying :func:`re.findall` to all the elements in the
+    Series/Index.
 
     Parameters
     ----------
     pat : string
-        Pattern or regular expression
-    flags : int, default 0 (no flags)
-        re module flags, e.g. re.IGNORECASE
+        Pattern or regular expression.
+    flags : int, default 0
+        ``re`` module flags, e.g. `re.IGNORECASE` (default is 0, which means
+        no flags).
 
     Returns
     -------
-    matches : Series/Index of lists
+    Series/Index of lists of strings
+        All non-overlapping matches of pattern or regular expression in each
+        string of this Series/Index.
 
     See Also
     --------
-    extractall : returns DataFrame with one column per capture group
+    count : Count occurrences of pattern or regular expression in each string
+        of the Series/Index.
+    extractall : For each string in the Series, extract groups from all matches
+        of regular expression and return a DataFrame with one row for each
+        match and one column for each group.
+    re.findall : The equivalent ``re`` function to all non-overlapping matches
+        of pattern or regular expression in string, as a list of strings.
+
+    Examples
+    --------
+
+    >>> s = pd.Series(['Lion', 'Monkey', 'Rabbit'])
+
+    The search for the pattern 'Monkey' returns one match:
+
+    >>> s.str.findall('Monkey')
+    0          []
+    1    [Monkey]
+    2          []
+    dtype: object
+
+    On the other hand, the search for the pattern 'MONKEY' doesn't return any
+    match:
+
+    >>> s.str.findall('MONKEY')
+    0    []
+    1    []
+    2    []
+    dtype: object
+
+    Flags can be added to the pattern or regular expression. For instance,
+    to find the pattern 'MONKEY' ignoring the case:
+
+    >>> import re
+    >>> s.str.findall('MONKEY', flags=re.IGNORECASE)
+    0          []
+    1    [Monkey]
+    2          []
+    dtype: object
+
+    When the pattern matches more than one string in the Series, all matches
+    are returned:
+
+    >>> s.str.findall('on')
+    0    [on]
+    1    [on]
+    2      []
+    dtype: object
+
+    Regular expressions are supported too. For instance, the search for all the
+    strings ending with the word 'on' is shown next:
+
+    >>> s.str.findall('on$')
+    0    [on]
+    1      []
+    2      []
+    dtype: object
+
+    If the pattern is found more than once in the same string, then a list of
+    multiple strings is returned:
+
+    >>> s.str.findall('b')
+    0        []
+    1        []
+    2    [b, b]
+    dtype: object
+
     """
     regex = re.compile(pat, flags=flags)
     return _na_map(regex.findall, arr)