Revert or adjust some misfitting bracket notations as reviewed

Author: katrinleinweber

doc/source/getting_started/10min.rst

@@ -170,7 +170,7 @@ Getting
 ~~~~~~~
 
 Selecting a single column, which yields a ``Series``,
-equivalent to ``df['A']``:
+equivalent to ``d.A``:
 
 .. ipython:: python
 

doc/source/user_guide/enhancingperf.rst

@@ -475,7 +475,7 @@ These operations are supported by :func:`pandas.eval`:
 * Comparison operations, including chained comparisons, e.g., ``2 < df < df2``
 * Boolean operations, e.g., ``df < df2 and df3 < df4 or not df_bool``
 * ``list`` and ``tuple`` literals, e.g., ``[1, 2]`` or ``(1, 2)``
-* Attribute access, e.g., ``df['a']``
+* Attribute access, e.g., ``df.a``
 * Subscript expressions, e.g., ``df[0]``
 * Simple variable evaluation, e.g., ``pd.eval('df')`` (this is not very useful)
 * Math functions: `sin`, `cos`, `exp`, `log`, `expm1`, `log1p`,

doc/source/user_guide/indexing.rst

@@ -206,7 +206,7 @@ as an attribute:
 
 .. warning::
 
-   - You can use this access only if the index element is a valid Python identifier, e.g. ``s.1`` is not allowed, but neither is ``s['1']``.
+   - You can use this access only if the index element is a valid Python identifier, e.g. ``s.1`` is not allowed.
      See `here for an explanation of valid identifiers
      <https://docs.python.org/3/reference/lexical_analysis.html#identifiers>`__.
 
@@ -1362,8 +1362,10 @@ Of course, expressions can be arbitrarily complex too:
    shorter = df.query('a < b < c and (not bools) or bools > 2')
 
    # equivalent in pure Python
-   longer = df[(df['a'] < df['b']) & (df['b'] < df['c'])
-               & (~df['bools']) | (df['bools'] > 2)]
+   longer = df[(df['a'] < df['b'])
+               & (df['b'] < df['c'])
+               & (~df['bools'])
+               | (df['bools'] > 2)]
 
    shorter
    longer