diff --git a/docsite/rst/playbooks_variables.rst b/docsite/rst/playbooks_variables.rst index d3314fbab0..b1ad224562 100644 --- a/docsite/rst/playbooks_variables.rst +++ b/docsite/rst/playbooks_variables.rst @@ -36,9 +36,25 @@ Variable names should be letters, numbers, and underscores. Variables should al ``foo-port``, ``foo port``, ``foo.port`` and ``12`` are not valid variable names. -When you work with more complex data types like dictionaries and sets note that you should avoid keys which are valid attributes for a data type in Python. -As a rule of thump, avoid all key names that start and end with two underscores for example ``__do_not_use__``. -Also avoid any of the following words: +YAML also supports dictionaries which map keys to values. For instance:: + + foo: + field1: one + field2: two + +You can then reference a specific field in the dictionary using either bracket +notation or dot notation:: + + foo['field1'] + foo.field1 + +These will both reference the same value ("one"). However, if you choose to +use dot notation be aware that some keys can cause problems because they +collide with attributes and methods of python dictionaries. You should use +bracket notation instead of dot notation if you use keys which start and end +with two underscores (Those are reserved for special meanings in python) or +are any of the known public attributes: + ``add``, ``append``, ``as_integer_ratio``, ``bit_length``, ``capitalize``, ``center``, ``clear``, ``conjugate``, ``copy``, ``count``, ``decode``, ``denominator``, ``difference``, ``difference_update``, ``discard``, ``encode``, ``endswith``, ``expandtabs``, ``extend``, ``find``, ``format``, ``fromhex``, ``fromkeys``, ``get``, ``has_key``, ``hex``, ``imag``, ``index``, ``insert``, ``intersection``, ``intersection_update``, ``isalnum``, ``isalpha``, ``isdecimal``, ``isdigit``, ``isdisjoint``, ``is_integer``, ``islower``, ``isnumeric``, ``isspace``, ``issubset``, ``issuperset``, ``istitle``, ``isupper``, ``items``, ``iteritems``, ``iterkeys``, ``itervalues``, ``join``, ``keys``, ``ljust``, ``lower``, ``lstrip``, ``numerator``, ``partition``, ``pop``, ``popitem``, ``real``, ``remove``, ``replace``, ``reverse``, ``rfind``, ``rindex``, ``rjust``, ``rpartition``, ``rsplit``, ``rstrip``, ``setdefault``, ``sort``, ``split``, ``splitlines``, ``startswith``, ``strip``, ``swapcase``, ``symmetric_difference``, ``symmetric_difference_update``, ``title``, ``translate``, ``union``, ``update``, ``upper``, ``values``, ``viewitems``, ``viewkeys``, ``viewvalues``, ``zfill``. .. _variables_in_inventory: