*********************************
Analysis Tool --- :mod:`analyzer`
*********************************

.. automodule:: libshorttext.analyzer
        :members:
        :undoc-members:
        :inherited-members:
        :show-inheritance:


Analyzer and Other Auxiliary Classes
====================================

.. autoclass:: libshorttext.analyzer.Analyzer
        :members:
        :undoc-members:
        :inherited-members:
        :show-inheritance:

Auxiliary Classes
-----------------

.. currentmodule:: libshorttext.analyzer

:class:`Analyzer` has two auxiliary classes: :class:`InstanceSet` and 
:class:`TextInstance`. :class:`InstanceSet` is a set of instances. It is used to 
indicate which instances :class:`Analyzer` should consider. Each instance in 
:class:`InstanceSet` is a :class:`TextInstance` instance.


.. autoclass:: libshorttext.analyzer.InstanceSet
        :members:
        :undoc-members:
        :inherited-members:
        :show-inheritance:




.. autoclass:: libshorttext.analyzer.TextInstance
        :members: 
        :undoc-members:
        :inherited-members:
        :show-inheritance:


.. _selectorfunctions:

Built-in Instance Selector Functions
====================================

.. currentmodule:: libshorttext.analyzer

Four selector functions are defined in :mod:`analyzer`. They should be used with
:meth:`InstanceSet.select`.

.. autofunction:: reverse

.. autofunction:: sort_by_dec

.. autofunction:: subset

.. autofunction:: with_labels

.. autofunction:: wrong


User-defined Selector Functions
-------------------------------

Users can define a selector function by themselves. A selector function's
input is a list of :class:`TextInstance`, and the return value should be another
list of :class:`TextInstance`. For example, :func:`wrong` is equivalent to the 
following example::

        def wrong(insts):
            wrong_label = lambda inst: inst.true_y != inst.predicted_y
            wrong_insts = filter(wrong_label, insts)
            return list(wrong_insts)

Refer to :class:`TextInstance` for the instance members.

:mod:`analyzer` provides a function :func:`selectorize` to convert some simple 
`rules` to a selector function. The example above can be further simplified
by :func:`selectorize`.

.. autofunction:: selectorize