option callback on value change, use an option to control use_inf_as_null

RELEASE.rst

@@ -99,7 +99,7 @@ pandas 0.10.0
     instead. This is a legacy hack and can lead to subtle bugs.
   - inf/-inf are no longer considered as NA by isnull/notnull. To be clear, this
     is legacy cruft from early pandas. This behavior can be globally re-enabled
-    using pandas.core.common.use_inf_as_na (#2050, #1919)
+    using the new option ``mode.use_inf_as_null`` (#2050, #1919)
   - ``pandas.merge`` will now default to ``sort=False``. For many use cases
     sorting the join keys is not necessary, and doing it by default is wasteful
   - ``names`` handling in file parsing: if explicit column `names` passed,

doc/source/missing_data.rst

@@ -61,7 +61,7 @@ arise and we wish to also consider that "missing" or "null".
 
 Until recently, for legacy reasons ``inf`` and ``-inf`` were also
 considered to be "null" in computations. This is no longer the case by
-default; use the :func: `~pandas.core.common.use_inf_as_null` function to recover it.
+default; use the ``mode.use_inf_as_null`` option to recover it.
 
 .. _missing.isnull:
 

pandas/core/common.py

@@ -94,8 +94,8 @@ def isnull_old(obj):
     else:
         return obj is None
 
-def use_inf_as_null(flag):
-    '''
+def _use_inf_as_null(key):
+    '''Option change callback for null/inf behaviour
     Choose which replacement for numpy.isnan / -numpy.isfinite is used.
 
     Parameters
@@ -113,6 +113,7 @@ def use_inf_as_null(flag):
     * http://stackoverflow.com/questions/4859217/
       programmatically-creating-variables-in-python/4859312#4859312
     '''
+    flag = get_option(key)
     if flag == True:
         globals()['isnull'] = isnull_old
     else:
@@ -1179,7 +1180,7 @@ def in_interactive_session():
     returns True if running under python/ipython interactive shell
     """
     import __main__ as main
-    return not hasattr(main, '__file__') or get_option('test.interactive')
+    return not hasattr(main, '__file__') or get_option('mode.sim_interactive')
 
 def in_qtconsole():
     """

pandas/core/config.py

@@ -25,7 +25,9 @@
 - all options in a certain sub - namespace can be reset at once.
 - the user can set / get / reset or ask for the description of an option.
 - a developer can register and mark an option as deprecated.
-
+- you can register a callback to be invoked when the the option value
+  is set or reset. Changing the stored value is considered misuse, but
+  is not verboten.
 
 Implementation
 ==============
@@ -54,7 +56,7 @@
 import warnings
 
 DeprecatedOption = namedtuple('DeprecatedOption', 'key msg rkey removal_ver')
-RegisteredOption = namedtuple('RegisteredOption', 'key defval doc validator')
+RegisteredOption = namedtuple('RegisteredOption', 'key defval doc validator cb')
 
 _deprecated_options = {}  # holds deprecated option metdata
 _registered_options = {}  # holds registered option metdata
@@ -105,6 +107,9 @@ def _set_option(pat, value):
     root, k = _get_root(key)
     root[k] = value
 
+    if o and o.cb:
+        o.cb(key)
+
 
 def _describe_option(pat='', _print_desc=True):
 
@@ -270,7 +275,7 @@ def __doc__(self):
 ######################################################
 # Functions for use by pandas developers, in addition to User - api
 
-def register_option(key, defval, doc='', validator=None):
+def register_option(key, defval, doc='', validator=None, cb=None):
     """Register an option in the package-wide pandas config object
 
     Parameters
@@ -280,6 +285,9 @@ def register_option(key, defval, doc='', validator=None):
     doc       - a string description of the option
     validator - a function of a single argument, should raise `ValueError` if
                 called with a value which is not a legal value for the option.
+    cb        - a function of a single argument "key", which is called
+                immediately after an option value is set/reset. key is
+                the full name of the option.
 
     Returns
     -------
@@ -321,7 +329,7 @@ def register_option(key, defval, doc='', validator=None):
 
     # save the option metadata
     _registered_options[key] = RegisteredOption(key=key, defval=defval,
-            doc=doc, validator=validator)
+            doc=doc, validator=validator,cb=cb)
 
 
 def deprecate_option(key, msg=None, rkey=None, removal_ver=None):

pandas/core/config_init.py

@@ -139,10 +139,27 @@
     cf.register_option('expand_frame_repr', True, pc_expand_repr_doc)
     cf.register_option('line_width', 80, pc_line_width_doc)
 
-tc_interactive_doc="""
+tc_sim_interactive_doc="""
 : boolean
     Default False
     Whether to simulate interactive mode for purposes of testing
 """
-with cf.config_prefix('test'):
-    cf.register_option('interactive', False, tc_interactive_doc)
+with cf.config_prefix('mode'):
+    cf.register_option('sim_interactive', False, tc_sim_interactive_doc)
+
+use_inf_as_null_doc="""
+: boolean
+    True means treat None, NaN, INF, -INF as null (old way),
+    False means None and NaN are null, but INF, -INF are not null
+    (new way).
+"""
+
+# we don't want to start importing evrything at the global context level
+# or we'll hit circular deps.
+def use_inf_as_null_cb(key):
+    from pandas.core.common import _use_inf_as_null
+    _use_inf_as_null(key)
+
+with cf.config_prefix('mode'):
+    cf.register_option('use_inf_as_null', False, use_inf_as_null_doc,
+                       cb=use_inf_as_null_cb)

pandas/tests/test_common.py

@@ -5,9 +5,10 @@
 import unittest
 
 from pandas import Series, DataFrame, date_range, DatetimeIndex
-from pandas.core.common import notnull, isnull, use_inf_as_null
+from pandas.core.common import notnull, isnull
 import pandas.core.common as com
 import pandas.util.testing as tm
+import pandas.core.config as cf
 
 import numpy as np
 
@@ -29,15 +30,15 @@ def test_notnull():
     assert not notnull(None)
     assert not notnull(np.NaN)
 
-    use_inf_as_null(False)
+    cf.set_option("mode.use_inf_as_null",False)
     assert notnull(np.inf)
     assert notnull(-np.inf)
 
-    use_inf_as_null(True)
+    cf.set_option("mode.use_inf_as_null",True)
     assert not notnull(np.inf)
     assert not notnull(-np.inf)
 
-    use_inf_as_null(False)
+    cf.set_option("mode.use_inf_as_null",False)
 
     float_series = Series(np.random.randn(5))
     obj_series = Series(np.random.randn(5), dtype=object)

pandas/tests/test_config.py

@@ -282,6 +282,31 @@ def test_config_prefix(self):
             self.assertEqual(self.cf.get_option('a'), 1)
             self.assertEqual(self.cf.get_option('b'), 2)
 
+    def test_callback(self):
+        k=[None]
+        v=[None]
+        def callback(key):
+            k.append(key)
+            v.append(self.cf.get_option(key))
+
+        self.cf.register_option('d.a', 'foo',cb=callback)
+        self.cf.register_option('d.b', 'foo',cb=callback)
+
+        del k[-1],v[-1]
+        self.cf.set_option("d.a","fooz")
+        self.assertEqual(k[-1],"d.a")
+        self.assertEqual(v[-1],"fooz")
+
+        del k[-1],v[-1]
+        self.cf.set_option("d.b","boo")
+        self.assertEqual(k[-1],"d.b")
+        self.assertEqual(v[-1],"boo")
+
+        del k[-1],v[-1]
+        self.cf.reset_option("d.b")
+        self.assertEqual(k[-1],"d.b")
+
+
 
 # fmt.reset_printoptions and fmt.set_printoptions were altered
 # to use core.config, test_format exercises those paths.

pandas/tests/test_format.py

@@ -112,11 +112,11 @@ def test_repr_should_return_str (self):
         self.assertTrue(type(df.__repr__() == str)) # both py2 / 3
 
     def test_repr_no_backslash(self):
-        pd.set_option('test.interactive', True)
+        pd.set_option('mode.sim_interactive', True)
         df = DataFrame(np.random.randn(10, 4))
 
         self.assertTrue('\\' not in repr(df))
-        pd.reset_option('test.interactive')
+        pd.reset_option('mode.sim_interactive')
 
     def test_to_string_repr_unicode(self):
         buf = StringIO()
@@ -409,7 +409,7 @@ def test_frame_info_encoding(self):
         fmt.set_printoptions(max_rows=200)
 
     def test_wide_repr(self):
-        set_option('test.interactive', True)
+        set_option('mode.sim_interactive', True)
         col = lambda l, k: [tm.rands(k) for _ in xrange(l)]
         df = DataFrame([col(20, 25) for _ in range(10)])
         set_option('print.expand_frame_repr', False)
@@ -423,19 +423,19 @@ def test_wide_repr(self):
         self.assert_(len(wider_repr) < len(wide_repr))
 
         reset_option('print.expand_frame_repr')
-        set_option('test.interactive', False)
+        set_option('mode.sim_interactive', False)
         set_option('print.line_width', 80)
 
     def test_wide_repr_wide_columns(self):
-        set_option('test.interactive', True)
+        set_option('mode.sim_interactive', True)
         df = DataFrame(randn(5, 3), columns=['a' * 90, 'b' * 90, 'c' * 90])
         rep_str = repr(df)
 
         self.assert_(len(rep_str.splitlines()) == 20)
-        reset_option('test.interactive')
+        reset_option('mode.sim_interactive')
 
     def test_wide_repr_named(self):
-        set_option('test.interactive', True)
+        set_option('mode.sim_interactive', True)
         col = lambda l, k: [tm.rands(k) for _ in xrange(l)]
         df = DataFrame([col(20, 25) for _ in range(10)])
         df.index.name = 'DataFrame Index'
@@ -454,11 +454,11 @@ def test_wide_repr_named(self):
             self.assert_('DataFrame Index' in line)
 
         reset_option('print.expand_frame_repr')
-        set_option('test.interactive', False)
+        set_option('mode.sim_interactive', False)
         set_option('print.line_width', 80)
 
     def test_wide_repr_multiindex(self):
-        set_option('test.interactive', True)
+        set_option('mode.sim_interactive', True)
         col = lambda l, k: [tm.rands(k) for _ in xrange(l)]
         midx = pandas.MultiIndex.from_arrays([np.array(col(10, 5)),
                                               np.array(col(10, 5))])
@@ -479,11 +479,11 @@ def test_wide_repr_multiindex(self):
             self.assert_('Level 0 Level 1' in line)
 
         reset_option('print.expand_frame_repr')
-        set_option('test.interactive', False)
+        set_option('mode.sim_interactive', False)
         set_option('print.line_width', 80)
 
     def test_wide_repr_multiindex_cols(self):
-        set_option('test.interactive', True)
+        set_option('mode.sim_interactive', True)
         col = lambda l, k: [tm.rands(k) for _ in xrange(l)]
         midx = pandas.MultiIndex.from_arrays([np.array(col(10, 5)),
                                               np.array(col(10, 5))])
@@ -505,11 +505,11 @@ def test_wide_repr_multiindex_cols(self):
         self.assert_(len(wide_repr.splitlines()) == 14 * 10 - 1)
 
         reset_option('print.expand_frame_repr')
-        set_option('test.interactive', False)
+        set_option('mode.sim_interactive', False)
         set_option('print.line_width', 80)
 
     def test_wide_repr_unicode(self):
-        set_option('test.interactive', True)
+        set_option('mode.sim_interactive', True)
         col = lambda l, k: [tm.randu(k) for _ in xrange(l)]
         df = DataFrame([col(20, 25) for _ in range(10)])
         set_option('print.expand_frame_repr', False)
@@ -523,18 +523,18 @@ def test_wide_repr_unicode(self):
         self.assert_(len(wider_repr) < len(wide_repr))
 
         reset_option('print.expand_frame_repr')
-        set_option('test.interactive', False)
+        set_option('mode.sim_interactive', False)
         set_option('print.line_width', 80)
 
     def test_wide_repr_wide_long_columns(self):
-        set_option('test.interactive', True)
+        set_option('mode.sim_interactive', True)
 
         df = DataFrame({'a': ['a'*30, 'b'*30], 'b': ['c'*70, 'd'*80]})
 
         result = repr(df)
         self.assertTrue('ccccc' in result)
         self.assertTrue('ddddd' in result)
-        set_option('test.interactive', False)
+        set_option('mode.sim_interactive', False)
 
     def test_to_string(self):
         from pandas import read_table