Restructure code to avoid unnecessary list slicing by using rsplit.

IPython/utils/importstring.py

@@ -1,62 +1,50 b''
 # encoding: utf-8
 """
 A simple utility to import something by its string name.
 
 Authors:
 
 * Brian Granger
 """
 
 #-----------------------------------------------------------------------------
 #  Copyright (C) 2008-2011  The IPython Development Team
 #
 #  Distributed under the terms of the BSD License.  The full license is in
 #  the file COPYING, distributed as part of this software.
 #-----------------------------------------------------------------------------
 
 #-----------------------------------------------------------------------------
 # Functions and classes
 #-----------------------------------------------------------------------------
 
 def import_item(name):
     """Import and return ``bar`` given the string ``foo.bar``.
 
     Calling ``bar = import_item("foo.bar")`` is the functional equivalent of
     executing the code ``from foo import bar``.
 
     Parameters
     ----------
     name : string
       The fully qualified name of the module/package being imported.
 
     Returns
     -------
     mod : module object
        The module that was imported.
     """
       
-    package = '.'.join(name.split('.')[0:-1])
-    obj = name.split('.')[-1]
-    
-    # Note: the original code for this was the following.  We've left it
-    # visible for now in case the new implementation shows any problems down
-    # the road, to make it easier on anyone looking for a problem.  This code
-    # should be removed once we're comfortable we didn't break anything.
-    
-    ## execString = 'from %s import %s' % (package, obj)
-    ## try:
-    ##     exec execString
-    ## except SyntaxError:
-    ##     raise ImportError("Invalid class specification: %s" % name)
-    ## exec 'temp = %s' % obj
-    ## return temp
-
-    if package:
+    parts = name.rsplit('.', 1)
+    if len(parts) == 2:
+        # called with 'foo.bar....'
+        package, obj = parts
         module = __import__(package,fromlist=[obj])
         try:
             pak = module.__dict__[obj]
         except KeyError:
             raise ImportError('No module named %s' % obj)
         return pak
     else:
-        return __import__(obj)
+        # called with un-dotted string
+        return __import__(parts[0])