IPython/utils/importstring.py

# 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."""
    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:
        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)