How to config nltk data directory from code?

Just change items of nltk.data.path, it's a simple list.

From the code, http://www.nltk.org/_modules/nltk/data.html:

``nltk:path``: Specifies the file stored in the NLTK data
 package at *path*.  NLTK will search for these files in the
 directories specified by ``nltk.data.path``.

Then within the code:

######################################################################
# Search Path
######################################################################

path = []
"""A list of directories where the NLTK data package might reside.
   These directories will be checked in order when looking for a
   resource in the data package.  Note that this allows users to
   substitute in their own versions of resources, if they have them
   (e.g., in their home directory under ~/nltk_data)."""

# User-specified locations:
path += [d for d in os.environ.get('NLTK_DATA', str('')).split(os.pathsep) if d]
if os.path.expanduser('~/') != '~/':
    path.append(os.path.expanduser(str('~/nltk_data')))

if sys.platform.startswith('win'):
    # Common locations on Windows:
    path += [
        str(r'C:\nltk_data'), str(r'D:\nltk_data'), str(r'E:\nltk_data'),
        os.path.join(sys.prefix, str('nltk_data')),
        os.path.join(sys.prefix, str('lib'), str('nltk_data')),
        os.path.join(os.environ.get(str('APPDATA'), str('C:\\')), str('nltk_data'))
    ]
else:
    # Common locations on UNIX & OS X:
    path += [
        str('/usr/share/nltk_data'),
        str('/usr/local/share/nltk_data'),
        str('/usr/lib/nltk_data'),
        str('/usr/local/lib/nltk_data')
    ]

To modify the path, simply append to the list of possible paths:

import nltk
nltk.data.path.append("/home/yourusername/whateverpath/")

Or in windows:

import nltk
nltk.data.path.append("C:\somewhere\farfar\away\path")

I use append, example

nltk.data.path.append('/libs/nltk_data/')