Running Stanford POS tagger in NLTK leads to "not a valid Win32 application" on Windows - nltk

Question

I am trying to use stanford POS tagger in NLTK by the following code:
import nltk
from nltk.tag.stanford import POSTagger
st = POSTagger('E:\Assistant\models\english-bidirectional-distsim.tagger',
'E:\Assistant\stanford-postagger.jar')
st.tag('What is the airspeed of an unladen swallow?'.split())
and here is the output:
Traceback (most recent call last):
File "E:\J2EE\eclipse\WSNLP\nlp\src\tagger.py", line 5, in <module>
st.tag('What is the airspeed of an unladen swallow?'.split())
File "C:\Python34\lib\site-packages\nltk\tag\stanford.py", line 59, in tag
return self.tag_sents([tokens])[0]
File "C:\Python34\lib\site-packages\nltk\tag\stanford.py", line 81, in tag_sents
stdout=PIPE, stderr=PIPE)
File "C:\Python34\lib\site-packages\nltk\internals.py", line 153, in java
p = subprocess.Popen(cmd, stdin=stdin, stdout=stdout, stderr=stderr)
File "C:\Python34\lib\subprocess.py", line 858, in __init__
restore_signals, start_new_session)
File "C:\Python34\lib\subprocess.py", line 1111, in _execute_child
startupinfo)
OSError: [WinError 193] %1 is not a valid Win32 application
P.S. My java home is set and I have no problem with my java installation. Can someone explain what this error is talking about? It is not informative for me. Thanks in advance.

Answer 1

Looks like your Java installation is botched or missing.

Answer 2

It worked after a lot of trial and error:
It seems that NLTK Internal cannot find the java binary automatically on windows, so we need to identify it as follows:
import os
import nltk
from nltk.tag.stanford import POSTagger
os.environ['JAVA_HOME'] = r'C:\Program Files\Java\jre6\bin'
st = POSTagger('E:\stanford-postagger-2014-10-26\models\english-left3words-distsim.tagger',
'E:\stanford-postagger-2014-10-26\stanford-postagger.jar')
st.tag(nltk.word_tokenize('What is the airspeed of an unladen swallow?'))
As one of the gurus said to me: "don't forget to add "r" while working with "\" in strings."