random.shuffle（someLazyMap）

Question

I'm currently trying to train my Python NLTK Part-Of-Speech Tagger to tag German text correctly. In order to do so I'm using of the ClassifiedBasedGermanTagger, from:

https://github.com/ptnplanet/NLTK-Contributions/tree/master/ClassifierBasedGermanTagger

and a training corpus from this website:

http://www.ims.uni-stuttgart.de/forschung/ressourcen/korpora/TIGERCorpus/download/start.html (TIGER Corpus Release 2.2 (July 2012))

I found out that there is a pretty well written tutorial on how to go about this. So right now all I'm trying to do is to recreate the code:

https://datascience.blog.wzb.eu/2016/07/13/accurate-part-of-speech-tagging-of-german-texts-with-nltk/

The part that doesn't work for me is this:

tagged_sents = corp.tagged_sents() 
random.shuffle(tagged_sents)

The error I get looks like this:

File "C:\somedude\lib\random.py", line 274, in shuffle
    x[i], x[j] = x[j], x[i]
TypeError: 'LazyMap' object does not support item assignment

Do you have a workaround for this or even an explanation as to why it supposedly worked for the gentleman that wrote that tutorial and why it shows an error for me? Currently I'm using Python 3.

Thank you all very much in advance.

Answer 1

A little late, but maybe it helps someone else.

The author of the tutorial forgot the "list" as stated in the NLTK book: http://www.nltk.org/book/ch06.html#evaluation

so instead of

tagged_sents = corp.tagged_sents()

it must be:

tagged_sents = list(corp.tagged_sents())

Answer 2

tagged_sents = list(range(<some number>,<some number>))  # make sure some_nums is a list/mutable sequence
random.shuffle(tagged_sents)

You can find a solution here

https://teamtreehouse.com/community/randomshuffle-crashes-when-passed-a-range-somenums-randomshufflerange5250