#! /usr/bin/env python3
#
def imdb_decode ( item = 20 ):

#*****************************************************************************80
#
## imdb_decode decodes a movie review from keras's IMDB database.
#
#  Licensing:
#
#    This code is distributed under the GNU LGPL license.
#
#  Modified:
#
#    12 November 2019
#
#  Author:
#
#    Original version by Francois Chollet;
#    This version by John Burkardt.
#
#  Reference:
#
#    Francois Chollet,
#    Deep Learning with Python,
#    Manning, 2018,
#    ISBN: 9781617294433.
#
#  Input:
#
#    integer item: the index of the review to be decoded.
#    0 <= item < 25000.
#
  import keras
  import numpy as np
  import platform
  
  print ( '' )
  print ( 'imdb_decode:' )
  print ( '  Python version: %s' % ( platform.python_version ( ) ) )
  print ( '  keras version: %s' % ( keras.__version__ ) )
  print ( '  Demonstrate how to decode a movie review from the IMDB dataset.' )
#
#  Import the movie review dataset.
#
  from keras.datasets import imdb
#
#  Load the movie review dataset.
#  Only take the first 10,000 most frequent words.
#
  ( train_data, train_labels ), ( test_data, test_labels ) = \
    imdb.load_data ( num_words = 10000 )
#
#  As an example, list a data item and its label.
#  0 means a negative review, and 1 means a positive review.
#
  print ( '' )
  print ( '  Data item #', item )
  print ( '' )
  print ( train_data[item] )
  print ( '' )
  print ( '  Label (0=negative, 1=positive):' )
  print ( '' )
  print ( train_labels[item] )
#
#  Show how to recover the actual words of a review from the word index.
#  word_index is a dictionary mapping words to an integer index.
#
  word_index = imdb.get_word_index()
#
#  We create a reverse dictionary, mapping integer indices to words.
#
  reverse_word_index = dict ( [(value, key) for (key, value) in word_index.items()] )
#
#  We decode the review; note that our indices were offset by 3
#  because 0, 1 and 2 are reserved indices for "padding", 
#  "start of sequence", and "unknown".
#
  decoded_review = ' '.join([reverse_word_index.get(i - 3, '?') for i in train_data[item]])

  print ( '' )
  print ( '  Decoded review #', item )
  print ( '' )
  print ( decoded_review )
#
#  Terminate.
#
  print ( '' )
  print ( 'imdb_decode:' )
  print ( '  Normal end of execution.' )
  return

def timestamp ( ):

#*****************************************************************************80
#
## TIMESTAMP prints the date as a timestamp.
#
#  Licensing:
#
#    This code is distributed under the GNU LGPL license. 
#
#  Modified:
#
#    06 April 2013
#
#  Author:
#
#    John Burkardt
#
  import time

  t = time.time ( )
  print ( time.ctime ( t ) )

  return None

if ( __name__ == '__main__' ):
  timestamp ( )
  imdb_decode ( 10 )
  timestamp ( )