轉碼_將數字解碼爲英文單詞
# word_index is a dictionary mapping words to an integer index
# word_index 是一個將單詞映射爲整數索引的字典
word_index = imdb.get_word_index()
# We reverse it, 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[0]])
# 將評論解碼。注意，索引減去了 3，因爲 0、 1、 2
# 是爲“padding”（填充）、“start of sequence”（序
# 列開始）、“unknown”（未知詞）分別保留的索引