如何在字典中连接文本的连续单词？

Question

I have to connect consecutive words of a text in a dictionary.

The text is:

text = "Hello world I am Josh"

The dictionary would be:

dict = {Hello:[world], world:[Hello, I], I:[am, world], am:[I, Josh], Josh:[am]} 

The keys are all the words in the text, the values are the consecutive words. Anyone has an idea to abstain this?

1. I would split the text. To obtain all the words in a list.
2. I would use the words as the keys of the dictionary.
3. ?

Answer 1

Using the pairwise recipe from itertools :

def pairwise(iterable):
    a, b = tee(iterable)
    next(b, None)
    return izip(a, b)

adjacent = collections.defaultdict(list)
for left, right in pairwise(text.split()):
    adjacent[right].append(left)
    adjacent[left].append(right)

Your question doesn't consider the possibility that a word appears in the sentence more than once. You might want a set rather than a list of adjacent words. Punctuation in the sentence could also ruin your day, so depending on your requirements you might need to do more than just split() .