When setting the value of a dictionary to an index i + 1 in a list, item is set to the the item after the last occurance of the value i

Question

with open("text.txt", "r") as file:
    contents = file.read().replace('\n',' ')
words = contents.split(' ')


wordsDict = {}
for i in range(len(words) - 1):
    wordsDict[words[i]] = words[i + 1]

def assemble():
    start = words[random.randint(0, len(words))]
    print(start.capitalize())


assemble()

I am currently creating a markov chain-esque project. When I ran this code, I had expected for the dictionary to look as follows:

(if text.txt read: the cat chased the rat while the dog chased the cat into the rat house)

{'the': 'cat', 'cat': 'chased', 'chased': 'the', 'the': 'rat', 'rat': 'while', 'while': 'the', 'the': 'dog', 'dog': 'chased', 'chased': 'the', 'the': 'cat', 'cat': 'into', 'into': 'the', 'the': 'rat', 'rat': 'house'}

but instead, I get

{'the': 'rat', 'cat': 'into', 'chased': 'the', 'rat': 'house', 'while': 'the', 'dog': 'chased', 'into': 'the'}

If you don't sense a pattern, it's that the value isn't just the next item in the array, it is the next item after the last occurance of the word. In this case, our first key & value pair is 'the': 'rat' because the last occurance of the is followed by rat.

I have no idea why this happens or how to fix it.

Answer 1

The dictionary you wanted isn't valid, you can't duplicate keys. You could try to do this with lists of lists instead.