Using lists as VALUE in a dictionary

Question

UPDATE: I figured out my issue

gram = notesNumbers[i:(i+1)];

When I print gram it prints it as an array with only 1 value. For example it would print [55]. Later in my code im referencing gram, however its using the whole array instead of the one value inside of it. To make it work I had to do gram[0] But a much easier approach was to just rewrite the above code to:

gram = notesNumbers[i]

Now when I print gram it give me a value ex) 55

---

In my code

I understand people have had similar issues, but in my context how do I fix this!

Im trying to do some prediction based on markov chains.

I have a very simple program. I have used the library mido to get music notes. I have parsed it and have all the notes in an array called notesNumbers

the notesNumbers array output looks like this

[55, 62, 67, 74, 55, 62, 67, 74, 55, 62, 67, 74, 55, 62, 67, 74, 55, 62, 67, 74, 55, 62, 67, 74, 55, 62, 67, 74, 55, 48, 52, 55, 59, 67, 71, 67, 71, 67, 71, 59, 67, 71]

I then created a new empty dictionary called ngrams I have set a starting point for the markovchain as 88 noted by the variable currentGram

what I then proceed to do is to create the markov transition 'matrix'. I use my dictionary to create a key with a number, then for the value I create an array which holds every possible "next number" that occurs in the given notesNumber

What I should be seeing if I print ngrams would be something like this (example): {'88': ['45', '55', '67', '45', '45', '33', '77', '90'], '32': ['44', '76', '77'}

however when trying to add to my dictionary by iterating I get the error TypeError: unhashable type: 'list' python

I get the error in the line that contains

if not gram in ngrams:

Code is below:

from midiutil.MidiFile import MIDIFile
import random
import mido
from mido import MidiFile
from mido import MidiTrack


#ignore midi stuff
mid = MidiFile()
track = MidiTrack()
mid.tracks.append(track)

notesNumbers = []
#notesNumbers = notesNumbers2


ngrams= {}
#Parsing message to get the notes to be played
for msg in MidiFile('song.mid'):
    if (not msg.is_meta):
        if (msg.type == 'note_on'):
            notesNumbers.append(msg.note)



#print(notesNumbers)

#starting number I picked
currentGram = 88
#print notesNumbers


#myOtherString = "".join(str(elm) for elm in notesNumbers)
#print notesNumbers2
#currentGram = random.choice(myOtherString)


ngrams= {}
#print currentGram

print(len(notesNumbers))

#creating markov transition matrix without directly doing probabilty 
#Creating a dictionary, getting each number and the frequency of the following number 
for i in range(len(notesNumbers)):
    print("about to iterate")
    gram = notesNumbers[i:(i+1)];
    print(gram)
    print("finish iterate")
    lessthan = len(notesNumbers) - 1

    if not gram in ngrams:
        ngrams[gram] = []
    else:
        if (i < lessthan):
            nextgram = notesNumbers[i+1]

        ngrams[gram].append(nextgram)


print(ngrams)


result = []
result.append(currentGram)

#getting next state
for i in range(len(notesNumbers)):
    possibilites = ngrams[currentGram]

    #print possibilites

    nextChoice = random.choice(possibilites)
    #print nextChoice
    result.append(nextChoice)

    currentGram = nextChoice
print("Restult")
print result