My list is not a tuple, why is the error saying otherwise?? :(

Question

I keep having the same related error on my code and just can't figure out where is the issue. Tried all I could find online but it doesn't seems to work. Here is the bit of code. (I know it's probably not optimized but that's not the main issue here for me) also I'm on Python 3.9.1

def init():         # créer la liste de données
    liste = []
    liste_lettre = []
    for x in range(len(texte)-1):

        lettre_init = []
        liste_poss = []

        if texte[x][0] not in liste_lettre:

            liste_lettre.append(texte[x][0])
            lettre_init = texte[x][0]

            for i in range(len(texte)-1):
                for j in range(len(texte[i])):

                    if texte[i][j] == lettre_init:

                        if j == len(texte[i]):
                            liste_poss += (" ")

                        else:
                            liste_poss.append(texte[i][j+1])
                            print(hasattr(liste_poss, "append"))
                            

                liste_poss = lettre_init, liste_poss
                liste.append(liste_poss)
    return liste

ok so to explain what my code is about :

I'm trying to create a function to store the consecutive iterations of letters from a given text (texte) into an array (liste). texte is an array of words

The function checks for every letter of every word of texte if the letter has already been verified. If not, every time it sees the given letter (stored in lettre_init) in a word in texte, if this is the last letter of the word, it will add a space (" ") to the liste liste_poss; if not the last letter of the word, it will add to liste_poss the following letter in the word. after verifying texte entirely, a list consisting of the letter verified (lettre_init) and all the following letters (liste_poss) is added to the array liste. at the end, liste is returned.

I keep having the error AttributeError: 'tuple' object has no attribute 'append' for the line liste_poss.append(texte[i][j+1])

I verified texte and liste_poss with hasattr(liste_poss, "append") and it returned True I tried liste_poss += (texte[i][j+1]) but then the error is TypeError: can only concatenate tuple (not "str") to tuple.

The issue seems to be related to an object being a tuple, but I just can't find what's the problem? If you have any idea please help me, I'm lost.

Answer 1

You create liste_poss as a list:

liste_poss = []

But then on the last step of the outer for loop, you reassign it to a tuple:

liste_poss = lettre_init, liste_poss

So yes, it is a tuple.