I started to make a program that reorders the letters in a string
in different ways to practice some Python. I noticed that when using the .append() method in a for loop, only the last iteration was getting appended again and again. I searched for an explanation but all I could
find was as solution to my issue but no good explanation to why it works.

My original code is:

def foo(word):

wordlist = list(word)
wordlist_copy = wordlist.copy()

combinations = []
for char in wordlist:
    for i,let in enumerate(wordlist_copy):
        wordlist_copy[i] = char
        print(wordlist_copy)
        combinations.append(wordlist_copy)     
        
return combinations

The solution I found was to change line 11: combinations.append(wordlist_copy) to combinations.append(list(wordlist_copy)).

Why is it that using the list method fixes my issue? I am already appending the wordlist_copy list on each iteration of the loop, so I can’t understand how the method would do anything special here.