'x' not in list while iterating over list

Question

What I am attempting to do is iterate over a list of comments, remove the current comment that has been added to a value called cText , and if cText goes over 9000 characters make a recursive call into the same function and add it's returned value into botComments . I'm also attempting to merge the returned botComments list from a recursed function to the top-most botComments list with botComments + repliesToComments(comments, author) though I don't know if I'm doing anything right. Oddly, it also seems it can't find a comment in a list that for-sure has the comment throwing the exception I pasted below. I was horrible at recursion during my AP Comp-Sci class though I wish to learn what I'm doing wrong from whomever can fix my mess of code below. Thanks :)

Here's my current exception:

Traceback (most recent call last):
  File "C:\Users\Josh\Desktop\bot.py", line 62, in <module>
    print(repliesToComments(submission.comments, submission.author.name))
  File "C:\Users\Josh\Desktop\bot.py", line 36, in repliesToComments
    botComments + repliesToComments(comments, author)
  File "C:\Users\Josh\Desktop\bot.py", line 39, in repliesToComments
    comments.remove(comment)
ValueError: list.remove(x): x not in list

Here's my code:

def repliesToComments(comments, author):
    botComments = []
    multiReplies = False

    cText = "Here is a list of all the comments /u/" + author + ''' has submitted to top-level comments:
***
Original Comment | /u/''' + author + ''''s Reply
---------|---------
'''

    for comment in comments[:]:
        if (hasattr(comment, "replies")):
            for comment2 in comment.replies:
                if (hasattr(comment2, "author") and comment2.author.name == author):
                    oCommentLink = "[" + comment.body.replace("\n", "")[:50] + "](" + submission.permalink + "" + comment2.parent_id.replace("t1_", "") + ")..."
                    rCommentLink = "[" + comment2.body.replace("\n", "")[:50] + "](" + submission.permalink + "" + comment2.name.replace("t1_", "") + ")..."
                    if (len(cText) + len(oCommentLink + " | " + rCommentLink + "\n") > 9000): #Stop here to make sure we don't go over 10000 char limit!
                        multiReplies = True
                        cText += '''
***
[FAQ](http://pastebin.com/raw.php?i=wUGmE8X5) | Generated at ''' + datetime.datetime.now().strftime("%Y-%m-%d %H:%M:%S") + " PST" + " | *This comment only shows a partial amount of OPs total replies due to character limit. The rest are shown in a reply to this comment.*"
                        botComments.append(cText)
                        botComments + repliesToComments(comments, author)
                        break
                    cText += oCommentLink + " | " + rCommentLink + "\n"
        comments.remove(comment)

    if (multiReplies == False):
        cText += '''
***
[FAQ](http://pastebin.com/raw.php?i=wUGmE8X5) | Generated at ''' + datetime.datetime.now().strftime("%Y-%m-%d %H:%M:%S") + " PST"

    botComments.append(cText)
    return botComments

Answer 1

You are calling repliesToComments() recursively, but with the exact same arguments . This can only lead to problems.

Your recursive call is removing entries from the same list, and when it returns, those entries will still be gone . But because you loop over a copy of the list, your outer call won't be updated and try to remove comments the inner recursive call removed already .

Perhaps you wanted to call repliesToComments() for a different set of comments when recursing? I suspect you meant to call it for comment.replies instead?

Another problem your code has is that you ignore the return value of the recursive call:

botComments + repliesToComments(comments, author)

This adds the list botComments and the return value of the recursive call, creating a new list, which you then drop to the floor by not assigning it to a variable. You probably want to use:

botComments += repliesToComments(comments, author)

instead.