pandas.Series.append() 添加新值作为额外列，而不是将其附加到系列的末尾

Question

我正在编写一个程序，它从 CSV 文件中读取 comment.ids 系列，将新的 comment.id 附加到系列，然后将新系列保存为 CSV。

这是我所拥有的：

def get_cache(path_=PATH_CACHE):
    """"
    If cache does not exist, it creates one. Otherwise, it loads the 
    cache into memory.
    """
    print('Searching for cache...')
    if os.path.exists(path_)==True:
        print('Cache exists')
        cache = pd.read_csv(path_)
        print('Cache loaded')
    else:
        print('Cache does not exist')
        cache = pd.Series(['test1', 'test2'], name='commentid', dtype=str)
        print('Cache created')

    return cache

def run(reddit, reply, cache, sub='test'):
    """
    Posts on the specified subreddit if a comment containing a keyword 
    is found. Updates cache in memory.
    """
    subreddit = reddit.subreddit(sub)
    comments = subreddit.comments(limit=25)

    print('Searching for comments...')

    for comment in comments:
        comment_text = comment.body
        isMatch = any(string in comment_text for string in MATCH_WORDS)
        if isMatch and comment.id not in cache.values:
            print('Comment found!')
            # comment.reply(reply)
            print('Replied!')
            cache = cache.append(pd.Series([comment.id], dtype=str),
                                 ignore_index=True)      

            print('{} added to cache'.format(comment.id))
        else:
            print('Skip')
          
    print('Done Searching \nCache:\n {}'.format(cache))

    return cache

def update_cache(cache, path_=PATH_CACHE):
    """
    Saves cache as csv to same path as it was loaded in from, replacing 
    the csv file.
    """
    cache.to_csv(path_, index=False)
    print('Cache saved as csv')

当找到新的comment.id 时，我得到cache 的以下内容：

其中gshiiiq 是在调用run() 时找到的comment.id。我希望将gshiiiq 附加到现有列的末尾，而不添加新列。

任何帮助将不胜感激。

Answer 1

作为 AsishM。在他的评论中指出，pd.read_csv() 默认返回一个数据框。我设置了squeeze=True，它返回一个系列。