Python中的分组列表

Question

我试图基于一个共同的索引将许多列表组合在一起。 公用索引是儒略日期（JD），我想将共享相同JD的其他列表中的所有其他时间合并到包含单个JD和所有各自时间的单个列表中。 但是，我不断收到“ TypeError：列表索引必须是整数，而不是元组”，而且我不确定为什么会发生这种情况。 我最初不是将变量“ list_of_lsts”分配给实际的列表列表，还是在循环中弄乱了某个地方。 我的最终结果如下：

['2014-158', '20:07:11.881', '20:43:04.546', '20:43:47.447', '21:11:08.997', '21:11:16.697', '21:22:07.717']
['2014-163', '17:12:09.071', '17:38:08.219', '17:38:28.310', '17:59:25.649','18:05:59.536', '18:09:53.243','18:13:47.671', '18:16:53.976', '18:20:31.538', '18:23:02.243']

我将在许多朱利安日期中执行此操作，因此循环是必要的。 我是一名新程序员，并且大多数都是Python 2.7.8的新手，所以请原谅您的无知和大量错误。 谢谢。

lst_of_lsts = (['2014-158', '20:07:11.881', '20:43:04.546']
               ['2014-158', '20:43:47.447', '21:11:08.997']
               ['2014-158', '21:11:16.697', '21:22:07.717']
               ['2014-163', '17:12:09.071', '17:38:08.219']
               ['2014-163', '17:38:28.310', '17:59:25.649']
               ['2014-163', '18:05:59.536', '18:09:53.243']
               ['2014-163', '18:13:47.671', '18:16:53.976']
               ['2014-163', '18:20:31.538', '18:23:02.243'])


def merge_subs(lst_of_lsts):
    res = []
    for row in lst_of_lsts:
        for i, resrow in enumerate(res):
            if row[0]==resrow[0]:
                res[i] += row[1:]
                break
            else:
                res.append(row)
        return res

Answer 1

改成

lst_of_lsts = (['2014-158', '20:07:11.881', '20:43:04.546'],
['2014-158', '20:43:47.447', '21:11:08.997'],
['2014-158', '21:11:16.697', '21:22:07.717'],
['2014-163', '17:12:09.071', '17:38:08.219'],
['2014-163', '17:38:28.310', '17:59:25.649'],
['2014-163', '18:05:59.536', '18:09:53.243'],
['2014-163', '18:13:47.671', '18:16:53.976'],
['2014-163', '18:20:31.538', '18:23:02.243'])

也就是说，您缺少逗号。

我建议的另一个变化是：

for i, resrow in enumerate(res):
        if row[0]==resrow[0]:
            res[i] += row[1:]

这里的res[i]和resrow是相同的东西-更改一个将更改另一个。 无需同时使用它们。 相反做

for resrow in res:
    if row[0] == resrow[0]:
        resrow += row[1:]

另外-按照当前缩进，如果if失败，则else将不会完成。 相反，它将在for循环之后完成。 我认为那不是您想要的。

确实，您想使用字典。

def merge_subs2(lst_of_lsts):
    date_dict = {}
    for row in lst_of_lsts:
        if row[0] not in date_dict:
            date_dict[row[0]] = [row[0]] #note that I'm putting row[0] here already.
        date_dict[row[0]].extend(row[1:])
    returnlist = date_dict.values()
    returnlist.sort()   #sorting because dicts don't have an order to them.
    return returnlist

Answer 2

def merge_subs(L):
    dates = {}
    for sub in L:
        date = sub[0]
        if date not in dates:
            dates[date] = []
        dates[date].extend(sub[1:])
    answer = []
    for date in sorted(dates):
        answer.append([date] + dates[date])
    return answer

输出：

In [28]: lst_of_lsts = (['2014-158', '20:07:11.881', '20:43:04.546'],
['2014-158', '20:43:47.447', '21:11:08.997'],
['2014-158', '21:11:16.697', '21:22:07.717'],
['2014-163', '17:12:09.071', '17:38:08.219'],
['2014-163', '17:38:28.310', '17:59:25.649'],
['2014-163', '18:05:59.536', '18:09:53.243'],
['2014-163', '18:13:47.671', '18:16:53.976'],
['2014-163', '18:20:31.538', '18:23:02.243'])

In [29]: merge_subs(lst_of_lsts)
Out[29]: [['2014-158', '20:07:11.881', '20:43:04.546', '20:43:47.447', '21:11:08.997', '21:11:16.697', '21:22:07.717'], 
          ['2014-163', '17:12:09.071', '17:38:08.219', '17:38:28.310', '17:59:25.649', '18:05:59.536', '18:09:53.243', '18:13:47.671', '18:16:53.976', '18:20:31.538', '18:23:02.243']]