python - 在 Pandas 系列中找到第一个非零值

Question

我有一个数字 Pandas 系列，其中 601 行按日期索引，如下所示。在引入一些非零值之前，这些值都是零。这一点因每个系列而异，所以我想找到一种方法来找到第一个非零值的索引并从该点开始绘制。

Name: users, dtype: float64 dates
2015-08-17 14:29:59-04:00    18
2015-08-16 14:29:59-04:00     3
2015-08-15 14:29:59-04:00    11
2015-08-14 14:29:59-04:00    12
2015-08-13 14:29:59-04:00     8
2015-08-12 14:29:59-04:00    10
2015-08-11 14:29:59-04:00     6
2015-08-10 14:29:59-04:00     6
2015-08-09 14:29:59-04:00     7
2015-08-08 14:29:59-04:00     7
2015-08-07 14:29:59-04:00    13
2015-08-06 14:29:59-04:00    16
2015-08-05 14:29:59-04:00    12
2015-08-04 14:29:59-04:00    14
2015-08-03 14:29:59-04:00     5
2015-08-02 14:29:59-04:00     5
2015-08-01 14:29:59-04:00     8
2015-07-31 14:29:59-04:00     6
2015-07-30 14:29:59-04:00     7
2015-07-29 14:29:59-04:00     9
2015-07-28 14:29:59-04:00     7
2015-07-27 14:29:59-04:00     5
2015-07-26 14:29:59-04:00     4
2015-07-25 14:29:59-04:00     8
2015-07-24 14:29:59-04:00     8
2015-07-23 14:29:59-04:00     8
2015-07-22 14:29:59-04:00     9
2015-07-21 14:29:59-04:00     5
2015-07-20 14:29:59-04:00     7
2015-07-19 14:29:59-04:00     6
                             ..
2014-01-23 13:29:59-05:00     0
2014-01-22 13:29:59-05:00     0
2014-01-21 13:29:59-05:00     0
2014-01-20 13:29:59-05:00     0
2014-01-19 13:29:59-05:00     0
2014-01-18 13:29:59-05:00     0
2014-01-17 13:29:59-05:00     0
2014-01-16 13:29:59-05:00     0
2014-01-15 13:29:59-05:00     0
2014-01-14 13:29:59-05:00     0
2014-01-13 13:29:59-05:00     0
2014-01-12 13:29:59-05:00     0
2014-01-11 13:29:59-05:00     0
2014-01-10 13:29:59-05:00     0
2014-01-09 13:29:59-05:00     0
2014-01-08 13:29:59-05:00     0
2014-01-07 13:29:59-05:00     0
2014-01-06 13:29:59-05:00     0
2014-01-05 13:29:59-05:00     0
2014-01-04 13:29:59-05:00     0
2014-01-03 13:29:59-05:00     0
2014-01-02 13:29:59-05:00     0
2014-01-01 13:29:59-05:00     0
2013-12-31 13:29:59-05:00     0
2013-12-30 13:29:59-05:00     0
2013-12-29 13:29:59-05:00     0
2013-12-28 13:29:59-05:00     0
2013-12-27 13:29:59-05:00     0
2013-12-26 13:29:59-05:00     0
2013-12-25 13:29:59-05:00     0

Answer 1

假设您的系列名为 s:

s = s.sort_index()
start = s.loc[s != 0].index
if len(start) > 0:
    filtered_series = s.ix[start[0]:]

您的数据似乎按时间向后排序(即最近的排在最前面)，所以我首先对索引进行排序。

然后我使用 loc 获取系列中非负值的索引值。如果此列表返回任何内容(它可能是一个空列表)，那么我将使用 .ix 从上面计算的第一个非零索引值到系列末尾对系列进行索引。