使用 pandas 基於另一列過濾 dataframe 值

Question

有 df 值。

name     last_date                     submission_date

mike  2020-04-10 02:22:22.222   2020-04-01 02:22:22.222
mike  2020-04-10 02:22:22.222   2020-04-08 02:22:22.222
mike  2020-04-10 02:22:22.222   2020-04-16 02:22:22.222

ross  2020-04-16 02:22:22.222   2020-04-18 02:22:22.222
ross  2020-04-16 02:22:22.222   2020-04-19 02:22:22.222
ross  2020-04-16 02:22:22.222   2020-04-20 02:22:22.222
ross  2020-04-16 02:22:22.222   2020-04-15 02:22:22.222

carter 2020-04-22 02:22:22.222   2020-04-28 02:22:22.222
carter 2020-04-22 02:22:22.222   2020-04-15 02:22:22.222
carter 2020-04-22 02:22:22.222   2020-04-19 02:22:22.222
carter 2020-04-22 02:22:22.222   2020-04-21 02:22:22.222

根據 last_date 過濾值。 如果 submit_date 大於 last_date 則排除它的值

預期 output：

name     last_date                     submission_date

mike  2020-04-10 02:22:22.222   2020-04-01 02:22:22.222
mike  2020-04-10 02:22:22.222   2020-04-08 02:22:22.222

ross  2020-04-16 02:22:22.222   2020-04-15 02:22:22.222

carter 2020-04-22 02:22:22.222   2020-04-15 02:22:22.222
carter 2020-04-22 02:22:22.222   2020-04-19 02:22:22.222
carter 2020-04-22 02:22:22.222   2020-04-21 02:22:22.222

Answer 1

您可以query dataframe ，其中submission_date小於或等於last_date ，這將返回滿足條件的行並過濾掉 rest：

df.query("last_date>=submission_date")

---

    name                 last_date         submission_date
0   mike   2020-04-10 02:22:22.222 2020-04-01 02:22:22.222
1   mike   2020-04-10 02:22:22.222 2020-04-08 02:22:22.222
2   ross   2020-04-16 02:22:22.222 2020-04-15 02:22:22.222
3  carter  2020-04-22 02:22:22.222 2020-04-15 02:22:22.222
4  carter  2020-04-22 02:22:22.222 2020-04-19 02:22:22.222
5  carter  2020-04-22 02:22:22.222 2020-04-21 02:22:22.222