如何在 pandas 中的 NaN 前后 select 行？

Question

我有一个如下所示的数据框：

    Name      Age       Job         
0   Alex      20        Student
1   Sara      21        Doctor
2   john      23        NaN
3   kevin     22        Teacher
4   Rosa      20        senior manager
5   johanes   25        Dentist
6   lina      23        Student
7   yaser     25        Pilot
8   jason     20        Manager
9   Ali       23        NaN
10  Ahmad     21        Professor
11  Joe       24        NaN
12  Donald    29        Waiter
.
.
.
.

我想 select 列 Job 中具有 NaN 值的行前后的行与行本身。为此，我有以下代码：

Rows = df[df. Shift(1, fill_value="dummy").Job. isna() | df.Job. isna()| df. Shift(-1, fill_value="dummy"). df. isna()]
print(Rows)

结果是这样的：

1   Sara      21        Doctor
2   john      23        NaN
3   kevin     22        Teacher
8   jason     20        Manager
9   Ali       23        NaN
10  Ahmad     21        Professor
11  Joe       24        NaN
12  Donald    29        Waiter

这里唯一的问题是第 10 行，它在结果中应该是双倍的，因为这一行是 NaN 之后的行，即第 9 行，同时是 NaN 值之前的行，即行号11（该行位于具有 NaN 值的两行之间）。所以最后我想要这个：

1   Sara      21        Doctor
2   john      23        NaN
3   kevin     22        Teacher
8   jason     20        Manager
9   Ali       23        NaN
10  Ahmad     21        Professor
10  Ahmad     21        Professor
11  Joe       24        NaN
12  Donald    29        Waiter

因此，具有 NaN 值的两行之间的每一行在结果中也应该是两次（或者应该是重复的）。有什么办法吗？任何帮助将不胜感激。

Answer 1

将 concat 用于之前、之后的行并按条件匹配：

m = df.Job.isna()

df = pd.concat([df[m.shift(fill_value=False)],
                df[m.shift(-1, fill_value=False)],
                df[m]]).sort_index()
print (df)
      Name  Age        Job
1     Sara   21     Doctor
2     john   23        NaN
3    kevin   22    Teacher
8    jason   20    Manager
9      Ali   23        NaN
10   Ahmad   21  Professor
10   Ahmad   21  Professor
11     Joe   24        NaN
12  Donald   29     Waiter

如何在 pandas 中的 NaN 前后 select 行？

How to select row before and after NaN in pandas?

python

nan

duplicates

shift

pandas