根据应用于列表的if条件筛选数据帧

Question

我有下面的df，我想创建一个if语句来只打印特定的行

pandas_dataframe = pd.DataFrame({'actors' : [['Tom Hanks', 'Tim Allen', 'Don Rickles', 'Jim Varney'],
                                             ['Robin Williams', 'Jonathan Hyde', 'Kirsten Dunst'],
                                             ['Walter Matthau', 'Jack Lemmon', 'Sophia Loren', 'n', 'ix']],
                                 'movie':['Toy Story', 'Jumanji', 'X-men']})

我只想打印演员列表中有一个长度为1的演员的行，因此我只想打印第三行，因为它至少有一个长度为1的演员

+--------------------------------------------------------------+------+
| actors                                                       |movie |
+--------------------------------------------------------------+------
|['Walter Matthau', 'Jack Lemmon', 'Sophia Loren', 'n', 'ix']  | X-men|
+--------------------------------------------------------------+------+

Answer 1

尝试：

import numpy as np

mask=pandas_dataframe.actors.explode().str.len().eq(1)
res=pandas_dataframe.loc[np.unique(mask.loc[mask].index)]

产出：

                                              actors  movie
2  [Walter Matthau, Jack Lemmon, Sophia Loren, n,...  X-men

Answer 2

使用lambda函数并应用：

import pandas as pd

df = pd.DataFrame(
    {
        "actors": [
            ["Tom Hanks", "Tim Allen", "Don Rickles", "Jim Varney"],
            ["Robin Williams", "Jonathan Hyde", "Kirsten Dunst"],
            ["Walter Matthau", "Jack Lemmon", "Sophia Loren", "n", "ix"],
        ],
        "movie": ["Toy Story", "Jumanji", "X-men"],
    }
)

filt = df.actors.apply(lambda x: any(len(y) == 1 for y in x))
df = df[filt]
print(df)

返回：

                                              actors   movie
2  [Walter Matthau, Jack Lemmon, Sophia Loren, n, ix]  X-men

Answer 3

您可以使用下面的代码，其中在一行中过滤数据帧

df[df.actors.apply(lambda o: any([len(x)==1 for x in o]))]