筛选DataFrame中列内嵌套列表数量超4的行并拆分数据集

现有如下Pandas DataFrame（df）：

name        list
0    kfjh       [[a,b,c],[d,f,h],[g,k,l]]
1    jhkg       [[a,b,c],[d,f,h],[g,k,l],[f,k,j]]
2    khfg       [[a,b,c],[g,k,l]]
3    khkjgr     [[a,b,c],[d,f,h]]
4    kjrgjg     [[d,f,h]]
5    jkdgr      [[a,b,c],[d,f,h],[g,k,l], [g,j,l],[f,l,p]]
6    hgyr       [[a,b,c],[d,kf,h],[g,k,l], [g,j,l],[f,l,p]]
7    jkgtjd     [[f,l,p]]
8    nkjgrd     [t,t,i]

需求：筛选出list列中外层嵌套列表数量超过4的行组成df1，剩余行组成df2。

通过Pandas的apply方法计算每个list元素的长度，再用布尔索引完成筛选：

import pandas as pd

# 构造符合需求的示例DataFrame（修正原数据中括号不匹配问题）
data = {
    'name': ['kfjh', 'jhkg', 'khfg', 'khkjgr', 'kjrgjg', 'jkdgr', 'hgyr', 'jkgtjd', 'nkjgrd'],
    'list': [
        [['a','b','c'],['d','f','h'],['g','k','l']],
        [['a','b','c'],['d','f','h'],['g','k','l'],['f','k','j']],
        [['a','b','c'],['g','k','l']],
        [['a','b','c'],['d','f','h']],
        [['d','f','h']],
        [['a','b','c'],['d','f','h'],['g','k','l'], ['g','j','l'],['f','l','p']],
        [['a','b','c'],['d','kf','h'],['g','k','l'], ['g','j','l'],['f','l','p']],
        [['f','l','p']],
        ['t','t','i']
    ]
}
df = pd.DataFrame(data)

# 生成筛选条件：list列元素长度大于4
mask = df['list'].apply(len) > 4

# 拆分得到目标DataFrame
df1 = df[mask]
df2 = df[~mask]

df1输出： #

name                                              list
5  jkdgr  [[a, b, c], [d, f, h], [g, k, l], [g, j, l], ...
6   hgyr  [[a, b, c], [d, kf, h], [g, k, l], [g, j, l], ...

df2输出： #

name                                  list
0     kfjh        [[a, b, c], [d, f, h], [g, k, l]]
1     jhkg  [[a, b, c], [d, f, h], [g, k, l], [f,...
2     khfg              [[a, b, c], [g, k, l]]
3   khkjgr              [[a, b, c], [d, f, h]]
4   kjrgjg                        [[d, f, h]]
7  jkgtjd                        [[f, l, p]]
8  nkjgrd                          [t, t, i]

内容的提问来源于stack exchange，提问作者user20777609