pandas - 如何在 Pandas 中将字符串分成多行

Question

我们有以下数据

  Name  genres

  A     Action|Adventure|Science Fiction|Thriller 
  B     Action|Adventure|Science Fiction|Thriller 
  C     Adventure|Science Fiction|Thriller

我想要这样的数据，我的数据框是

  Name  genres
  A     Action
  A     Adventure
  A     Science Fiction
  A     Thriller
  B     Action
  B     Adventure
  B     Science Fiction
  B     Thriller
  C     Adventure
  C     Science Fiction
  C     Thriller

这是我的代码

gen = df1[df1['genres'].str.contains('|')]
gen1 = gen.copy()
gen2 = gen.copy()
gen3 = gen.copy()
gen4 = gen.copy()
gen1['genres'] = gen1['genres'].apply(lambda x: x.split("|")[0])
gen2['genres'] = gen2['genres'].apply(lambda x: x.split("|")[1])
gen3['genres'] = gen3['genres'].apply(lambda x: x.split("|")[2])   
gen4['genres'] = gen4['genres'].apply(lambda x: x.split("|")[3])

我收到错误

IndexError: list index out of range

Answer 1

克里特岛类型列表 split , repeat 值来自 str.len 最后由 chain.from_iterable 压平列表:

from itertools import chain

genres = df['genres'].str.split('|')
df = pd.DataFrame({
    'Name' : df['Name'].values.repeat(genres.str.len()),
    'genres' : list(chain.from_iterable(genres.tolist()))
})

print (df)
   Name           genres
0     A           Action
1     A        Adventure
2     A  Science Fiction
3     A         Thriller
4     B           Action
5     B        Adventure
6     B  Science Fiction
7     B         Thriller
8     C        Adventure
9     C  Science Fiction
10    C         Thriller

编辑:

动态列数的解决方案:

print (df)
  Name                                     genres  col
0    A  Action|Adventure|Science Fiction|Thriller    2
1    B  Action|Adventure|Science Fiction|Thriller    3
2    C         Adventure|Science Fiction|Thriller    5

from itertools import chain

cols = df.columns.difference(['genres'])
genres = df['genres'].str.split('|')

df =  (df.loc[df.index.repeat(genres.str.len()), cols]
         .assign(genres=list(chain.from_iterable(genres.tolist()))))
print (df)
  Name  col           genres
0    A    2           Action
0    A    2        Adventure
0    A    2  Science Fiction
0    A    2         Thriller
1    B    3           Action
1    B    3        Adventure
1    B    3  Science Fiction
1    B    3         Thriller
2    C    5        Adventure
2    C    5  Science Fiction
2    C    5         Thriller