英文:
Group rows and add columns (delete repeated lines)
问题
如何分组行并添加新列。
看例子：
import pandas as pddf = pd.DataFrame({'name': ['Andy', 'Bob', 'Chad', 'Andy', 'Chad', 'Bob', 'George', 'Hank'],'col_1': ['A1', 'A2', 'A3', 'A4', 'B1', 'B2', 'B3', 'B4'],'col_2': [1, 1, 2, 2, 1, 1, 2, 2]})df.groupby(by="name")df
这生成以下结果：
name col_1 col_2
0 Andy A1 1
1 Bob A2 1
2 Chad A3 2
3 Andy A4 2
4 Chad B1 1
5 Bob B2 1
6 George B3 2
7 Hank B4 2
但我需要它看起来像这样：
name col_1 col_2 col_1 col_2
0 Andy A1 1 A4 2
1 Bob A2 1 B2 1
2 Chad A3 2 B1 1
3 George B3 2
4 Hank B4 2
谢谢
英文:
How to group rows and add new columns.
See the example:
import pandas as pddf = pd.DataFrame({'name': ['Andy', 'Bob', 'Chad', 'Andy', 'Chad', 'Bob', 'George', 'Hank'],'col_1': ['A1', 'A2', 'A3', 'A4', 'B1', 'B2', 'B3', 'B4'],'col_2': [1, 1, 2, 2, 1, 1, 2, 2]})df.groupby(by="name")df
This generates the following result:
name col_1 col_20 Andy A1 11 Bob A2 12 Chad A3 23 Andy A4 24 Chad B1 15 Bob B2 16 George B3 27 Hank B4 2
But I need it to look like this:
name col_1 col_2 col_1 col_20 Andy A1 1 A4 21 Bob A2 1 B2 12 Chad A3 2 B1 13 George B3 24 Hank B4 2
Thanks
答案1
得分: 1
尝试：
df['col'] = df.groupby('name').cumcount()out = df.pivot(index='name', columns='col').swaplevel(axis=1).sort_index(axis=1).fillna('')out.columns = (f'{b}_{a}' for a, b in out.columns)print(out)
输出：
col_0_1 col_0_2 col_1_1 col_1_2nameAndy A1 1.0 A4 2.0Bob A2 1.0 B2 1.0Chad A3 2.0 B1 1.0George B3 2.0Hank B4 2.0
英文:
Try:
df['col'] = df.groupby('name').cumcount()out = df.pivot(index='name', columns='col').swaplevel(axis=1).sort_index(axis=1).fillna('')out.columns = (f'{b}_{a}' for a, b in out.columns)print(out)
Prints:
col_1_0 col_2_0 col_1_1 col_2_1nameAndy A1 1.0 A4 2.0Bob A2 1.0 B2 1.0Chad A3 2.0 B1 1.0George B3 2.0Hank B4 2.0
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