pandas DataFrame仅打印一次索引值

Question

import pandas as pd
li = [{"employee_id":1,"project_handled": "pas"},{"employee_id":1,"project_handled": "asap"},{"employee_id":2,"project_handled": "trimm"},{"employee_id":2,"project_handled": "fat"}]
df = pd.DataFrame(li)
df.set_index("employee_id",inplace=True)
print(df)

提供：

            project_handled
employee_id                
1                       pas
1                      asap
2                     trimm
2                       fat

我想要的是，在打印时索引值不应该重复：

            project_handled
employee_id                
1                       pas
                       asap
2                     trimm
                        fat

我想序列化这一点，并分享为excel使用DataFrame.to_excel应用程序接口。并且要求索引不应该在employee_id列中重复自身。

Answer 1

您需要设置MultiIndex

import pandas as pd
li = [{"employee_id":1,"project_handled": "pas"},{"employee_id":1,"project_handled": "asap"},{"employee_id":2,"project_handled": "trimm"},{"employee_id":2,"project_handled": "fat"}]
df = pd.DataFrame(li)
df['Something'] = 1
df.set_index(["employee_id", "project_handled"],inplace=True)
print(df)

我添加了Something，因为否则你会得到：

Empty DataFrame
Columns: []
Index: [(1, pas), (1, asap), (2, trimm), (2, fat)]

编辑

要在不使用project_handled的情况下创建它，需要使用空列和MultiIndex

df["another"] = ""
df.set_index(["employee_id", "another"],inplace=True)

Answer 2

如果您的唯一目标是以所需的方式将您的DataFrame打印到csv，并且您不需要为每个employee_id值只有一个单元格，那么您可以这样做：

import pandas as pd

li = [{"employee_id":1,"project_handled": "pas"},{"employee_id":1,"project_handled": "asap"},{"employee_id":2,"project_handled": "trimm"},{"employee_id":2,"project_handled": "fat"}]
df = pd.DataFrame(li)

def custom_func(x): 
    for i in range(1, x['employee_id'].size):
            x['employee_id'].iloc[i] = ''
    return x;

df['employee_id'] = df['employee_id'].apply(str)
df = df.groupby('employee_id').apply(custom_func).set_index('employee_id')
print(df)

输出：

            project_handled
employee_id
1                       pas
                       asap
2                     trimm
                        fat

df.to_csv('test.csv')的结果如下所示：

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