联盟的指数清单

Question

如何在pandas中获得索引列表的并集？我有以下内容，但有更优雅的方式吗？

import pandas as pd

def union_list_indices( list_of_indices):
    new_index = pd.Index([])
    for index in list_of_indices:
        new_index = new_index.union(index)
    return(new_index)

Answer 1

参考this post，您可以进行一些小修改并尝试

from operator import or_ as union
from functools import reduce
import pandas as pd

df_a = pd.DataFrame.from_items([('A', [1, 2, 3]), ('B', [4, 5, 6])],
                        orient='index', columns=['one', 'two', 'three'])
df_b = pd.DataFrame.from_items([('C', [7, 8, 9]), ('D', [10, 11, 12])],
                        orient='index', columns=['one', 'two', 'three'])
df_c = pd.DataFrame.from_items([('E', [7, 8, 9]), ('F', [10, 11, 12])],
                        orient='index', columns=['one', 'two', 'three'])

def idx_union(mylist):
    idx = reduce(union, (index for index in mylist))
    return idx

bar = idx_union([df_a.index, df_b.index, df_c.index])   

不确定你是否认为它更优雅，但它确实存在。